Harman Debunks Youthful Music Myths

Robert Archer, a writer at CEPro magazine has written a nice article called "Harman Debunks Youthful Music Myths." 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, "Some New Evidence that Generation Y May Prefer Accurate Sound Reproduction."

The early results of that research suggest that today's youth prefer higher quality music formats and accurate loudspeakers when 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.

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."

The Danger From Headphones

Below is an English translation of a recent article "Gefahr aus dem Kopfhörer" (The Danger From Headphones) written by Matthias Hohensee over at Valley Talk. His article refers to my recent investigations into whether younger generations prefer lossy MP over higher quality music file formats. The preliminary results of that study were reported in the article I recently posted called, “Some New Evidence that Generation Y May Prefer Accurate Sound Reproduction”.

Matthias makes a good point about listener preference for MP3 becoming a moot issue with higher quality file formats becoming the standard, as bandwidth and music storage costs drop. I only briefly mentioned this in my slide presentation (see slide 7), but it deserves repeating. The days of low quality music downloads are numbered, I hope. Then, the main sound quality issue will become the recordings themselves, and the quality of the headphones and loudspeakers through which the recordings are heard. What are your thoughts on this matter?

The Danger from Headphones

by Matthias Hohensee

from Valley Talk 6.30.2010

Can the Germans be really proud of MP3 or has the digital stroke of genius desensitized the hearing of a complete generation?

When Angela Merkel recently visited the prestigious Stanford University in Silicon Valley and enumerated German technology services, she also mentioned the data compression method MP3. The technology that was largely developed by scientists at the Fraunhofer Institute has changed the music industry, even though it’s mainly U.S. companies that profit from the MP3 player market.

But can the Germans be really proud of MP3? Or has the digital stroke of genius desensitized the hearing of a complete generation? At least the observations of Jonathan Berger suggest this. Over the years the Stanford professor of music has been asking his students if they are satisfied with compressed music files, or if they prefer the full Hi-Fi sound.

He came to a surprising result: For years, the number of those who preferred the sound of ‘packed’ music to the uncompressed audio spectrum seems to grow steadily. Berger concludes that the taste of sound has changed.

Good sound is measurable

Sean Olive, on the other hand, considers Berger's insight as nonsense: "Good, accurately reproduced sound is not a question of taste, but scientifically measurable." And this is the way he should see it. After all, Olive is the head of acoustic research at Harman International. The U.S. manufacturer is considered to be THE address for sophisticated sound systems.

Alarmed by Berger's observations Olive recently invited Los Angeles high school students to the Harman studios for extensive tests. "Everyone could hear the difference between different compacted sound files - and preferred less compressed songs," says the scientist relieved.

Danger from headphones

Now, Olive is not really unbiased, after all Harman sells nearly three billion dollars worth of high-end audio technology per year. But in fact, technical progress makes Olive's worries already obsolete. In times of high-speed Internet, data compression does not play the same role as it did in the nineties when the music piracy supplier Napster made MP3 popular.

The songs that were exchanged back then were extremely compressed in order to distribute them via the still slow Internet connections – but also to spare the limited memory of computers and MP3 players. Today the vendors such as Apple and Amazon are selling songs which are formatted in such a way that only real audiophiles can hear the difference to music CDs.

And so the real dangers for the hearing of ‘generation iPod’ aren’t the highly compressed music files, but simply the volume adjustment of their headphones.

Acknowledgements: Thank you to the author Matthias Hohensee for permission to repost his article here, and to Alena Winterhoff for the English translation.

Why Live-versus-Recorded Listening Tests Don't Work

Figure 1: Singer Frieda Hempel conducting a Tone Test at Edison Studios, NYC in 1918. Note that many of the listeners' ears are covered by the blind folds making it a double blind and double deaf listening test, since the experimenter Edison was deaf himself.

Recently I was asked how I could possibly prove or assert that listeners prefer accurate loudspeakers without having performed a live-versus-recorded listening test. This is a test where the listener compares a live musical performance to a recording of the performance reproduced through loudspeakers. The closer the sound quality of the reproduction is to that of the live performance, the more accurate the loudspeaker is deemed to be - at least in theory. In practice, these tests are usually ridden with so many uncontrolled listening test nuisance variables that the results are essentially meaningless. This article examines why live-versus-recorded listening tests are not suitable for serious scientific investigations of the perceived sound quality of recorded and reproduced sound.

Edison’s Tone Tests: “People will hear what you tell them to hear”
Thomas Edison was among the first audio engineers to embrace live-versus-recorded demonstrations. In 1910, he invented the Edison Diamond Disk Phonograph, which he claimed had “no tone” of its own. To prove it, a series of road shows involving 4,000 live-versus-recorded demonstrations of his phonograph were conducted in auditoriums across the United States At some point during the live music performance there would be a switch over to the recorded performance, and apparently audience members could not tell the difference between the live and recorded performances

After a 1916 live-versus-recorded demonstration in Carnegie Hall, the New York Evening Mail stated “the ear could not tell when it was listening to the phonograph alone, and when to actual voice and reproduction together. Only the eye could discover the truth by noting when the singer’s mouth was open or closed” [1].

By today’s standards, the fidelity of Edison’s disc phonograph was egregious in terms of its noise, distortion, limited dynamic range, bandwidth and frequency response (you can hear some of Edison’s recordings online here). It’s hard to imagine that listeners were fooled into thinking his Diamond Disk recording was indistinguishable from the live performance. In fact, we now know that Edison manipulated the tests to produce the results he wanted. First, he carefully chose the music and musicians to work within the technical limitations of his technology. Edison detested music with extreme dynamics, high tones, vibrato and complex textures because they were a challenge to his deafness and his Tone Tests. He selected and coached musicians to mimic the sound of their recordings to minimize the audible differences between live and recorded performances [1],[2].

Second, Edison was the consummate audio salesman and was known to say, “People will hear what you tell them to hear” [2]. The expectations and perceptions of his listeners were manipulated before the test to produce a more predicable outcome. Audience members were given a concert program before his Tone Tests that clearly told them exactly what they would hear, how amazing it will sound, and what an appropriate response would be:

“Those who hear this test will realize fully for the first time how literally true it is that Mr. Edison has made possible the re-creation of the artist’s voice. No more exacting test could be made to demonstrate that the New Edison actually does re-create the voice of the artist than to play it side by side with the artist who made the records. This is the final proof. Close your eyes. See if you can distinguish the voice of the New Edison from that of the artist. Did you ever believe it possible to re-create a voice? Note that the voice of the artist and the voice of the Edison are indistinguishable” [emphasis is mine] [ 3].

Figure 2: Another Edison Tone Test where extraneous biases related to sight and smell may have compromised the results based on the large number of listeners covering their noses. Perhaps a bad case of singer's halitosis made it possible to identify the live performance from the recorded one based on smell alone?

Other Live-Versus-Recorded Demonstrations

Following Edison’s live-versus-recorded demonstrations, other tests have been conducted by Harry Olson at RCA, and G.A. Briggs (Wharfedale) and Peