tag:blogger.com,1999:blog-71721438576932726482024-03-18T03:14:55.808-07:00Audio Musings by Sean OliveA blog about the science of sound recording and reproductionDr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.comBlogger53125tag:blogger.com,1999:blog-7172143857693272648.post-51707769766153063452023-07-28T15:55:00.004-07:002023-07-31T10:53:15.407-07:00The Influence of Program Material on Sound Quality Ratings of In-Ear Headphones <p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmBbXWMPI8NAHOxEsUL0FvsUO-SIv13G1fJTawMk5vZGLTUpL8TfnkHHjvkW1Mv-iQQjr2waZLjR3A7fyfzRFEIizZLZLRQ1C4xiohJYB6YPcat_UZQFgip0974zl5DXWmT0FPFTWiJWUPBzSbzOr1UiPspq-_qhxr1N-Jlg644EMvQdyHTPyGk98ogw/s960/Program%20Spectra.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="540" data-original-width="960" height="311" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmBbXWMPI8NAHOxEsUL0FvsUO-SIv13G1fJTawMk5vZGLTUpL8TfnkHHjvkW1Mv-iQQjr2waZLjR3A7fyfzRFEIizZLZLRQ1C4xiohJYB6YPcat_UZQFgip0974zl5DXWmT0FPFTWiJWUPBzSbzOr1UiPspq-_qhxr1N-Jlg644EMvQdyHTPyGk98ogw/w551-h311/Program%20Spectra.png" width="551" /></a></div><p> <br /><span style="font-family: inherit; font-size: large; text-align: start;">Choosing program material for subjective evaluation of audio components is challenging because the acoustic characteristics and qualities of the recordings themselves can bias and influence the results [1], [2]. The programs must be sensitive to and reveal artefacts present in the devices under test, otherwise an invalid null result may occur (type II error). Ideally, the programs should be well recorded and not contain artefacts that may be inadvertently attributed to the headphone or loudspeaker. For example, an accurate headphone may be misperceived as sounding too bright or too full if the recorded program contains an excessive amount of boosted high or low frequency information. These so-called “circle of confusion” errors [3] caused by a lack of meaningful loudspeaker-headphone standards make it difficult to choose neutral programs that don’t bias listening tests.</span></p><p></p><blockquote style="border: none; margin: 0px 0px 0px 40px; padding: 0px;"><div class="separator" style="clear: both; text-align: center;"><div class="page" style="text-align: start;" title="Page 1"><div class="layoutArea"><div class="column"><p><span style="font-family: inherit; font-size: medium;"></span></p></div></div></div></div></blockquote><div class="separator" style="clear: both; text-align: center;"><div class="page" style="text-align: start;" title="Page 1"><div class="layoutArea"><div class="column"><p><span style="font-family: inherit; font-size: medium;">It would be ideal if there existed a list of recommended programs that meet all the above criteria, or an objective method for selecting the best programs. Unfortunately, the current listening test standards provide neither solution:</span></p><p><span style="font-family: inherit; font-size: medium;"><span style="font-style: italic;">“...There is no universally suitable programme material that can be used to assess all systems under all conditions. Accordingly, critical programme material must be sought explicitly for each system to be tested in each experiment. The search for suitable material is usually time-consuming; however, unless truly critical material is found for each system, experiments will fail to reveal differences among systems and will be inconclusive. A small group of expert listeners should select test items out of a larger selection of possible candidates.” </span>[2].</span></p></div></div></div></div><div><span style="font-size: medium;"><br /></span></div><p></p><div><div class="page" title="Page 2"><div class="layoutArea"><div class="column"><p><span style="font-family: inherit; font-size: medium;">Some insight into selecting effective programs for headphone evaluation may be gained from previous loudspeaker research where the spectral attributes are best evaluated using programs containing wideband, continuous spectrally dense signals. Low and medium Q resonances in loudspeakers are most easily detected using wide band continuous signals, whereas higher Q resonances are most sensitive to impulsive, discontinuous signals [4], [5]. The performance of listeners in categorizing spectral distortions added to headphones increases as the power spectral density of the program increases [6]. While we don’t recommend evaluating headphones using pink noise, there may be benefits in using music tracks that have broadband continuous signals mixed with some impulsive transient sounds as well. For judging the spatial and distortion attributes of headphones a different type of program may be required.</span></p><p><span style="font-family: inherit; font-size: medium;">A listener’s familiarity with the program and their affection for it from a musical or emotional perspective may also influence their sound quality judgements. Naïve listeners and audiophiles often criticize formal listening tests because they’re unfamiliar with the programs, or they dislike them. Whether this affects their performance as listeners is not well understood. ITU-R BS 1116 recommends: “the artistic or intellectual content of a programme sequence should be neither so attractive nor so disagreeable or wearisome that the subject is distracted from focusing on the detection of impairments.” [1].</span></p><p><span style="font-family: inherit; font-size: medium;">A </span><span style="font-family: inherit; font-size: medium;"> listening experiment was designed to address some of the above questions: 1) which programs are most effective at producing sensitive and reliable sound quality ratings of headphones 2) to what extent does familiarity with the program play a role and 3) are there physical properties of the program that can help predict their effectiveness in evaluating programs? A post-test survey was also administered to determine whether the listeners’ music preferences for certain programs and other factors influenced their performance and headphone ratings. </span></p><p><span style="font-size: medium;"><span style="font-family: inherit;">We published an AES preprint in 2017 that describes and summarizes the results of </span>the<span style="font-family: inherit;"> experiments which </span>can<span style="font-family: inherit;"> be found here </span> (<a href="https://www.aes.org/e-lib/browse.cfm?elib=18654" style="font-family: "Gill Sans MT";">https://www.aes.org/e-lib/browse.cfm?elib=18654</a>) <span style="font-family: inherit;"> .</span></span></p><p><span style="font-size: medium;">I've also created a PPT presentation that summarizes the experiments and results below.</span></p><p></p><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="377" src="https://www.youtube.com/embed/UtNvYeXR6RA" width="454" youtube-src-id="UtNvYeXR6RA"></iframe></div><br /><span style="font-size: medium;"><br /></span><p></p><p><span style="font-size: medium;"><b>References</b></span></p><div class="page" title="Page 11"><div class="layoutArea"><div class="column"><p><span style="font-family: inherit; font-size: medium;">[1] International Telecommunications Union, ITU-R BS 1116-3, “Methods for the subjective assessment of small impairments in audio systems,” <span style="color: blue;">http://www.itu.int/rec/R- REC-BS.1116-3-201502-I/en</span>, February 2015.</span></p></div><div class="column"><p><span style="font-family: Times;"><span style="font-size: medium;">[2] International Telecommunications Union, ITU-R BS 1534-3, “Methods for the subjective assessment of intermediate impairments in audio systems,” (October 2015).</span></span></p><p><span style="font-size: medium;"><span style="font-family: Times;">[3] Toole, Floyd, </span><span style="font-family: Times; font-style: italic;">The Acoustics and Psychoacoustics of Loudspeakers and Rooms, </span><span style="font-family: Times;">Focal Press, first edition 2008.</span></span></p><p><span style="font-family: Times;"><span style="font-size: medium;">[4] Toole, Floyd E., and Olive, Sean E. “The Modification of Resonances: Perception and Measurement,” AES Volume 36 Issue 3 pp. 122-142, (March 1988).</span></span></p><p><span style="font-family: Times;"><span style="font-size: medium;">[5] Olive, Sean E., Schuck, Peter L., Ryan, James G., Sally, Sharon L., Bonneville, Marc. “The Detection Thresholds of Resonances at Low Frequencies,” J. AES Volume 45 Issue 3 pp. 116-128, (March 1997).</span></span></p><p><span style="font-size: medium;"><span style="font-family: Times;">[6] Olive, Sean. E, “A Method for Training Listeners and Selecting Program Material for Listening Tests,” presented at the 97</span><span style="font-family: Times; vertical-align: 4pt;">th </span><span style="font-family: Times;">Audio Eng. Soc. Convention, preprint 9893, November 1994.</span></span></p></div></div></div></div></div></div></div>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com0tag:blogger.com,1999:blog-7172143857693272648.post-81891494739193038982022-03-04T00:24:00.002-08:002022-03-04T00:24:24.262-08:00The Perception and Measurement of Headphone Sound Quality - What Do Listeners Prefer?<p> </p><blockquote style="border: none; margin: 0 0 0 40px; padding: 0px;"><blockquote style="border: none; margin: 0 0 0 40px; padding: 0px;"><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjiURSiTGFZToWwpCb2VsgbiFiuhsjWmulSlAxlIxtFbwkoNfcoglh1So-7D918qhLhSsgqf-KME602nG6BNJn0babdVGWYsBaHA6KbnMMczeuJWKVc_37NPJakEnO0QMH5MYjNeHbP_5DHaVtv47EVyEzvhm222HqI0dn0dmLoKg9iFUCwEAzSfuQ" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img alt="" data-original-height="1220" data-original-width="912" height="272" src="https://blogger.googleusercontent.com/img/a/AVvXsEjiURSiTGFZToWwpCb2VsgbiFiuhsjWmulSlAxlIxtFbwkoNfcoglh1So-7D918qhLhSsgqf-KME602nG6BNJn0babdVGWYsBaHA6KbnMMczeuJWKVc_37NPJakEnO0QMH5MYjNeHbP_5DHaVtv47EVyEzvhm222HqI0dn0dmLoKg9iFUCwEAzSfuQ=w203-h272" width="203" /></a></div><p></p></blockquote></blockquote><p><br />In the spring 2022 edition of <a href="https://acousticstoday.org/" target="_blank"><b>Acoustics Today</b> </a>published today was published today you can find an article I wrote called, "<a href="https://acousticstoday.org/he-perception-and-measurement-of-headphone-sound-quality-what-do-listeners-prefer-sean-e-olive/">The Perception and Measurement of Headphone Sound Quality - What Do Listeners Prefer?"</a> </p><p>For headphone enthusiasts who find the HARMAN headphone research difficult to access (i.e. it's behind an Audio Engineering Society paywall), or comprehend (the research is reported in a series of 19+ technical papers), this article will hopefully provide some relief from your pain. The article is free and can be downloaded as a PDF. It summarizes the most relevant findings of our research in just 6,000 words (the maximum allowed by AT).</p><p><br />The current international headphone standards recommend a diffuse-field (DF) calibration for optimal sound quality. The article argues the standard is outdated, and has been largely rejected by the industry in favor of alternative targets deemed to be more neutral and preferred. The rejection of the DF target can be found in headphone surveys where the average measured frequency response deviates significantly from the DF target curve. Instead, the average response tends to approximate the in-room steady-state frequency response of a flat loudspeaker in a semi-reflective field (SRF) produced in a typical listening room. We've known what makes loudspeakers sound good for almost 40 years since the seminal loudspeaker papers were published by Dr. Floyd Toole in 1985-86. It turns out what makes a loudspeaker sound good, also applies to headphones. Who would have guessed?<br /><br />The in-room target response of an accurate loudspeaker became the starting point of the HARMAN target curve for headphones. Over several years, we conducted many controlled scientific listening tests to test the target curve against many headphones, refine it, and ensure it had a wide acceptance among different groups of listeners based on age, gender, listening experience and geographical location.</p><p> The results found there exist three segments of listeners based the headphone they preferred. The largest segment (64%) preferred the HARMAN target curve with two smaller segments that preferred something close to the HARMAN target curve with less bass (21%) and more bass (15%). We also found that membership in these segments tended to be related to factors such as age, listening experience and gender. Much like loudspeakers, we found that the preferred sound quality rating of a headphone can be modeled and predicted based how far its measured frequency deviates from the HARMAN target curve. <br /><br />Hopefully, this article will explain the motivation, major findings and conclusions of the research behind the HARMAN headphone target curve. Enjoy!</p><p><br /></p>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com0Oak Park, CA 91377, USA34.1791715 -118.76286855.868937663821157 -153.9191185 62.489405336178848 -83.6066185tag:blogger.com,1999:blog-7172143857693272648.post-41096842256707845092018-05-28T12:32:00.000-07:002018-05-28T12:40:23.611-07:00Hooked on the Science of Sound<div class="separator" style="clear: both; text-align: center;">
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This past month, I was interviewed by <a href="https://bksv.com/">Bruel & Kjaer'</a>s, "Waves Magazine" in their Expert Profile feature. For those people not familiar with <a href="https://en.wikipedia.org/wiki/Br%C3%BCel_&_Kj%C3%A6r">Bruel & Kjaer</a> located in Denmark they are one of the oldest (in operation since 1942) best known manufacturers of acoustic and vibration measurement equipment.</div>
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The interviewer was interested in how my career transitioned from musician to recording engineering to acoustic/psychoacoustics. Essentially, my career has been a world-wind trip through the <a href="http://seanolive.blogspot.com/2009/10/audios-circle-of-confusion.html">Circle of Confusion</a> where I was guided by my interests, curiosity in the perception and measurement of sound, and the opportunities I was presented at the time. There was no master plan. Hopefully, we've helped remove some of the confusion in the circle by providing with a better understanding of what influences the quality of recorded and reproduced sound, and how to make it better and more consistent.</div>
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You can read the entire interview <a href="https://bksv.com/en/about/waves/WavesArticles/2018/Hooked-on-the-science-of-sound">here:</a></div>
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Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com0tag:blogger.com,1999:blog-7172143857693272648.post-26527913447848961942017-02-17T13:02:00.000-08:002017-02-17T15:48:25.212-08:00TWiRT 337 – Predicting Headphone Sound Quality with Sean Olive<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
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<tr><td class="tr-caption" style="text-align: center;">The predicted sound quality of 61 different models of in-ear headphones (blue curve) versus their retail price (green bars).</td></tr>
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On February 16, 2017 I was interviewed by host <a href="https://about.me/kirkharnack">Kirk Harnack</a> on <a href="http://thisweekinradiotech.com/">This Week in Radio Tech</a>. The topic was <a href="https://www.youtube.com/watch?v=FD_5tj9yPdk"> "Predicting Sound Headphone Sound Quality"</a>. You can find the interview<a href="http://gfqnetwork.com/shows/this-week-in-radio-tech-2/predicting-headphone-sound-quality-sean-olive/"> here</a>.<br />
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During the interview, Kirk asked if it's possible to design a good sounding headphones for a reasonable cost. Or does one need to spend a considerable amount of cash to obtain good sound? Fortunately for consumers, my answer was that you can get decent sound without having to spend thousands or even hundreds of dollars. In fact, there is almost no correlation between price and sound quality based on our research.</div>
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I referred to the slide above that shows the predicted sound quality for 61 different models of in-ear headphones based on their measured frequency response. The correlation between price and sound quality is close to zero and, slightly negative: r = -.16 (i.e. spending more money gets you slightly worse sound on average).<br />
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So, if you think spending a lot of money on in-ear headphones guarantees you will get excellent sound, you may be sadly disappointed. One of the most expensive IE models ($3000) in the above graph, had a underwhelming predicted score of 20-25% depending what EQ setting you chose. The highest scoring headphone was a $100 model that we equalized to hit the Harman target response, which our research has shown to be preferred by the majority of listeners.</div>
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The sound quality scores in the graph are predicted using a model based on a small sample of headphones that were evaluated by trained listeners in double-blind test. The accuracy of the model is better than 96% but limited to the small sample we tested. We just completed a large listening test study involving over 30 models and 75 listeners that will allow us to build more accurate and robust predictive models. </div>
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The ultimate goal of this research is to accurately predict the sound quality of headphones based on acoustic measurements without having to conduct expensive and time consuming listening tests. The current engineering approach to tuning headphones is clearly not optimal based on the above slide. Will headphone industry standards, headphone manufacturers and audio review magazines use similar predictive models to reveal to consumers how good the headphones sound? What do you think?</div>
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Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com9tag:blogger.com,1999:blog-7172143857693272648.post-81548744706091766772016-08-16T13:26:00.003-07:002016-08-16T13:26:20.865-07:0015 Minutes with Harman’s Audio Guru Sean Olive: Sound & Vision Magazine Interview<div class="separator" style="clear: both; text-align: center;">
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<tr><td class="tr-caption" style="text-align: center;"><i><span style="background-color: white; font-family: arial, helvetica, sans-serif; font-size: 16px; text-align: left;">"The problem is that the current standard audio specifications for headphones and loudspeakers are almost useless in terms of indicating how good or bad they sound." —</span><span style="background-color: white; font-family: arial, helvetica, sans-serif; font-size: 16px; text-align: left;">Sean Olive</span><span style="background-color: white; font-family: arial, helvetica, sans-serif; font-size: 16px; text-align: left;"><br />Read more at <a href="http://www.soundandvision.com/content/15-minutes-harmans-audio-guru-sean-olive#Wyt4T8pATiWPVQ3Q.99">S&V Magazine</a> </span></i></td></tr>
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In May 2016, I was interviewed by editor <a href="http://www.soundandvision.com/writer/33083">Bob Ankosko </a>in <a href="http://www.soundandvisionmag.com/">Sound&Vision Magazine</a> about my views of where audio currently is,and where it is going. You can read the interview <a href="http://www.soundandvision.com/content/15-minutes-harmans-audio-guru-sean-olive#Wyt4T8pATiWPVQ3Q.99">here</a>. One of the recurring questions that I get asked is whether people really care about sound quality anymore. The fact that a recent study found 55% of Americans typically listen to music through their laptop speakers doesn't bode well for the immediate future. While the recent focus has been on the poor quality of the source material (e.g. compressed MP3), a typical laptop speaker system won't produce the bottom 3-4 octaves of music whether or not the music is compressed or recorded in high resolution (e.g. 24-bit, 96 kHz).<div>
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In terms of home loudspeakers, the trend is smaller size, fewer number of loudspeakers, and wireless. Sound Bars and small, powered wireless speakers are what consumers currently want in their homes. The current challenge for engineering is to build high quality systems with these features but still deliver good sound for prices that consumes will pay. The fact that more consumers are expecting a high quality (and branded) audio system in their automobiles suggests that the desire to have good audio is not dead.<div>
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What do you think the future holds for audio and sound quality?</div>
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Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com0tag:blogger.com,1999:blog-7172143857693272648.post-10092740292862497052016-04-22T14:10:00.002-07:002016-04-23T15:29:10.498-07:00A Virtual Headphone Listening Test Method<div class="separator" style="clear: both; text-align: center;">
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<i><span style="font-size: small;">Fig. 1 The Harman Headphone Virtualizer App allows listeners to make double-blind comparisons of different headphones through a high-quality replicator headphone. The app has two listening modes: a sighted mode (shown) and a blind mode (not shown) where listeners are not biased by non-auditory factors (brand, price, celebrity endorsement,etc). Clicking on the picture will show a larger version.</span></i></div>
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Early on in our headphone research we realized there was a need to develop a listening test method that allowed us to conduct more controlled double-blind listening tests on different headphones. This was necessary in order to remove tactile cues (headphone weight and clamping force), visual and psychological biases (e.g. headphone brand, price, celebrity endorsement,etc ) from listeners' sound quality judgements of headphones. While these factors (apart from clamping force) don't physically affect the sound of headphones, our <a href="http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html">previous research</a> [1] into blind vs. sighted listening tests revealed their cognitive influence affects listeners' loudspeaker preferences [1], often in adverse ways. In sighted tests, listeners were also less sensitive and discriminating compared to blind conditions when judging different loudspeakers including their interaction with different music selections and loudspeaker positions in the room. For that reason, consumers should be dubious of loudspeaker and headphone reviews that are based solely on sighted listening.</div>
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While blind loudspeakers listening tests are possible through the addition of an <a href="http://seanolive.blogspot.com/2010/07/harman-kardons-quest-to-standardise.html">acoustically-transparent- visually-opaque-curtain</a>, there is no simple way to hide the identity of a headphone when the listener is wearing it. In our <a href="http://seanolive.blogspot.com/2013/04/the-relationship-between-perception-and.html">first headphone listening tests</a>, the experimenter positionally substituted the different headphones onto the listener's head from behind so that the headphone could not be visually identified. However, after a couple of trials, listeners began to identify certain headphones simply by their weight and clamping force. One of the easiest headphones for listeners to identify was the <a href="https://www.audeze.com/products/lcd-collection/lcd2">Audeze LCD-2,</a> which was considerably heavier (522 grams) and more uncomfortable than the other headphones. The test was essentially no longer blind.</div>
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To that end, a virtual headphone method was developed whereby listeners could A/B different models of headphones that were virtualized through a single pair of headphones (the replicator headphone). Details on the method and its validation were presented at the <a href="http://www.aes.org/e-lib/browse.cfm?elib=16874">51st Audio Engineering Society International Conference on Loudspeakers and Headphones</a> [2] in Helsinki, Finland in 2013. A PDF of the slide presentation can be found <a href="https://dl.dropboxusercontent.com/u/16343460/Slide%20Presentation%20For%20A%20Virtual%20Headphone%20Listening%20Test%20Methodology%20AES%2051th%20Conference.pdf"> here</a>.</div>
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Headphone virtualization is done by measuring the frequency response of the different headphones at the DRP (eardrum reference point) using a <a href="http://www.gras.dk/index.php/industries/consumer-audio-electronics/headphone-earphone-testing/43ag-3.html">G.R.A.S. 45 AG</a>, and then equalizing the replicator headphone to match the measured responses of the real headphones. In this way, listeners can make instantaneous A/B comparisons between any number of virtualized headphones through the same headphone without the visual and tactile clues biasing their judgment. More details about the method are in the <a href="https://dl.dropboxusercontent.com/u/16343460/Slide%20Presentation%20For%20A%20Virtual%20Headphone%20Listening%20Test%20Methodology%20AES%2051th%20Conference.pdf">slides</a> and <a href="http://www.aes.org/e-lib/browse.cfm?elib=16874">AES preprint</a>.</div>
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An important questions is: "How accurate are the virtual headphones compared to the actual headphones"? In terms of their linear acoustic performance they are quite similar. Fig. 2 compares the measured frequency response of the actual versus virtualized headphones. The agreement is quite good up to 8-10 kHz above which we didn't aggressively equalize the headphones because of measurement errors and large variations related to headphone positioning both on the coupler and the listeners' head.</div>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHLe3P28nN87xvZEyDh63nO4sXRKYHnB2Dl5iB9URMCB4Gejz8tmVvFmM1hE5uqnjUZSEijUa1Z0Yd1KbFefpZNyLI3meCCzjnjwLZMkyAYY5us5XYNwj1eeq20A_4rIJDyIBVZmHXjws/s1600/Virtual+Headphone+Measurements.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHLe3P28nN87xvZEyDh63nO4sXRKYHnB2Dl5iB9URMCB4Gejz8tmVvFmM1hE5uqnjUZSEijUa1Z0Yd1KbFefpZNyLI3meCCzjnjwLZMkyAYY5us5XYNwj1eeq20A_4rIJDyIBVZmHXjws/s400/Virtual+Headphone+Measurements.jpg" width="400" /></a></td></tr>
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<i><span style="font-size: small;">Fig. 2 Frequency response measurements of the6 actual versus virtualized headphones made on a GRAS 45 AG coupler with pinna. The dotted curves are based on the physical headphone and the solid curves are from the virtual (replicator) headphone. The measurements of the right channel of the headphone (red curves) have been offset by 10 dB from the left channels (blue curve) for visual clarify. </span></i><i><span style="font-size: small;">Clicking on the picture will show a larger version.</span></i></div>
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More importantly, "Do the actual and virtual headphones sound similar"? To answer this question we performed a validation experiment where listeners evaluated 6 different headphone using both standard and virtual listening methods Listeners gave both preference and spectral balance ratings in both standard and virtual tests. For headphone preference ratings the correlation between standard and virtual test results was r = 0.85. A correlation of 1 would be perfect but 85% agreement is not bad, and hopefully more accurate than headphone ratings based on sighted evaluations. </div>
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The differences between virtual and standard test results we believe are in part due to nuisance variables that were not perfectly controlled across the two test methods. A significant nuisance variable would likely be headphone leakage that would affect the amount of bass heard depending on the fit of the headphone on the individual listener. This would have affected the results in the standard test but not the virtual one where we used an open-back headphone that largely eliminates leakage variations across listeners. Headphone weight and tactile cues were present in the standard test but not the virtual test, and this could in part explain the differences in results. If these two variables could be better controlled even higher accuracy can be achieved in virtual headphone listening.</div>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEih6BsHdGZzCJ_RhO2Xe7jtkyjO42zx3Pwle5Ar1VjgR50uyOlIcAnRz66lkSRIA0HsWI7__kEEewMCl__l4tm8l45tOMPxPopGMXun3FarZ5pz-uLQG87vE43EVUOPaq_M37QRd6V-h7I/s1600/Standard+vs+Virtual.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEih6BsHdGZzCJ_RhO2Xe7jtkyjO42zx3Pwle5Ar1VjgR50uyOlIcAnRz66lkSRIA0HsWI7__kEEewMCl__l4tm8l45tOMPxPopGMXun3FarZ5pz-uLQG87vE43EVUOPaq_M37QRd6V-h7I/s400/Standard+vs+Virtual.jpg" width="400" /></a></td></tr>
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<i><span style="font-size: small;">Fig.3 The mean listener preference ratings and 95% confidence intervals shown for the headphones rated using the Standard and Virtual Listening Test Methods. The Standard Method listeners evaluated the actual headphones with tactile/weigh biases and any leakage effects. In the Virtual Tests, there were no visual or tactile cues about the headphones. Note: </span></i><i><span style="font-size: small;">Clicking on the picture will show a larger version.</span></i></div>
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Some additional benefits from virtual headphone testing were discovered besides eliminating sighted and psychological biases: the listening tests are faster, more efficient and more sensitive. When listeners can quickly switch and compare all of the headphones in a single trial, auditory memory is less of a factor, and they are better able to discriminate among the choices. Since this paper was written in 2013, we've improved the accuracy of the virtualization in part by developing a custom pinnae for our GRAS 45 CA that better simulates the leakage effects of headphones measured on real human subjects [3].</div>
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Finally, it's important to acknowledge what the virtual headphone method doesn't capture: 1) non-minimum phase effects (mostly occurring at higher frequencies) and 2) non-linear distortions that are level-dependent. The effect of these two variables on virtual headphone test method have been recently tested experimentally and will be the topic of a future blog posting. Stay tuned. </div>
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<b>References</b></div>
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<span style="font-family: inherit;">[1] <span class="Apple-style-span" style="color: #222222;">Floyd Toole and Sean Olive,”Hearing is Believing vs. Believing is Hearing: Blind vs. Sighted Listening Tests, and Other Interesting Things,” presented at the 97th AES Convention, preprint 3894 (1994). Download </span><span style="color: #888888; line-height: normal; text-align: justify; text-decoration: underline;"><a href="http://www.aes.org/e-lib/browse.cfm?elib=6338" style="color: #888888; text-align: justify; text-decoration: none;">here.</a></span></span></div>
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<span style="font-family: inherit;">[2] Sean E.<span style="background-color: white;"> </span><span class="meta-data" style="margin: 0px; padding: 0px 3em 0px 0px;">Olive, Sean E., Todd Welti, and Elisabeth McMullin, "A Virtual Headphone Test Methodology," AES 51st International Conference on Loudspeakers and Headphones, Helsinki,Finland (August 21, 2013). Download <a href="http://www.aes.org/e-lib/browse.cfm?elib=16874">here</a></span></span></div>
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<span style="font-family: inherit;">[3] Todd Welti, "I<a href="http://www.aes.org/e-lib/browse.cfm?elib=17699" style="background-color: white; border-bottom-style: none; margin: 0px; padding: 0px; text-decoration: none;">mproved Measurement of Leakage Effects for Circum-Aural and Supra-Aural Headphones</a>," presented at the 38th AES Convention, (May 2014). Download <a href="http://www.aes.org/e-lib/browse.cfm?elib=17699">here.</a></span></div>
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<br />Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com8tag:blogger.com,1999:blog-7172143857693272648.post-60575121971410791872016-03-31T16:07:00.000-07:002016-04-07T01:45:01.713-07:00Harman Gives Loudspeaker Course To U of Rochester Engineering Students<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3q9W17RvU745yDSWGgdtbpCiDQzvfdQ9VYCkpx5Im7_hDt_7fmskuqUvSAFoeexfH_Gnni72UsiPoGgfrwVanKj1Fg4fi7VQNgVY4aHjgjBr_Oc2KoeIsP_eqxxSM-vK6ZLPYlmm9hUE/s1600/Mark+Glazer.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3q9W17RvU745yDSWGgdtbpCiDQzvfdQ9VYCkpx5Im7_hDt_7fmskuqUvSAFoeexfH_Gnni72UsiPoGgfrwVanKj1Fg4fi7VQNgVY4aHjgjBr_Oc2KoeIsP_eqxxSM-vK6ZLPYlmm9hUE/s400/Mark+Glazer.jpg" width="375" /></a></div>
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Recently Mark Glazer, Principal Engineer at <a href="http://www.harmanluxuryaudio.com/">Harman Luxury Audio</a> and <a href="http://www.revelspeakers.com/">Revel Loudspeakers</a> gave an invited lecture to <a href="http://www.ame.rochester.edu/">University of Rochester Audio/Acoustic Engineering Students.</a> The students are part of the graduate acoustic and music engineering program that is overseen by <a href="http://www.ece.rochester.edu/projects/Bocko/Bocko.html">Professor Mark Bocko</a>, Distinguished Professor, Electrical and Computer Engineering. By exposing the students to the fascinating engineering and science of loudspeakers, it is hoped the students will consider a future career in loudspeaker or audio engineering.</div>
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The 1-hour lecture gave an overview of what are the current best practices in designing a modern-day loudspeaker. </div>
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The proof of good loudspeaker design is ultimately judged on how good it sounds. Dr. Sean Olive (me), Acoustic Research Fellow at Harman International presented an overview of the science of evaluating loudspeakers, which included test results from a competitive benchmarking of the new <a href="http://www.revelspeakers.com/productdetail/~/product/m16.html">Revel Concerta 2 M16</a> (designed by Mark Glazer) against three competitors. The results of the listening test results were generally predictable based on the set of anechoic measurements made of the different loudspeakers.</div>
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Following the lecture, we got a tour of the University's engineering facilities, which include some impressive 3D laser scanning tools for studying the vibrational modes of loudspeakers. We heard some very novel flat-panel loudspeakers with vibrational mode control developed by the Ph.D students and Professor Bocko, followed by presentations of research projects undertaken by the Masters and Ph.D. engineering students who are working in acoustics and audio-related research. Overall, the quality of acoustic and music research being done there is impressive. As always, Professor Bocko was a gracious host, and we look forward to a return visit (hopefully in the summer or fall months).</div>
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Mark Glazer's speaker design course slides are available<a href="https://dl.dropboxusercontent.com/u/16343460/An%20Engineering%20Students%20Guide%20to%20Loudspeaker%20Design%2C%20March%2031.pdf"> here:</a></div>
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Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com0tag:blogger.com,1999:blog-7172143857693272648.post-15620818300435304962015-11-07T12:32:00.002-08:002015-11-09T09:36:26.770-08:00Factors that Influence Listeners’ Preferred Bass and Treble Levels in Headphones<div class="separator" style="clear: both; text-align: center;">
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<span style="font-family: inherit;">Most people would agree that headphone purchase decisions are heavily influenced by the brand and styling (size, weight, color, quality of materials). But what is considered stylish and fashionable by me is not shared by my 15-year old daughter (this week donning purple hair), and vice versa. In other words, the perceived visual aesthetic of the headphone is really in the the eyes and mind of the beholder, and this can vary with</span><span style="font-family: inherit;"> age, gender, culture, and other demographic category. </span><br />
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<span style="font-family: inherit;"><b><i>But what about sound quality?</i> </b>To what extent does the consumer's age, gender, culture and prior listening experience influence their taste in headphone sound quality? Is there a scientific basis for headphone manufacturers to design headphones that have different amounts of bass and treble aimed to satisfy the tastes of a targeted demographic group? </span><br />
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<span style="font-family: inherit;">To answer this question, we recently conducted a<span style="background-color: white;"> study on factors that influence listeners’ preferred bass and treble balance in headphone sound reproduction. Using a method of adjustment a total of 249 listeners adjusted the relative treble and bass levels of a headphone that was first equalized at the eardrum reference point (DRP) to match the in-room steady-state response of a reference loudspeaker in a reference listening room. Listeners repeated the adjustment five times using three stereo music programs. The listeners included males and females from different age groups, listening experiences, and nationalities (Canada, USA, Germany and China). The results provide evidence that the preferred bass and treble balances in headphones was influenced by several factors including program, and the listeners’ age, gender, and prior listening experience. The younger and less experienced listeners on average preferred more bass and treble in their headphones compared to the older, more experienced listeners. Female listeners on average preferred about 1 dB bass and 2 dB treble than their male counterparts. Listeners over 55 years preferred less bass and more treble than the younger listeners suggested that they were compensating for possible hearing loss that is associated with increased age.</span></span><br />
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<iframe allowfullscreen="" class="YOUTUBE-iframe-video" data-thumbnail-src="https://i.ytimg.com/vi/ySQV5OR71e4/0.jpg" frameborder="0" height="266" src="https://www.youtube.com/embed/ySQV5OR71e4?feature=player_embedded" width="320"></iframe></div>
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<span style="font-family: inherit;"><span style="background-color: white;">We recently presented the results of this study at the 139th Audio Engineering Society Convention in New York City, October 29th-November 1, 2015. The paper is available for download in</span></span> <a href="http://www.aes.org/e-lib/browse.cfm?elib=17940">AES e-library</a>. A PDF copy of the presentation can be found <a href="https://dl.dropboxusercontent.com/u/16343460/AES%20139%20Presentation%202015%20Olive%20and%20Welti%20Preferred%20Bass%20and%20Treble%20Levels.pdf">here</a>. Or you can view an animated version of the presentation on <a href="https://youtu.be/ySQV5OR71e4">Youtube.</a>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com9tag:blogger.com,1999:blog-7172143857693272648.post-1475020528915787132014-10-22T11:35:00.000-07:002017-08-28T12:18:59.405-07:00The Influence of Listeners' Experience, Age and Culture on Headphone Sound Quality Preferences<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiWbREL_aYzRbv14692ed2vTfL4w5cm5IiYzYjiIb2Lh8eDbJromWf0cMIDq45ams9BtoDkjdPGdMJ-h4Z-NmZD2HLYF1jTGgtdHszeIpoBrVNOcrmAJdoPr4z-ac2vZat5RY8Mq3ApGg/s1600/AES137PreferencePage1.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiWbREL_aYzRbv14692ed2vTfL4w5cm5IiYzYjiIb2Lh8eDbJromWf0cMIDq45ams9BtoDkjdPGdMJ-h4Z-NmZD2HLYF1jTGgtdHszeIpoBrVNOcrmAJdoPr4z-ac2vZat5RY8Mq3ApGg/s1600/AES137PreferencePage1.png" width="361" /></a></div>
At the recent <a href="http://www.aes.org/events/137/" target="_blank">137th convention</a> of the Audio Engineering Society we presented our latest research paper entitled, <b>"The Influence of Listeners' Experience, Age and Culture on Headphone Sound Quality Preferences.</b>"<br />
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The paper describes some double-blind <span style="font-family: "timesnewromanpsmt";"> headphone listening tests conducted in four different countries (Canada, USA, China and
Germany) involving 238 listeners of different ages, gender and listening experiences. Listeners gave comparative
preference ratings for three popular headphones and a new reference headphone that were virtually presented
through a common replicator headphone equalized to match their measured frequency responses. In this way, biases
related to headphone brand, price, visual appearance and comfort were removed from listeners’ judgment of sound
quality. On average, listeners preferred the reference headphone that was based on the in-room frequency response
of an accurate loudspeaker calibrated in a reference listening room. This was generally true regardless of the
listener’s experience, age, gender and culture. This new evidence suggests a headphone standard based on this new
target response would satisfy the tastes of most listeners. </span><br />
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<span style="font-family: "timesnewromanpsmt";">The paper is available for download from the <a href="http://www.aes.org/e-lib/browse.cfm?elib=17500" target="_blank">AES e-library</a>. You can also find a PDF of our presentation<span id="goog_150839783"></span> <a href="https://www.dropbox.com/s/cty4728c8so4ic2/AES%20137%20The%20Influecne%20of%20Listeners%27%20Experence%2C%20Age%2C%20and%20Cultire%20on%20Headphone%20Sound%20Quality%20Preferences%20.key.pdf?dl=0" target="_blank">here</a> or view the presentation on <a href="https://www.youtube.com/watch?v=sWkHIxmIqjo&feature=youtu.be" target="_blank">YouTube</a>.</span><br />
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<span style="font-family: "timesnewromanpsmt";"><br /></span>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com1tag:blogger.com,1999:blog-7172143857693272648.post-44878198359269430642014-06-11T09:07:00.000-07:002014-06-12T13:47:19.988-07:00My Article on Headphone Sound Quality in 2014 LIS<a href="http://read.uberflip.com/i/324330/22" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;" target="_blank"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwo-by6qzT1rskquCgrNFaV000e52KNH3px1INz0_PsZmgwrEsYm7yTYRT6eCIPW0EX0Cp9dDvvXa_Ns5iJQpIYpFiVESdbvjA91vishwXqEBeDGkBfst9Q6cO192na361IVseDshhUTs/s1600/Article+on+Headphones.png" height="320" width="400" /></a>The <a href="http://read.uberflip.com/i/324330/22" target="_blank">2014 Loudspeaker Industry Sourcebook</a> came out this week. In it, you can find an article I wrote called "<a href="http://read.uberflip.com/i/324330/22" target="_blank">Perceiving and Measuring Headphone Sound Quality: Do Listeners Agree on What Makes a Headphone Sound Good</a>?"<br />
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The article is a summary of some recent published research we've conducted at Harman on the perception and measurement of headphone sound quality.<br />
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Together, these studies provide scientific evidence that when headphone brand, price, fashion, and celebrity endorsement are removed subjective evaluations, listeners generally agree on what makes a headphone sound good.<br />
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So far, this has been true regardless of users' listening training, age, or culture. The more preferred headphones tend to have a smooth, extended frequency response that approximates an accurate loudspeaker's in-room response. This new target frequency response could provide the basis for a new and improved headphone target response. You can find more details on the research <a href="http://read.uberflip.com/i/324330/22" target="_blank">here</a>.<br />
<br />Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com7Northridge, Los Angeles, CA, USA34.2381251 -118.53012334.133110599999995 -118.6914845 34.3431396 -118.3687615tag:blogger.com,1999:blog-7172143857693272648.post-86600245986731815312014-01-28T16:34:00.002-08:002014-01-30T21:11:15.105-08:00Interview in Professional Sound: The Lack of Meaningful Loudspeaker & Headphone Specs<div class="separator" style="clear: both; text-align: center;">
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<span style="text-align: justify;">Last October, I was in Toronto giving a presentation to the local AES section on the</span><a href="http://www.aes.org/sections/reports/?ID=1405" style="text-align: justify;"> perception and measurement of headphones</a><span style="text-align: justify;">. After the talk, I sat down with Mike Raine from </span><a href="http://www.professional-sound.com/" style="text-align: justify;"> Professional Sound</a><span style="text-align: justify;"> for an interview. Some of what we discussed is summarized in this article called </span><a href="http://professional-sound.com/soundadvice/the-lack-of-meaningful-loudspeaker-headphone-specs/#more-974" style="text-align: justify;">Sound Advice.</a><br />
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The theme of article is a recurring one that I've discussed before in this blog (see "<a href="http://seanolive.blogspot.com/2013/07/the-science-and-marketing-of-sound.html">The Science and Marketing of Sound Quality"</a> and "<a href="http://seanolive.blogspot.com/2009/01/what-loudspeaker-specifications-are.html">What Loudspeaker Specifications are Relevant to Sound Quality?</a>"). The bottom line is that the loudspeaker and headphone industry has utterly failed to provide consumers meaningful product specifications that indicate how truly good (or bad) the products sound. Read on to find out why.</div>
Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com3tag:blogger.com,1999:blog-7172143857693272648.post-24247307572009976722014-01-06T01:44:00.001-08:002014-01-06T02:43:46.085-08:00Do Listeners Agree on What Makes a Headphone Sound Good?<span style="font-family: inherit;">This past weekend, I attended the <a href="http://almin.memberclicks.net/2014-winter-symposium-presentations">ALMA 2014 Winter Symposium</a> in Las Vegas where I gave a talk entitled, "<a href="http://almin.memberclicks.net/sean-olive---presenter-page">The Perception and Measurement of Headphone Sound Quality: Do Listeners Agree on What Makes a Headphone Sound Good?</a>" The presentation gives a summary of some key findings of our headphone research conducted over the past 18 months. It also includes some unpublished preliminary findings from a current study on headphone preferences of trained and untrained listeners both young and old from China, Canada, USA, and Germany. The focus of this study is to determine whether listeners from different cultures and age groups prefer the same headphone sound quality as trained listeners when the influence of headphone brand, fashion and celebrity endorsement are removed from the test. </span><br />
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<span style="font-family: inherit;">The abstract for my talk is reproduced below. A PDF of the slide presentation can be downloaded <a href="https://db.tt/XMgixjBP">here:</a></span><br />
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<i><span style="font-family: inherit;">The popularity of headphones has now exploded to produce annual worldwide sales of almost $10 billion. Premium headphones ($100+) now account for 90% of the annual revenue growth, as consumers’ audio experiences are becoming a primarily mobile one. Market research indicates sound quality is a driving factor in headphone purchases with brand and fashion also being important factors among younger consumers. Yet, ironically the science behind what makes a headphone sound good and how to measure it is poorly understood. This combined with the lack of perceptually meaningful headphone standards may explain why purchasing a headphone today is like playing Russian Roulette with your ears. The magic bullet to achieving more consistent headphone sound quality is </span><span style="font-family: inherit;">science.</span></i><br />
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<span style="font-family: inherit;"><i><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;"><br /></span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">We recently conducted a series of controlled double-blind listening tests on popular headphones (both real and virtualized models) to better understand the </span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">relationship between their perceived sound quality and acoustic performance <span style="font-family: inherit;">[1,3,5]</span> A second set of experiments measured listener preferences of different </span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">headphones equalized to different target curves responses including the recommended diffuse and free-field target curves [2]. A third set of experiments used a </span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">method of adjustment where listeners directly adjusted their preferred bass and treble levels of a headphone and loudspeaker equalized to the same in-room </span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">target response [4]. In this way, we could measure the variation in individual listeners’ taste in headphone spectral balance, and determine the extent to which </span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">the preferred headphone target response should simulate the response of an accurate loudspeaker in a reference listening room.</span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;"><br /></span></i></span><br />
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<span style="font-family: inherit;"><i><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">Together, the results of this research show that when the influence of brand, fashion and celebrity endorsement are removed from headphone tests, both </span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">trained and untrained listeners regardless of age and culture, generally agre</span><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;">e on which headphones sound best and this correlates to their acoustical performance.</span></i></span><br />
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<span style="font-family: inherit;"><span lang="en-US" style="background-color: transparent; border: 0px; color: black; margin: 0px; outline: 0px; padding: 0px;"><b>References</b></span></span><br />
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<li><span style="font-family: inherit;">Sean E. Olive and Todd Welti, "<a href="http://www.aes.org/e-lib/browse.cfm?elib=16486">The Relationship between Perception and Measurement of Headphone Sound Quality</a>", presented at the 133rd Audio Eng. Soc. Convention, San Francisco, USA, (October 2012).</span></li>
<li>Sean E. Olive, Todd Welti and Elisabeth McMullin, "<a href="http://www.aes.org/e-lib/browse.cfm?elib=16768">Listener Preferences For Different Headphone Target Response Curves</a>", presented at the 134th Audio Eng. Soc. Convention, Budapest, Hungary, (May 2013).</li>
<li><span style="font-family: inherit;">Sean E. Olive, Todd Welti and Elisabeth McMullin, "<a href="http://www.aes.org/e-lib/browse.cfm?elib=16874">A Virtual Headphone Listening Test Methodology</a>", presented at the 51st Audio Eng. Soc. International Conference, Helsinki, Finland, (August 2013).</span></li>
<li><span style="font-family: inherit;">Sean E. Olive, Todd Welti and Elisabeth McMullin, "<a href="http://www.aes.org/e-lib/browse.cfm?elib=17042">Listener Preferences for In-Room Loudspeaker and Headphone Target Responses</a>" presented at the 135th Audio Eng. Soc. Convention, New York, USA, (October 2013).</span></li>
<li><span style="font-family: inherit;">Sean E. Olive, "<a href="http://iseat.org/enshowagenda.asp?id=291&BigClass=Abstracts">Do college students prefer the same headphone sound quality as trained listeners</a>?", presented at the 4th ISEAT, Shenzhen, China, (November 2013).</span></li>
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Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com19tag:blogger.com,1999:blog-7172143857693272648.post-6099090318382068232013-12-20T12:06:00.003-08:002013-12-21T10:23:03.402-08:00Harman Kardon factory tour: Pure to the art of sound<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><span style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><a href="http://www.bmwblog.com/2013/12/05/harman-kardon-factory-tour-pure-art-sound/"><img border="0" height="266" src="http://www.bmwblog.com/wp-content/uploads/Harman-Kardon-Shawn-Molnar-31-750x500.jpg" width="400" /></a></span></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><a href="http://www.bmwblog.com/2013/12/05/harman-kardon-factory-tour-pure-art-sound/">Some of the Harman and competitor headphones that we've recently tested.</a></td></tr>
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Giving Harman R&D lab tours and presentations to customers and audio journalists is a part of my job. Recently, we played host to some automotive journalists in town attending the <a href="http://laautoshow.com/">Los Angeles Auto show</a>.<br />
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Automotive audio journalist Shawn Molnar wrote this great article about his visit to our R&D labs that you can read in his popular <a href="http://www.bmwblog.com/2013/12/05/harman-kardon-factory-tour-pure-art-sound/">BMWBlog</a>.<br />
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Shawn gives an overview of his visit to our labs where we showed the journalists our R&D facilities used for testing and evaluating Harman loudspeakers, headphones and automotive audio systems. Most people I meet know Harman for its JBL and Harman Kardon consumer and professional products. They are surprised to lean that 75% of our sales are from <a href="http://www.harman.com/EN-US/Solutions/Home/Pages/AutomotiveBrandedAudio.aspx">Harman branded</a> (JBL, Harman Kardon, Infinity, Lexicon, Mark Levinson) automotive audio and infotainment systems.<br />
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<a href="http://www.ce.org/Research/Products-Services/Research-Library.aspx">Research by CEA</a> has found that consumers now spend almost as much time listening to music in their cars as they do in their homes. Moreover, the audio experiences in the car are increasingly more sonically satisfying than those experienced in the home. Branded audio systems in premium cars typically provide 7-channel surround sound through 16+ loudspeakers that deliver a full-range, balanced, enveloping sound stage that can reach concert sound pressure levels. Compare this to the tinny, spatially bereft stereo speakers in your MacBook Pro or flat panel TV, and you begin to understand why people are listening to music through headphones when they're not listening in their cars.<br />
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So, why don't automotive journalists spend more time writing about audio / infotainment systems in cars given that consumers tell us it's an important factor in their overall satisfaction rating of the car? When reading reviews of new cars, wouldn't it be nice to hear more about the quality of the audio system than how many heated cup holders it has?<br />
<br />Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com3tag:blogger.com,1999:blog-7172143857693272648.post-4633403337297891542013-07-03T13:13:00.003-07:002013-07-03T14:47:12.611-07:00The Science and Marketing of Sound Quality<div class="separator" style="clear: both; text-align: center;">
<a href="http://www.harmaninnovation.com/blog/wp-content/uploads/2013/06/qualitysoundheadphonesheader.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="199" src="http://www.harmaninnovation.com/blog/wp-content/uploads/2013/06/qualitysoundheadphonesheader.jpg" width="400" /></a></div>
<span style="text-align: justify;">To my surprise, this morning an </span><a href="https://twitter.com/InAurem_a2d" style="text-align: justify;">audio friend</a><span style="text-align: justify;"> </span><span style="text-align: justify;">tweeted a link to an article I recently wrote for our company's internal newsletter entitled, "</span><a href="http://www.harmaninnovation.com/blog/the-science-and-marketing-of-sound-quality/" style="text-align: justify;">The Science and Marketing of Sound Quality.</a><span style="text-align: justify;">" My article can be found on a new <a href="http://www.harmaninnovation.com/">Harman Innovation website </a> launched today that features articles on current and future disruptive technology that will impact consumers' infotainment experiences.</span><span style="text-align: justify;"> Check it out.</span><br />
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My article focuses on a longstanding pet peeve of mine (first mentioned in this blog<a href="http://seanolive.blogspot.com/2009/01/what-loudspeaker-specifications-are.html"> posting</a>): The lack of perceptually meaningful loudspeaker and headphone specifications in our industry. While consumer surveys repeatedly report sound quality to be a driving factor in their audio equipment purchases, consumers lack the necessary tools and information to identify the good sounding products from the duds.<br />
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This is particularly true for loudspeakers and headphones where the typical throw-away "10 Hz to 40 kHz" specification provided by the manufacturer is utterly useless. This specification only guarantees that the product makes sound, with no guarantee that the sound is good. While the science exists today to accurately quantify and predict the perceived the sound quality of loudspeakers (and hopefully, soon headphones), the audio industry continues to drag its heels into the 21st century, and not routinely provide this information to consumers.<br />
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A rare exception is JBL Professional who provides comprehensive detailed measurements on studio/broadcast monitors like the new<a href="http://www.jblpro.com/products/recording&broadcast/M2/index.html#.UdSAUhbnnAY"> JBL M2 Master Reference</a> shown below. Inspecting the measured frequency response curves shown below, you can easily recognize the loudspeaker sounds exceptionally neutral and accurate based on the shape (flat, smooth, and extended) Based on this set of measurements, we can predict how a listener would rate the sound quality of the loudspeaker in a controlled listening test, with 86% accuracy. The only pertinent information not shown in this graph is how loud the loudspeaker will play before producing audible distortion (trust me, this loudspeaker will play <i>very loud!</i> )<br />
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Perceptually meaningful loudspeaker specifications like these have been available for almost 30 years! Yet, these specifications are currently not part of any professional and consumer loudspeaker standard. Such a standard would go a long way towards improving the quality and consistency of recorded and reproduced sound. Audio consumers want to hear the truth. We need to provide better information and audio specifications so they can find it.<br />
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<tr><td class="tr-caption" style="text-align: center;"><b>JBL M2 Master Reference Monitor provides true reference sound quality that is clearly indicated by its technical measurements shown below. </b></td></tr>
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<tr><td style="text-align: center;"><a href="http://www.jblpro.com/products/recording&broadcast/M2/images/Tech_R5.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="273" src="http://www.jblpro.com/products/recording&broadcast/M2/images/Tech_R5.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b>The spatially-averaged frequency response curves of the JBL M2 (from top to bottom) for the listening window (green), the first reflections (red), and the total radiated sound power. At the bottom are shown directivity indices of the sound power (dotted blue) and first reflections (dotted red). These measurements tell us that the quality of the direct and reflected sounds produced by the loudspeaker will be very accurate and neutral over a relatively wide listening area.</b></td></tr>
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<br />Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com13tag:blogger.com,1999:blog-7172143857693272648.post-42446870149785636302013-07-01T12:08:00.006-07:002013-07-01T12:19:48.553-07:00Harman Researchers Make Important Headway in Understanding Headphone Response<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="http://www.innerfidelity.com/images/130627_Blog_HarmanVisit_Photo_Main.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" src="http://www.innerfidelity.com/images/130627_Blog_HarmanVisit_Photo_Main.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Todd Welti, Sean Olive and Elisabeth McMullin are shown above with their custom binaural mannequin, "Sidney" wearing a pair of AKG K1000's. No fit or leakage issues with these headphones.</span></td></tr>
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Tyll Hertsens, Chief Editor at <a href="http://www.innerfidelity.com/">Innerfidelity</a> recently visited our research labs in Northridge, and wrote a nice story in his blog about our headphone research and visit to <a href="http://www.harman.com/">Harman</a>. You can read the entire story<a href="http://www.innerfidelity.com/content/harman-researchers-make-important-headway-understanding-headphone-response"> here</a>. <br />
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In his story, Tyll summarizes three of our recent AES papers on headphones, t<a href="http://seanolive.blogspot.com/2013/04/the-relationship-between-perception-and.html">he first one</a> of which I already wrote about in this blog. I hope to write summaries of the other two papers in the upcoming weeks when I can find some free time.</div>
Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com6tag:blogger.com,1999:blog-7172143857693272648.post-53142721999023607452013-04-22T15:25:00.000-07:002013-04-26T06:44:24.415-07:00The Relationship between Perception and Measurement of Headphone Sound Quality<div style="text-align: justify;">
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMIH5X788OppOFHqaum6PzOJ8VJQyo3jQNgn5EENU4zIc1znBfYb-JMAwHfefTmbJlnClec4NwGJ16FM7ksY3GmSz482ycQ9mo1-GGUnHSBpNq4hGkyyS8n66XXgD1ul_gLJQyESRouO8/s1600/HeadphonesTested.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMIH5X788OppOFHqaum6PzOJ8VJQyo3jQNgn5EENU4zIc1znBfYb-JMAwHfefTmbJlnClec4NwGJ16FM7ksY3GmSz482ycQ9mo1-GGUnHSBpNq4hGkyyS8n66XXgD1ul_gLJQyESRouO8/s400/HeadphonesTested.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b>Above: </b>The brands and models of six popular headphones used in this study.</td></tr>
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In many ways, our scientific understanding of the perception and measurement of headphone sound quality is 30 years behind our knowledge of loudspeakers. Over the past three decades, <a href="http://www.amazon.com/Sound-Reproduction-Acoustics-Psychoacoustics-Loudspeakers/dp/0240520092/ref=sr_1_1?ie=UTF8&qid=1366666768&sr=8-1&keywords=Floyd+Toole" target="_blank">loudspeaker scientists</a> have developed controlled listening test methods that provide accurate and reliable measures of listeners' loudspeaker preferences, and their underlying sound quality attributes. From the perceptual data, a set of acoustical loudspeaker measurements has been identified from which we can <a href="http://www.aes.org/e-lib/browse.cfm?elib=12847" target="_blank">model and predict listeners'</a> loudspeaker preference ratings with about 86% accuracy.</div>
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In contrast to loudspeakers, headphone research is still in its infancy. Looking at published acoustical measurements of headphones you will discover there is little consensus among brands (or even within the same brand) on how a headphone should sound and measure [1]. There exists too few published studies based on controlled headphone listening tests to identify which objective measurements and target response curves produce an optimal sound quality. Controlled, double-blind comparative subjective evaluations of different headphones present significant logistical challenges to the researcher that include controlling headphone tactile and visual biases. Sighted biases related to price, brand, and cosmetics have been shown to significantly bias <a href="http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html" target="_blank">listeners judgements of loudspeaker sound quality</a>. Therefore, these nuisance variables must be controlled in order to obtain accurate assessments of headphone sound quality.<br />
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Todd Welti and I recently conducted a study to explore the relationship between the perception and measurement of headphone sound quality. The results were presented at the <a href="http://www.aes.org/events/133/" target="_blank">133rd AES Convention</a> in San Francisco, in October 2012. A PDF of the slide presentation referred to below can be found <a href="http://db.tt/fHSKvbNd" target="_blank">here</a>. The AES preprint can be found in the <a href="http://www.aes.org/e-lib/browse.cfm?elib=16486" target="_blank">AES E-library</a>. The results of this study are summarized below.</div>
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Measuring The Perceived Sound Quality of Headphones</h3>
Double-blind comparative listening tests were performed on six popular circumaural headphones ranging in price from $200 to $1000 (<b><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMIH5X788OppOFHqaum6PzOJ8VJQyo3jQNgn5EENU4zIc1znBfYb-JMAwHfefTmbJlnClec4NwGJ16FM7ksY3GmSz482ycQ9mo1-GGUnHSBpNq4hGkyyS8n66XXgD1ul_gLJQyESRouO8/s1600/HeadphonesTested.png" target="_blank">see above slide</a></b>). The listening tests were carefully designed to minimize biases from known listening test nuisance variables (<b>slides 7-13</b>). A panel of 10 trained listeners rated each headphone based on overall preferred sound quality, perceived spectral balance, and comfort. The listeners also gave comments on the perceived timbral, spatial, dynamic attributes of the headphones to help explain their underlying sound quality preferences. <br />
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The headphones were compared four at a time over three listening sessions <b>(slide 12)</b>. Assessments were made using three music programs with one repeat to establish the reliability of the listeners' ratings. The order of headphone presentations, programs and listening sessions were randomized to minimize learning and order-related biases. The test administrator manually substituted the different headphones on the listener from behind so they were not aware of the headphone brand, model or appearance during the test (<b>slide 8</b>). However, tactile/comfort differences were part of the test. Listeners could adjust the position of the headphones on their heads via light weight plastic handles attached to the headphones.<br />
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Listeners Prefer Headphones With An Accurate, Neutral Spectral Balance</h3>
When the listening test results were statistically analyzed, the main effect on the preference rating was due to the different headphones (<b>slide 15</b>). The preferred headphone models were perceived as having the most neutral, even spectral balance (<b>slide 19</b>) with the less preferred models having too much or too little energy in the bass, midrange or treble regions. Frequency analysis of listeners' comments confirmed listeners' spectral balance ratings of the headphones, and proved to be a good predictor of overall preference (<b>slide 20</b>). The most preferred headphones were frequently described as "good spectral balance, neutral with low coloration, and good bass extension," whereas the less preferred models were frequently described as "dull, colored, boomy, and lacking midrange".<br />
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Looking at the individual listener preferences, we found good agreement among listeners in terms of which models they liked and disliked (<b>slides 16 and 18</b>). Some of the most commercially successful models were among the least preferred headphones in terms of sound quality. In cases where an individual listener had poor agreement with the overall listening panel's headphone preferences, we found either the listener didn't understand the task (they were less trained), or the headphone didn't properly fit the listener, thus causing air leaks and poor bass response; this was later confirmed by doing in-ear measurements of the headphone(s) on individual listeners (<b>slides 26-39</b>).<br />
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<h3>
<b>Measuring the Acoustical Performance of Headphones</b></h3>
Acoustical measurements were made on each headphone using a <a href="http://www.gras.dk/00012/00058/00166/00344/" target="_blank">GRAS 43AG Ear and Cheek</a> simulator equipped with an IEC 711 coupler (<b>slide 24</b>). The measurement device is intended to simulate the acoustical effects of an average human ear including the acoustical interactions between the headphone and the acoustical impedance of the ear. The headphone measurements shown below include these interactions as well as the transfer function of the ear, mostly visible in the graphs as a ~10 dB peak at around 3 kHz. It is important to note that we since we are born with these ear canal resonances, we have adapted to them and don't "hear" them as colorations.<br />
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<h3>
Relationship between Subjective and Objective Measurements </h3>
Comparing the acoustical measurements of the headphones to their perceived spectral balance confirms that the more preferred headphones generally have a smooth and extended response below 1 kHz that is perceived as an ideal spectral balance (<b>slide 25</b>). The least preferred headphones (HP5 and HP6) have the most uneven measured and perceived frequency responses below 1 kHz, which generated listener comments such as "colored, boomy and muffled." The measured frequency response of HP4 shows a slight bass boost below 200 Hz, yet on average it was perceived as sounding thin; this headphone was one of the models that had bass leakage problems for some listeners due to a poor seal on their ears.<br />
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<tr><td><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjH6KjHoGisGTUjiFbVpo7ubD13_cmttCtavXbvgCVw7LRZERZc-ib1ARHNu-c8QdnZ8kYQtJuZvV6V5qx-qdV0EGTPVQB11arRQOkr8OIj5JLoz46HCgRcxrSvLbAJGGVLGfd7svuhtiU/s1600/Objective+Measurements.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="223" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjH6KjHoGisGTUjiFbVpo7ubD13_cmttCtavXbvgCVw7LRZERZc-ib1ARHNu-c8QdnZ8kYQtJuZvV6V5qx-qdV0EGTPVQB11arRQOkr8OIj5JLoz46HCgRcxrSvLbAJGGVLGfd7svuhtiU/s400/Objective+Measurements.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="font-size: 13px;"><b>Above: </b>The left and right channel frequency response measurements of each headphone are shown above the mean preference rating and 95% confidence interval it received in blind listening tests. The dotted green response on each graph shows the "perceived spectral balance" based on the listeners' responses.</td></tr>
</tbody></table>
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<h3>
Conclusions</h3>
In conclusion, this headphone study is one of the first of its kind to report results based on controlled, double-blind listening tests [2]. The results provide evidence that trained listeners preferred the headphones perceived to have the most neutral, spectral balance. The acoustical measurements of the headphone generally confirmed and predicted which headphones listeners preferred. We also found that bass leakage related to the quality of fit and seal of the headphone to the listeners' head/ears can be a significant nuisance variable in subjective and objective measurements of headphone sound quality.<br />
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It is important for the reader not to draw generalizations from these results beyond the conditions we tested. One <a href="http://news.cnet.com/8301-13645_3-57573289-47/how-do-you-like-your-headphone-sound-accurate-or-bassy/" target="_blank">audio writer</a> has already questioned whether headphone sound quality preferences of trained listeners can be extrapolated to tastes of untrained younger demographics whose apparent appetite for bass-heavy headphones might indicate otherwise. We don't know the answer to this question. For younger consumers, headphone purchases may be driven more by fashion trends and marketing B.S. (<b>B</b>efore <b>S</b>cience) than sound quality. While this question is the focus of future research, the preliminary data suggests in <b>blind</b> A/B comparisons kids pref headphones with accurate reproduction to colored, bass-heavy alternatives. This would tend to confirm findings from p<a href="http://seanolive.blogspot.com/2012/05/more-evidence-that-kids-even-japanese.html" target="_blank">revious investigations into loudspeaker preferences</a> of high school and college students (both Japanese and American) that so far indicates most listeners prefer accurate sound reproduction regardless of age, listener training or culture.<br />
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Future headphone research may tell us (or not) that most people prefer accurate sound reproduction regardless of whether the loudspeakers are installed in the living room, the automobile, or strapped onto the sides of their head. It makes perfect sense, at least to me. Only then will listeners hear the truth -- music reproduced as the artist intended.<br />
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<b>Footnotes</b><br />
<b>[1]</b> Despite the paucity of good subjective measurements on headphones there does exist some online resources where you can find objective measurements on headphones. You will be hard pressed to find a manufacturer who will supply these measurements of their products. The resources include <a href="http://headphone.com/">Headroom.com</a>, <a href="http://www.soundandvisionmag.com/category/site-channel/gear/headphones" target="_blank">Sound & Vision Magazine</a>, and <a href="http://innerfidelity.com/">InnerFidelity.com</a>. Tyll Hertsens at InnerFidelity has a <a href="http://www.innerfidelity.com/images/AllGraphs.pdf">large database</a> of frequency response measurements of headphones that clearly illustrate the lack of consensus among manufacturers on how a headphone should sound and measure. There is even a lack of consistency among different models made by the same brand.<br />
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<b>[2]</b> Sadly, studies like this present one are so uncommon in our industry that <a href="http://www.soundandvisionmag.com/blog/2012/12/31/biggest-audio-story-2012" target="_blank">Sound and Vision Magazine</a> recently declared this paper as the biggest audio story in 2012. Hopefully that will change sooner than later.<br />
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Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com60tag:blogger.com,1999:blog-7172143857693272648.post-3318650356873563812012-11-30T23:05:00.003-08:002012-12-01T11:54:51.639-08:00Behind Harman's Testing LabThis past week I had an enjoyable time meeting well-known technology writer <a href="http://en.wikipedia.org/wiki/Robert_Scoble" target="_blank">Robert Scoble</a> who was visiting our Harman facilities in Northridge, CA along with his geek-in-command <a href="http://soundcloud.com/scobleizer/meeting-audio-geeks-at-jbl" target="_blank">Sam Levin</a>e. As part of the tour, I showed them our <a href="http://seanolive.blogspot.com/2009/05/harman-international-reference.html" target="_blank">Reference Listening Room </a>and <a href="http://seanolive.blogspot.com/2010/07/harman-kardons-quest-to-standardise.html" target="_blank">Multichannel Listening Lab</a> where we do product research and double-blind evaluations of loudspeakers. We discussed the science and philosophy behind how we design and measure the sound quality of our products.<br />
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<iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.youtube.com/embed/56xPMqZmejU?feature=player_embedded' frameborder='0'></iframe></div>
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One of the topics of discussion was my <a href="http://seanolive.blogspot.com/2012/05/more-evidence-that-kids-even-japanese.html" target="_blank">recent research</a> that explores whether high school and college students from USA and Japan have different tastes and preferences in the quality of reproduced sound compared to older trained listeners. We talked about <a href="http://seanolive.blogspot.com/2008/12/part-2-differences-in-performances-of.html" target="_blank">differences in the tastes and performances</a> of trained versus untrained listeners, and how Harman is able to accurately predict <a href="http://www.aes.org/e-lib/browse.cfm?elib=12794" target="_blank">subjective preference rating</a>s of loudspeakers based on<a href="http://www.aes.org/e-lib/browse.cfm?elib=12847" target="_blank"> a predictive model </a>that analyzes a set of comprehensive anechoic measurements.<br />
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After running Robert and Sam through a few trials of listener training using our software <a href="http://harmanhowtolisten.blogspot.com/2011/01/welcome-to-how-to-listen.html" target="_blank">"How to Listen"</a>, I decided to put them through a couple of double-blind listening test trials to see if they had the right stuff. They compared four different brands of floor-standing loudspeakers located behind an acoustically transparent, visually opaque curtain where each loudspeaker is shuffled into the same position via an automated speaker shuffler. All of our tests are conducted double-blind because we have found that even trained listeners are influenced by <a href="http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html" target="_blank">nuisance variables</a> such as brand, price, size, etc.<br />
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In these tests Robert and Sam heard the same four loudspeakers that have been evaluated previously by hundreds of untrained listeners including young, old, American, Asian, and European listeners, whose preferences and performances were compared to those of our panel of trained listeners. From these tests, we have found evidence that most listeners prefer the most accurate, neutral loudspeaker regardless of age, culture or listening experience.<br />
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When the listening trials were done, the curtain went up, and Robert and Sam were surprised to discover their favorite choice was the most accurate loudspeaker which was the least expensive. The science works. One of the speakers Robert didn't like was a model that he actually owned: it had excessive amounts of treble and upper bass, which I'm told is mandated by the manufacturer's marketing department who believe that "boom and tizz" are what their customers want. Luckily, I haven't met many of their customers, yet. Robert, then surprised me by turning on his camera doing an impromptu interview, which hopefully you'll enjoy. If you want to learn more about the engineering process and tools behind designing a speaker, check out the interview with one of our speaker engineering stars,<a href="http://www.youtube.com/watch?v=WUuMQY9yBOI" target="_blank"> Charles Sprinkle</a>.<br />
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In my next blog posting I hope to discuss some of the exciting research we've been doing on the relationship between the <a href="http://www.aes.org/e-lib/browse.cfm?elib=16486" target="_blank">perception and measurement of headphone sound quality</a>. The goal is to develop the same science for measuring and predicting the sound quality of headphones that we've found useful for designing good sounding loudspeakers. Stay tuned!<br />
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<br />Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com10tag:blogger.com,1999:blog-7172143857693272648.post-86683039647881550792012-05-10T07:32:00.001-07:002012-06-04T09:05:57.614-07:00More Evidence that Kids (American and Japanese) Prefer Accurate Sound Reproduction<div class="separator" style="clear: both; text-align: center;">
<iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.youtube.com/embed/gsVO2PAp8M8?feature=player_embedded' frameborder='0'></iframe></div>
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<span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;">Geoffrey Morrison, an audio writer at CNET and Sound & Vision has posted a </span><span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;"><a href="http://www.soundandvisionmag.com/blog/2012/05/09/kids-are-alright" target="_blank">nice summary</a></span><span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;"> of my latest AES paper "</span><span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;"><a href="http://www.aes.org/events/132/papers/?ID=3050" target="_blank">Some New Evidence that Teenager and College Students May Prefer Accurate Sound Reproduction</a></span><span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;">" presented at the recent 132nd AES Convention in Budapest, Hungary.</span><br />
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<span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;">The paper is available for download here at the <a href="http://www.aes.org/e-lib/browse.cfm?elib=16321" target="_blank">AES E-library</a>, and I have provided a YouTube video and a <a href="http://db.tt/eZ7HGbaw" target="_blank">PDF </a>of my presentation slides that summarize the main points of the research.</span><br />
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<span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="color: #363636; line-height: 19px;"> The abstract of the paper reads as follows:</span></span><br />
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<span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="color: #363636; line-height: 19px;"><i>A group of 58 high school and college students with different expertise in sound evaluation participated in two separate controlled listening tests that measured their preference choices between music reproduced in (1) MP3 (128 kbp/s) and lossless CD-quality file formats, and (2) music reproduced through four different consumer loudspeakers. As a group, the students preferred the CD-quality reproduction in 70% of the trials and preferred music reproduced through the most accurate, neutral loudspeaker. Critical listening experience was a significant factor in the listeners’ performance and preferences. Together, these tests provide some new evidence that both teenagers and college students can discern and appreciate a better quality of reproduced sound when given the opportunity to directly compare it against lower quality options.</i></span></span><span class="Apple-style-span" style="font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="color: #363636; line-height: 19px;"> </span></span><br />
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<span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;">The effects of</span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;"> </span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;"><a href="http://seanolive.blogspot.com/2010/07/are-there-cross-cultural-preferences-in.html" target="_blank">culture</a></span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;"> </span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;">and</span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;"><a href="http://seanolive.blogspot.com/2008/12/part-2-differences-in-performances-of.html" target="_blank"> trained versus untrained listeners</a></span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;"> </span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;">on loudspeaker preference are topics that have been discussed in previous postings on Audio Musings. To further shed some light on this topic, </span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="line-height: 19px;">I also ran 149 native speaking Japanese college students through the same loudspeaker preference test along with 12 Harman trained listeners. The graph below shows the mean loudspeaker preference ratings for these two groups of listeners along with the four different groups of high school and college students from Los Angeles. </span></span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlZ07terdDrb5wpLfb5Wt04cf353Uk2HHK5H8L-nZyMce7KrhLrLLS6dm1hfVQYeV3eyPsh-evjKJuxOUyqtKfSrFZiKj9XrWeuKB6Pl8-WP_pXBNDFLF3ytqStGbYEcvKFuXa2OZRdeA/s1600/Individual+Listener+Loudspeaker+Preferences.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlZ07terdDrb5wpLfb5Wt04cf353Uk2HHK5H8L-nZyMce7KrhLrLLS6dm1hfVQYeV3eyPsh-evjKJuxOUyqtKfSrFZiKj9XrWeuKB6Pl8-WP_pXBNDFLF3ytqStGbYEcvKFuXa2OZRdeA/s400/Individual+Listener+Loudspeaker+Preferences.png" width="400" /></a></div>
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<span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="line-height: 19px;">Not surprising, (at least to me) I found that the Japanese college students on average preferred the same accurate loudspeaker (A) as did the 58 Los Angeles students, and the trained Harman listening panel. The main differences among the different listening groups were related to the effect of prior critical listening experience: the more trained listeners simply rated the loudspeakers lower on the preference scale, and were more discriminating and consistent in their responses. This result is consistent with previous <a href="http://www.nytimes.com/2010/05/10/business/media/10audio.html?_r=1" target="_blank">studies</a>. The least preferred and least accurate loudspeaker (Loudspeaker D) generated the most variance in ratings among the different listening groups. This was explained by its highly directional behavior combined with its inconsistent frequency response as you move from on-axis to off-axis seating positions. This meant that listeners sitting off-axis heard a much different (and apparently better quality) sound than those listeners sitting on-axis.</span></span><br />
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<span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="line-height: 19px;"> </span></span><span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif; line-height: 19px;">While the small sample size of listeners doesn't allow us to make generalizations to larger populations, nonetheless it is reassuring to find that both the American and Japanese students, regardless of their critical listening experience, recognized good sound when they heard it, and preferred it to the lower quality options.</span><br />
<span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="line-height: 19px;"><br /></span></span><br />
<span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="line-height: 19px;">It would appear that the reason kids don't own better sounding audio solutions has nothing to do with their supposed "deviant" tastes in sound quality, but more do with other factors (e.g. price, convenience, portability, marketing, fashion) that have nothing to do with sound quality. Music and audio companies should take notice that kids can indeed discriminate between good and bad sound, and prefer accurate sound, despite what the <a href="http://www.nytimes.com/2010/05/10/business/media/10audio.html?_r=1" target="_blank">media </a>has been falsely reporting for the last few years. With that out of the way, we should focus on figuring out how to sell sound quality to kids at affordable prices and form factors they desire to own.</span></span><br />
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<span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="line-height: 19px;">The research suggests that if we cannot figure out how to sell better sound to kids, we have no one to blame but ourselves. </span></span><br />
<span class="Apple-style-span" style="color: #363636; font-family: Georgia, 'Times New Roman', serif;"><span class="Apple-style-span" style="line-height: 19px;"><br /></span></span>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com29tag:blogger.com,1999:blog-7172143857693272648.post-67640911510264330762011-10-06T13:16:00.000-07:002011-10-06T13:23:14.137-07:00Harman Science of Sound Demonstrations at Rocky Mountain Audio Fest 2011<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1To4xpkyLk1Uig3fPwVxnuWg4EST_PcUQFMAAjF8EgByWqePaYqtJOWaqkOWstKITmDBCp0Vv5KRX5QyDH056JbsAwpMUJa6oUZv9SUywZHS2a6z2NOTNfUCzYWESLBpTKYVTVA1WsPs/s1600/Science+of+Sound+by+Harman.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1To4xpkyLk1Uig3fPwVxnuWg4EST_PcUQFMAAjF8EgByWqePaYqtJOWaqkOWstKITmDBCp0Vv5KRX5QyDH056JbsAwpMUJa6oUZv9SUywZHS2a6z2NOTNfUCzYWESLBpTKYVTVA1WsPs/s640/Science+of+Sound+by+Harman.png" width="412" /></a></div>
October 14-16, I will be giving<b> Science of Sound</b> presentations for the Harman Luxury Audio Group (room #8020) at the <a href="http://audiofest.net/2011/index.php">Rocky Mountain Audio Fest (RMAF)</a> in Denver, CO. My demonstration will be repeated every 1/2 hour on the hour and half-hour.<br />
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Drop by and find out more about the science behind Harman audio product development and testing including<a href="http://www.jblsynthesis.com/"> JBL</a> and <a href="http://www.revelspeakers.com/">Revel</a> loudspeakers. I will be demonstrating our latest release of the <a href="http://harmanhowtolisten.blogspot.com/">"How to Listen"</a> software used for training and selecting listeners for product research and testing. Find out how discriminating and reliable you are as a critical listener.<br />
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Attendees will be given 30% discount coupons towards a copy of Floyd Toole's book <a href="http://www.amazon.com/Sound-Reproduction-Acoustics-Psychoacoustics-Loudspeakers/dp/0240520092">"Sound Reproduction"</a> (Focal Press), a book that describes much of the current scientific knowledge and perception of the sound quality of loudspeakers, listening rooms, and their acoustical interaction with each other. I will be raffling off a few copies to the best performing listeners.<br />
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I hope to see you there!<br />
<br />Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com8tag:blogger.com,1999:blog-7172143857693272648.post-79722957565485410282011-04-21T11:43:00.000-07:002011-04-21T12:23:37.934-07:00Topics Related to Perception and Measurement of Reproduced Sound<div class="separator" style="clear: both; text-align: center;"><a href="http://www.aes.org/sections/la/assets/AES5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="110" src="http://www.aes.org/sections/la/assets/AES5.jpg" width="400" /></a></div><div style="font: 12.0px Helvetica; margin: 0.0px 0.0px 0.0px 0.0px;"><br /></div><div style="font: 12.0px Helvetica; margin: 0.0px 0.0px 0.0px 0.0px;"><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">On Tuesday, April 26th 2011, I will be giving a presentation at the meeting of the Los Angeles AES Chapter on several topics related to recent audio research at Harman International. The topics include:</span></span></div><div style="font: 12.0px Helvetica; margin: 0.0px 0.0px 0.0px 0.0px;"></div><ul><li><a href="http://seanolive.blogspot.com/2010/06/some-new-evidence-that-generation-y.html"><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">Preference in Quality of Reproduced Sound Among Generation Y</span></a><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;"> </span></li><li><a href="http://seanolive.blogspot.com/2010/07/are-there-cross-cultural-preferences-in.html"><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">Are There Cross-Cultural Preferences in Quality of Reproduced Sound?</span></a></li><li><a href="http://seanolive.blogspot.com/2009/11/subjective-and-objective-evaluation-of.html"><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">The Subjective and Objective Evaluation of Room Correction Products</span></a></li><li><a href="http://seanolive.blogspot.com/2010/12/how-to-listen-course-on-how-to.html"><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">Harman's How to Listen: A Software program for Training Listeners</span></a></li></ul><div><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;"><br /></span></div><div><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">I've briefly discussed these topics in Audio Musings over the past few months, and you can find summaries of them by clicking on the links above. I'll be giving an update on new findings, and briefly touch on topics not mentioned above. As a door prize, Harman will donate a free copy of Dr. Floyd Toole's book </span><b><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">Sound Reproduction</span></b><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;"> (shown on the right side bar) autographed by the author of the book.</span></div><div><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;"><br /></span></div><div><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">AES members and nonmember guests are welcome to attend. The meeting will be held at the Sportmen's Lodge in Studio City. More details can be found at the</span><a href="http://www.aesla.org/"><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;"> Los Angeles AES website</span></a><span class="Apple-style-span" style="font-family:Times, 'Times New Roman', serif;">.</span></div>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com4tag:blogger.com,1999:blog-7172143857693272648.post-6895835536804277142011-04-03T17:24:00.000-07:002011-04-03T17:26:49.395-07:00Version 2.04 of Harman How to Listen Now Available For Download!<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTeKVXHNZ7Gbr-XGYCUsSAtxvQKVQhcCL2DQi1UoAzI0IA3jHQMkMHz5IeIpQhOd42t78Xug3z1fZ_eAseUaNv-inwcDssTOTT3oHb9eGha1R3RObtqTMeGo_hyOUTnxATJhnZC-GGQVo/s1600/BandID+With+Harman+Skin.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTeKVXHNZ7Gbr-XGYCUsSAtxvQKVQhcCL2DQi1UoAzI0IA3jHQMkMHz5IeIpQhOd42t78Xug3z1fZ_eAseUaNv-inwcDssTOTT3oHb9eGha1R3RObtqTMeGo_hyOUTnxATJhnZC-GGQVo/s400/BandID+With+Harman+Skin.png" width="400" /></a></div>Version 2.04 of Harman How to Listen is now available for download <a href="http://harmanhowtolisten.blogspot.com/2011/01/welcome-to-how-to-listen.html">here.</a><br /><br />This update fixes the problem with the noise and hum attribute tests. We've also updated the <a href="https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B97zTRsdcJTfMjI5ZjQ1OWMtZTZmYS00OTliLWJhZTQtZmVkMmExMWIyNDkw&hl=en">user's manual</a> to help navigate around some installation issues some users have reported.Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com12tag:blogger.com,1999:blog-7172143857693272648.post-30021390872772492882011-03-25T15:19:00.000-07:002011-03-25T15:19:41.481-07:00Version 2.03 of Harman How to Listen Now Available For Download!<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioK_jLTIPO9lpmAv1bmJ8TjSDqsuoyoql-3Y_qwZVhzidcmXvwlTfPgCh7qfkp1e8br2BgAhkEjwy_cconz0WdDkHf0s4BKR6hNXUbwDf5EZh2Qb6b431xNUZUVXthK4lu3VuNxhnPmIQ/s1600/AttributeTask500w.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioK_jLTIPO9lpmAv1bmJ8TjSDqsuoyoql-3Y_qwZVhzidcmXvwlTfPgCh7qfkp1e8br2BgAhkEjwy_cconz0WdDkHf0s4BKR6hNXUbwDf5EZh2Qb6b431xNUZUVXthK4lu3VuNxhnPmIQ/s1600/AttributeTask500w.png" /></a></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: justify;">You can download the latest update of Harman How to Listen (version 2.03) <a href="http://harmanhowtolisten.blogspot.com/2011/01/welcome-to-how-to-listen.html">here.</a> This update fixes a bug in the Windows version that prompted listeners to locate program material that was not packaged with the installer. There is no significant change to the Mac version. Enjoy!</div>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com0tag:blogger.com,1999:blog-7172143857693272648.post-47937801996476638082011-03-15T00:16:00.000-07:002011-03-15T00:28:14.446-07:00Harman's "How to Listen" Listener Training Software Now Available as Beta<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTeKVXHNZ7Gbr-XGYCUsSAtxvQKVQhcCL2DQi1UoAzI0IA3jHQMkMHz5IeIpQhOd42t78Xug3z1fZ_eAseUaNv-inwcDssTOTT3oHb9eGha1R3RObtqTMeGo_hyOUTnxATJhnZC-GGQVo/s1600/BandID+With+Harman+Skin.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTeKVXHNZ7Gbr-XGYCUsSAtxvQKVQhcCL2DQi1UoAzI0IA3jHQMkMHz5IeIpQhOd42t78Xug3z1fZ_eAseUaNv-inwcDssTOTT3oHb9eGha1R3RObtqTMeGo_hyOUTnxATJhnZC-GGQVo/s400/BandID+With+Harman+Skin.png" width="400" /></a></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div><br />
</div>Well, it's been some time coming, but the listener training software <a href="http://seanolive.blogspot.com/2010/12/how-to-listen-course-on-how-to.html">Harman How to Listen</a> is finally available for free download <a href="http://harmanhowtolisten.blogspot.com/2011/01/welcome-to-how-to-listen.html">here</a>. This beta software is available in both Mac OSX and Windows versions.<br />
<div><br />
</div><div>We are pleased to offer the software packaged with four high quality music samples, courtesy of <a href="http://bravurarecords.com/">Bravura Records.</a> The 24-bit music tracks are provided in both 96 kHz and 48 kHz formats in order to be compatible with older PC sound cards. We hope you try the software, and find that it improves you critical listening skills. This is a work in progress, and we expect to add more features and training tasks to this public version of the software over time. Enjoy!</div>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com41tag:blogger.com,1999:blog-7172143857693272648.post-56041311571844507492010-12-09T11:58:00.001-08:002010-12-10T11:23:11.752-08:00How to Listen: A Course on How to Critically Evaluate the Quality of Recorded and Reproduced Sound<i><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;">Next month, I will be giving a one day course on</span><b><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;"> How to Listen</span></b><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;"> at the </span><a href="http://www.almainternational.org/index.php?option=com_content&view=article&catid=19:default&id=32:winter-symposium-program-2011"><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;">2011 ALMA Winter Symposium</span></a><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;"> in Las Vegas,held Jan. 4th and 5th, just prior to the CES show. The symposium will also feature other courses, workshops and paper sessions on loudspeaker and headphone design, testing and evaluation. You can register for my course and other events at the ALMA Symposium </span><a href="https://almin.memberclicks.net/index.php?option=com_mc&view=mc&mcid=form_88701"><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;">here</span></a><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;">. Below is a brief preface for my course How to Listen, which I encourage you to attend.</span></i><br /><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;"></span><br /><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;"><hr /><table class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;" align="center" cellpadding="0" cellspacing="0"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVSchEdNpHqOgODoa9-mDxsJJZTo8LCFXwVwnzAXH28ztN88zTAbvyKHx0O9cQ4FCfM_R0RsgFXPL4ie0su9NM36MmEr2TW6D8Wig5AFgx6YnlrSQtVO6Ei5wY9LEk5d3nfsWYLB8MZWI/s1600/SeanHessTraining+in+Ref.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVSchEdNpHqOgODoa9-mDxsJJZTo8LCFXwVwnzAXH28ztN88zTAbvyKHx0O9cQ4FCfM_R0RsgFXPL4ie0su9NM36MmEr2TW6D8Wig5AFgx6YnlrSQtVO6Ei5wY9LEk5d3nfsWYLB8MZWI/s400/SeanHessTraining+in+Ref.png" border="0" width="400" height="265" /></span></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;">Figure 1: </span></span><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;">A listener training in the Harman International Reference Listening Room using the original version of the </span></span><b><i><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;">How to Listen</span></span></i></b><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;"> training software.</span></span></td></tr></tbody></table><span class="Apple-style-span" style="font-family:arial;"><br /></span></span><br /><div><div style="text-align: justify;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" >Whether you are involved in the mixing of live and recorded sound, the design and calibration of sound systems, or just shopping for a new audio system, the question “Does it sound good?” is usually foremost on your mind. With sufficient prodding, most people can offer an opinion on the overall sound quality of a recording and its reproduction. Beyond that, listeners generally lack the necessary experience, training and vocabulary to describe which specific aspects of the sound they like and dislike. Sadly, the audio industry has no standardized terminology that allows musicians, audio engineers and audiophiles to communicate with each other about sound quality in a concise and meaningful way. Courses in critical listening are not commonly available in audio programs at universities, and are even less available to the general public. In summary, there is a real need for a comprehensive course that teaches audio enthusiasts how to critically evaluate sound quality.</span></div><span class="Apple-style-span" style="font-family:'Trebuchet MS',sans-serif;"><div><div><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></span></span></div><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;"><span class="Apple-style-span" style="font-size:small;"></span></span></span></div><b><span class="Apple-style-span" style="font-size:large;"><span class="Apple-style-span" style="font-family:arial;">A Scientific Approach Towards Training Listeners</span></span></b><span class="Apple-style-span" style="font-family:arial;"><br /></span><div style="text-align: justify;"><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;">T<span style="font-size:small;">o address this need, the author has developed a critical listening course called </span></span><span style="font-size:small;"><b><i><span class="Apple-style-span" style="font-family:arial;">How to Listen</span></i></b></span><span class="Apple-style-span" style=";font-family:arial;font-size:small;" >. The course aims to teach students how to evaluate sound quality using percepts well established in the auditory perception field. These sound quality percepts are taught and demonstrated in a controlled way using real-time processing of recorded sounds. This has two benefits. First, the intensity of each attribute can be adjusted according to the aptitude and performance of the listener. Second, closely tying the physical properties of the stimulus to its perception and evaluation (a science known as psychoacoustics) there is theoretical basis behind the training approach. For example, the listener training data can be used to better understand how we perceive sound quality, which physical aspects of sound matter most of its perceived quality, and possibly identify the important underlying sound quality attributes that influence our preferences. Critical listening is treated as a science, rather than the black art it currently is.</span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px; text-align: justify;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span style="letter-spacing: 0px;"></span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><b><i><span class="Apple-style-span" style="font-family:arial;">How to Listen</span></i></b><span class="Apple-style-span" style="font-family:arial;"> also includes classroom topics in the fundamentals of human auditory perception, sound quality research in variables that significantly influence the quality of recorded and reproduced sound (e.g. loudspeakers, rooms, recordings, microphones) and a brief tutorial in how to conduct sound quality listening tests that produce accurate, reliable and valid results. </span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px; text-align: justify;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span style="letter-spacing: 0px;"></span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">But before we get too far ahead of ourselves, there must be good reasons for training listeners since it requires an investment in time and resources. There is also the question of external validity: Can the sound quality preferences of trained listeners be extrapolated to the preferences of untrained listeners, and does this hold true across different cultures? These questions will be answered in the following sections.</span></span></div><div style="font: 12px Helvetica; margin: 0px; min-height: 14px; text-align: justify;"><span class="Apple-style-span" style="font-family:arial;"><span style="letter-spacing: 0px;"></span></span></div><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:130%;" ><b><span class="Apple-style-span"><span class="Apple-style-span" style="font-family:arial;">Why Train Listeners?</span></span></b></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">There are several compelling reasons for training listeners. First, trained listeners have been shown to produce more discriminating and reliable judgment of sound quality than untrained listeners [1]. Fewer listener can be used to achieve a similar level of statistical confidence, which can result in savings in time and money. For example, a panel of 15 trained listeners can provide sound quality ratings with reliable statistical confidence in less than 8 hours. To achieve a similar level of confidence using untrained listeners would require about 10 times more listeners, 10 times more days to complete the testing, and cost 10 times more money to pay the listeners and staff conducting the tests. If the study is conducted by an independent research firm using 200-300 untrained listeners, the cost can easily exceed $100k.</span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px; text-align: justify;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span style="letter-spacing: 0px;"></span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">A second reason for training listeners is that they are able to report precisely what they like and dislike about the sound quality using well-defined, meaningful terms. This feedback can provide important guidance for reengineering the product for optimal sound quality.</span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px; text-align: justify;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span style="letter-spacing: 0px;"></span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">Besides training listeners for product research, there are benefits in training audio marketing and sales people to become better critical listeners. Training makes them better equipped to communicate sound quality issues to audio engineers and customers. As audio companies expand sales and operations in China, India, and other developing countries, there is a growing need to develop a common cross-cultural understanding as to what constitutes good sound and unacceptable sound.</span></span></div><div style="font: 12px Helvetica; margin: 0px; min-height: 14px; text-align: justify;"><span class="Apple-style-span" style="font-family:arial;font-size:130%;"><span style="letter-spacing: 0px;"></span></span></div><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:130%;" ><b><span class="Apple-style-span"><span class="Apple-style-span" style="font-family:arial;">Does Training Bias Listeners?</span></span></b></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">An important question is whether the training process itself biases the sound quality preferences of listeners. If the trained listener preferences are different from those of the targeted demographic, there is a danger the product may not be well received in the marketplace. This raises the age old question, “Is preference in sound quality a matter of personal taste - much like food, wine and music - or is it universal?” </span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px; text-align: justify;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span style="letter-spacing: 0px;"></span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">To study this question, the author compared the performances and loudspeaker preferences of trained listeners versus untrained listeners [1]. Over 300 untrained listeners were tested over a period of 18 months where they compared four different loudspeakers under controlled, double-blind listening conditions. Their preferences were then compared to the preferences of the trained Harman listening panel. </span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px; text-align: justify;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span style="letter-spacing: 0px;"></span></span></div><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">The results, plotted in Figure 2, show that the rank ordering of the loudspeaker preferences were the same for both the trained and untrained listeners. There were two main differences in how the two groups of listeners responded. First, the trained listeners tended to give lower loudspeaker ratings overall. Second, the trained listeners distinguished themselves from the untrained listeners by generally giving more discriminating and consistent loudspeaker preference ratings.</span></span><span class="Apple-style-span" style="font-family:arial;font-size:100%;"><br /></span><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></span><span class="Apple-style-span" style="font-family:arial;"><br /></span><br /><table class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;" align="center" cellpadding="0" cellspacing="0"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0HqDpEpS8tohyphenhyphenacOYqo7bpau9KXL-r8jJc1bDRdTrSPS-yFJpr0MqBg76nEEHoAl58tWUkEvmS6313LoX-STsscWqV24BokSPNF1bLMS6pm3X4_r-7cqXnfaSVAKGFOrozriaPnFaCVw/s1600/TrainedvsUntrained.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span class="Apple-style-span" style="font-family:arial;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0HqDpEpS8tohyphenhyphenacOYqo7bpau9KXL-r8jJc1bDRdTrSPS-yFJpr0MqBg76nEEHoAl58tWUkEvmS6313LoX-STsscWqV24BokSPNF1bLMS6pm3X4_r-7cqXnfaSVAKGFOrozriaPnFaCVw/s400/TrainedvsUntrained.png" border="0" width="400" height="302" /></span></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;">Figure 2: The mean loudspeaker preference ratings and 95% confidence intervals are shown for four loudspeakers evaluated in a controlled, double-blind listening test. The results of different groups of untrained listeners are compared to those of the 12 Harman listeners.</span></span></td></tr></tbody></table><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></span></div><div><b><span class="Apple-style-span" style="font-family:arial;"><span class="Apple-style-span" style="font-size:medium;">Relative Performances of Trained Versus Untrained Listeners </span></span></b></div><div><span class="Apple-style-span" style="font-family:arial;font-size:100%;"><span class="Apple-style-span">A common performance metric used to quantify the listener’s discrimination and consistency in rating sound quality is the F-statistic. This calculation is done by performing an analysis of variance (ANOVA) on the main variable being tested. In the above study [1], the performances of trained versus untrained listeners were compared by calculating the loudspeaker F-statistic for each individual listener. </span></span><span style="font-weight: bold;font-size:100%;" ><br /></span><span style="font-weight: bold;font-family:arial;font-size:100%;" class="Apple-style-span" ><br /></span><span style="letter-spacing: 0px;"><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">Figure 3 shows the relative performance of different groups of untrained listeners based on their mean F-statistics </span><i><span class="Apple-style-span" style="font-family:arial;">compared to </span></i><span class="Apple-style-span" style="font-family:arial;">the F-statistics of the trained listeners. The relative performances of the untrained groups were: audio retailers (35%), audio reviewers (20%), audio marketing/sales staff (10%), and college students (4%). The poor performance of the students was explained by their tendency to give all four loudspeakers very similar and high ratings. A likely explanation for this was that they experienced a level of sound quality that was much higher than their everyday common experience: compressed MP3 music reproduced through headphones. The good news is that the students seemed to appreciate the higher fidelity sound based on the high ratings. In time, they will hopefully seek out better quality audio systems. </span></span><span class="Apple-style-span" style="font-family:arial;font-size:100%;"><br /></span><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></span><span class="Apple-style-span" style="font-family:arial;"><br /></span><br /><table class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;" align="center" cellpadding="0" cellspacing="0"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEif5-1oyIRkAAOnZ6OMINL9OaijMMycqeLCS7iUh39m6dYa2blvJbP2hv5d6SiddFT4gHl9oV6v9LpebooJpV5icaIzJ66k9zPesL4_LD9_myccf-GOw9nN-uSPIJ4jE_Nv2DxuCoVbSEE/s1600/Trained+vs+UnTrained+Performance2.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span class="Apple-style-span" style="font-family:arial;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEif5-1oyIRkAAOnZ6OMINL9OaijMMycqeLCS7iUh39m6dYa2blvJbP2hv5d6SiddFT4gHl9oV6v9LpebooJpV5icaIzJ66k9zPesL4_LD9_myccf-GOw9nN-uSPIJ4jE_Nv2DxuCoVbSEE/s400/Trained+vs+UnTrained+Performance2.png" border="0" width="400" height="225" /></span></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;">Figure 3: </span></span><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;">The relative performance of different groups of untrained listeners compared to the trained Harman listeners. Performance is based on the group’s average loudspeaker F-statistic which represents their ability to give discriminating and consistent preference ratings.</span></span></td></tr></tbody></table><div><span style="letter-spacing: 0px;font-size:130%;" ><span class="Apple-style-span" style="font-family:arial;"><br /></span></span></div><span style="font-size:130%;"><b><span class="Apple-style-span"><span class="Apple-style-span" style="font-family:arial;">Are There Cross-Cultural Preferences in Sound Quality?</span></span></b></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">One of the oldest controversies in audio is the notion that different cultures or geographical regions of the world have different sound quality preferences [</span><a href="http://seanolive.blogspot.com/2010/07/are-there-cross-cultural-preferences-in.html"><span class="Apple-style-span" style="font-family:arial;">see reference 2</span></a><span class="Apple-style-span" style="font-family:arial;">]. For example, it is often claimed that Japanese listeners have different loudspeaker preferences than Americans due to differences in language, music, cultural practices and norms, and the acoustics of their homes. So far, very little formal research has done on this subject. In some preliminary studies, the author has found no significant differences in sound quality preferences for loudspeakers and automotive audio systems among Chinese, Japanese and American listeners.</span></span></div><div style="font: 12px Helvetica; margin: 0px; min-height: 14px; text-align: justify;"><span class="Apple-style-span" style="font-family:arial;"><span style="letter-spacing: 0px;"></span></span></div><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:130%;" ><b><span class="Apple-style-span"><span class="Apple-style-span" style="font-family:arial;">How to Listen: A New Listener Training Software Application</span></span></b></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">Research has found most sound quality percepts fall under the attribute categories of timbre, spatial, dynamic or related nonlinear distortion. Within these four attributes there are additional sub-attributes that describe more specific sonic characteristics of the attribute. For example, </span><b><i><span class="Apple-style-span" style="font-family:arial;">Bright-Dull</span></i></b><span class="Apple-style-span" style="font-family:arial;"> and </span><b><i><span class="Apple-style-span" style="font-family:arial;">Full-Thin</span></i></b><span class="Apple-style-span" style="font-family:arial;"> are timbre sub-attributes related to the relative emphasis and de-emphasis of high and low frequencies, respectively. Sub-attributes for spatial quality deal with the location and width of the auditory image(s), and the perceived sense of spaciousness or envelopment. Distortion sub-attributes include the presence of noise, hum, audible clipping and distortions specific to the audio device(s) under test.</span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px; text-align: justify;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:100%;" ><span style="letter-spacing: 0px;"></span></span></div><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><b><i><span class="Apple-style-span" style="font-family:arial;">How to Listen</span></i></b><span class="Apple-style-span" style="font-family:arial;"> focuses on teaching listeners to evaluate sound quality differences based on these four attributes and their sub-attributes (see Figure 4). While listening to music recordings, one or more attributes are manipulated in a controlled way so that listeners recognize and report the magnitude of these changes using the appropriate terms and scales. An analogy to this would the </span><a href="http://www.winearomawheel.com/"><span style="text-decoration: underline;"><span class="Apple-style-span" style="font-family:arial;">Wine Aroma Wheel</span></span></a><span class="Apple-style-span" style="font-family:arial;"> where expert wine tasters are trained to identify the intensities of different aroma-flavors perceived in the wine.</span></span><span class="Apple-style-span" style="font-family:arial;"><br /></span><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></span><span class="Apple-style-span" style="font-family:arial;"><br /></span><br /><table class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;" align="center" cellpadding="0" cellspacing="0"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2e-KxVJsK_PyZ9VhK69mEPptDzZlbnU1whHhHEYTXKM4Jy_Vc4UXkJIC8CQ6pRRdQMIHBkV_DGBQH_An6A8ROXoXj_McRcvdBXZhet82mgfZI76_n5oUaY2pEo9UY_qtvTvAgmeIJM2M/s1600/Listener+Training+Tasks.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span class="Apple-style-span" style="font-family:arial;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2e-KxVJsK_PyZ9VhK69mEPptDzZlbnU1whHhHEYTXKM4Jy_Vc4UXkJIC8CQ6pRRdQMIHBkV_DGBQH_An6A8ROXoXj_McRcvdBXZhet82mgfZI76_n5oUaY2pEo9UY_qtvTvAgmeIJM2M/s400/Listener+Training+Tasks.png" border="0" width="400" height="335" /></span></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;">Figure 4: A list of the 17 different training tasks that focus on one or more of the four sound quality attributes: spectral (timbral), spatial, distortion and dynamics.</span></span></td></tr></tbody></table><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></span><span class="Apple-style-span" style="font-family:arial;"><br /><span style="font-size:100%;">To facilitate the training process, a proprietary computer-based software program called </span></span><span style="font-size:100%;"><b><i><span class="Apple-style-span" style="font-family:arial;">“How to Listen”</span></i></b></span><span class="Apple-style-span" style="font-family:arial;font-size:100%;"> was developed by Harman software engineers Sean Hess and Eric Hu. The software runs on both Mac and PC computers, and can play both stereo and multichannel music files. A real-time DSP engine built into the software application allows real-time manipulation of sound quality attributes in response to the listeners’ responses and performance.</span></div><div style="font: 12px Helvetica; margin: 0px; min-height: 14px; text-align: justify;"><span class="Apple-style-span" style="font-family:arial;font-size:100%;"><span style="letter-spacing: 0px;"></span></span></div><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">There are currently five different types of training tasks that focus on one or more sound quality attributes (see Figure 4):</span></span></div><ol style="list-style-type: decimal;"><li style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">Band Identification</span></span></li><li style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">Spectral Plot</span></span></li><li style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">Spatial Mapping</span></span></li><li style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">Attribute Test</span></span></li><li style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;font-size:100%;" ><span class="Apple-style-span" style="font-family:arial;">Preference Test</span></span></li></ol></span></div></div><div><span class="Apple-style-span" style="font-size:100%;"><span class="Apple-style-span" style="font-family:arial;">Band Identification (see Figure 5) teaches listeners to identify spectral distortions based on their frequency, level and Q-factor using combinations of peak/dip and highpass/lowpass filters. In each trial, the listener compares the unequalized version of the music track (FLAT) to a version that has been equalized (EQ) using one of the filters drawn on the screen. The listener must select the correct filter (Filter 1 or 2) they believe has been applied to the equalized version.</span></span></div></div><div><span class="Apple-style-span" style="font-family:arial;"><span style="letter-spacing: 0px;font-size:100%;" ></span><br /></span><span style="letter-spacing: 0px;"><div style="font: 12px Helvetica; margin: 0px; text-align: justify;"><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></span><span class="Apple-style-span" style="font-family:arial;"><br /></span><br /><table class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;" align="center" cellpadding="0" cellspacing="0"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7XVWHH-7Ld_3Zh7sM0A14jz0p3YOMr7OMBtgPPsARDer5xNG7eEyWq2MY1B4aRZw-MFyE3GjO73c2RsFfs1Em3vdnEt9Dqb_N_M-ogcnYQMBRLdd2t4RPmYanQoSbDut_jB8eHIHe7iM/s1600/BandID+With+Harman+Skin.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span class="Apple-style-span" style="font-family:arial;"><img src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7XVWHH-7Ld_3Zh7sM0A14jz0p3YOMr7OMBtgPPsARDer5xNG7eEyWq2MY1B4aRZw-MFyE3GjO73c2RsFfs1Em3vdnEt9Dqb_N_M-ogcnYQMBRLdd2t4RPmYanQoSbDut_jB8eHIHe7iM/s400/BandID+With+Harman+Skin.png" border="0" width="400" height="246" /></span></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span class="Apple-style-span" style="font-size:small;"><span class="Apple-style-span" style="font-family:arial;">Figure 5: A screen capture of the listener training task “Band Identification” in Harman’s “How to Listen” training software. The listener compares the unequalized music “Flat” to an equalized version (EQ) and must select the EQ filter that is associated with its sound.</span></span></td></tr></tbody></table><span style="letter-spacing: 0px;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></span></div><div style="font: 12px Helvetica; margin: 0px; min-height: 14px; text-align: justify;"><span class="Apple-style-span" style="font-family:arial;"><br /></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px; text-align: justify;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" >The difficulty of each training task automatically increases or decreases based on the listener’s performance. The listener is give immediate feedback on their responses, and they can audition all possible response choices when they enter an incorrect response. </span></div><div><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;"><br /></span></span></div><div><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span class="Apple-style-span">The training task </span></span><span style="font-size:small;"><b><i><span class="Apple-style-span" style="font-family:arial;"><span class="Apple-style-span">Spectral Plot</span></span></i></b></span><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span class="Apple-style-span"> requires the listener to compare different music programs that have been equalized a number of different ways. The listener must select the equalization curve that best matches its sound quality. This task teaches listeners to behave like human spectrum analyzers. Once fully trained, the listener can draw a graph of the audio system’s frequency response based on how it sounds.</span></span><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><br /></span><span style="letter-spacing: 0px;"><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; text-align: justify;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">The </span><b><i><span class="Apple-style-span" style="font-family:arial;">Spatial Mapping</span></i></b><span class="Apple-style-span" style="font-family:arial;"> task requires the listener to graphically indicate on a two-dimensional map where a sound appears in the listening space. The </span><b><i><span class="Apple-style-span" style="font-family:arial;">Attribute</span></i></b><span class="Apple-style-span" style="font-family:arial;"> training task requires the listener to correctly rank order two or more sounds on a given attribute scale based on the intensity of the attribute (e.g. bright-dull). For the </span><b><i><span class="Apple-style-span" style="font-family:arial;">Preference</span></i></b><span class="Apple-style-span" style="font-family:arial;"> task, the listener must give preference ratings where the sound quality of the music has been modified for one or more sound quality attributes. The performance of the listener is calculated based on a statistical post-hoc test that determines the discrimination and reliably of the listeners’ preference ratings. Together, these different training tasks teach listeners to critically evaluate any type of sound quality variation they are likely to encounter when listening to recorded and reproduced sound.<br /><br /></span></span></div><div style="font: 12px Helvetica; margin: 0px;"><span style="letter-spacing: 0px;font-size:130%;" ><b><span class="Apple-style-span"><span class="Apple-style-span" style="font-family:arial;">Conclusions</span></span></b></span></div></span><span style="letter-spacing: 0px;"><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px;font-family:Helvetica;"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">The evaluation of sound quality remains an elusive art in the audio industry. Better awareness, understanding, and appreciation of sound quality may be possible if there existed a method to teach listeners how to evaluate the quality of reproduced sound and report what they hear using well-defined and meaningful terminology. </span><b><i><span class="Apple-style-span" style="font-family:arial;">How to Listen</span></i></b><span class="Apple-style-span" style="font-family:arial;"> is a listener training course that aims to achieve those goals. Listeners are taught to identify and rate audible changes to different sound quality percepts related to the spectral, spatial, dynamic and distortion qualities of recorded music. Performance metrics based on the discrimination, accuracy and reliably of the listeners’ responses are factored into whether the listener meets the criterion of being a “trained” listener. The question of whether a listener is truly golden eared or not, is no longer a matter of conjecture and debate since <b>How to Listen</b> will ultimately reveal the true answer.</span></span></div></span><span style="letter-spacing: 0px;"><div style="font: 12px Helvetica; margin: 0px; min-height: 14px;"><span class="Apple-style-span" style="font-family:arial;"><span style="letter-spacing: 0px;"></span></span></div><div style="font: 12px Helvetica; margin: 0px; min-height: 14px;"><span class="Apple-style-span" style="font-family:arial;"><span style="letter-spacing: 0px;"></span></span></div><div style="font: 12px Helvetica; margin: 0px; min-height: 14px;"><span style="font-size:100%;"><b><span class="Apple-style-span"><span class="Apple-style-span" style="font-family:arial;">References</span></span></b></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px;font-family:'Helvetica Neue';"><span style="letter-spacing: 0px;font-size:small;" ><span class="Apple-style-span" style="font-family:arial;">[1] Sean E. Olive, "Differences in Performance and Preference of Trained Versus Untrained Listeners in Loudspeaker Tests: A Case Study," J. AES, Vol. 51, issue 9, pp. 806-825, September 2003. Download for free </span><span style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; text-decoration: underline;font-family:'Helvetica Neue';" ><a href="http://www.aes.org/e-lib/download.cfm?ID=12206&name=harman"><span class="Apple-style-span" style="font-family:arial;">here</span></a><span class="Apple-style-span" style="font-family:arial;">,</span></span><span class="Apple-style-span" style="font-family:arial;"> courtesy of Harman International.</span></span></div><div style="font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px; min-height: 14px;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" ><span style="letter-spacing: 0px;"></span></span></div><div style="color: rgb(30, 0, 175); font-size-adjust: none; font-stretch: normal; font-style: normal; font-variant: normal; font-weight: normal; line-height: normal; margin: 0px;font-family:Helvetica;"><span class="Apple-style-span" style=";font-family:arial;font-size:small;" >[</span><span class="Apple-style-span" style=";font-size:small;color:black;" ><span class="Apple-style-span" style="font-family:arial;">2] Sean E. Olive, “</span></span><span style="font-size:small;"><a href="http://seanolive.blogspot.com/2010/07/are-there-cross-cultural-preferences-in.html"><span style="letter-spacing: 0px; text-decoration: underline;"><span class="Apple-style-span" style="color:black;"><span class="Apple-style-span" style="font-family:arial;">Are There Cross-Cultural Preferences in the Quality of Reproduced Sound?</span></span></span></a></span><span class="Apple-style-span" style=";font-size:small;color:black;" ><span class="Apple-style-span" style="font-family:arial;">” Audio Musings, July 2, 2010.</span></span><span style="font-size:small;"><a href="http://www.aes.org/e-lib/download.cfm?ID=12206&name=harman"><span class="Apple-style-span" style="color:black;"><span class="Apple-style-span" style="font-family:arial;">here.</span></span></a></span></div></span></div></span></div></span></div>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com33Oak Park, CA, USA34.1716667 -118.757777834.153913700000004 -118.7869603 34.1894197 -118.7285953tag:blogger.com,1999:blog-7172143857693272648.post-21260685363473687142010-09-18T15:42:00.000-07:002010-09-18T16:11:01.372-07:00Harman Debunks Youthful Music Myths<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGt8QSRbXN80EO1Z2UG58s9ucNvko-cLL32dzeNf3Ob7NA-uxdjcvF964pVBDpHZg-ZjqH7vFZ9aZN1SrRqhC889TAalqVOBsWV515Zd7EqMP2da-HktyaY_XxG0UH6WgCiSnG3bt6LW8/s1600/death+of+sound+Quality.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGt8QSRbXN80EO1Z2UG58s9ucNvko-cLL32dzeNf3Ob7NA-uxdjcvF964pVBDpHZg-ZjqH7vFZ9aZN1SrRqhC889TAalqVOBsWV515Zd7EqMP2da-HktyaY_XxG0UH6WgCiSnG3bt6LW8/s400/death+of+sound+Quality.png" width="400" /></a></div>Robert Archer, a writer at <a href="http://www.cepro.com/">CEPro magazine</a> has written a nice article called "<a href="http://www.cepro.com/article/harman_debunks_youthful_music_myths/K536">Harman Debunks Youthful Music Myths</a>." The article is based on an interview he did with me a couple of weeks ago, and summarizes some recent Harman research on Generation Y's sound quality preferences for different digital music file formats (MP3 versus CD) and loudspeakers. The details of the preliminary research were first reported back in June in a blog posting, "<a href="http://seanolive.blogspot.com/2010/06/some-new-evidence-that-generation-y.html">Some New Evidence that Generation Y May Prefer Accurate Sound Reproduction</a>."<div><br /></div><div>The early results of that research suggest that today's youth prefer higher quality music formats and accurate loudspeakers <b><i>when</i> </b>given the opportunity to A/B them under controlled, double-blind listening conditions. While it is refreshing news that good sound is not lost on today's youth, the challenge is to figure out how to market and sell it to them. </div><div><br /></div><div>Unfortunately, good A/B audio demonstrations are becoming nearly extinct. Internet and Big Box store sales of audio equipment and music generally don't provide such listening opportunities. In the end, consumer education, meaningful audio specifications and measurements that are indicative of a product's true sound quality, and accurate, unbiased product reviews, will help consumers make more informed audio and music purchase decisions as they relate to sound quality. Until then, most consumers will never know for sure whether or not they've purchased something that is truly "good enough."</div><div><div><br /></div></div>Dr. Sean Olivehttp://www.blogger.com/profile/17909033506833141612noreply@blogger.com1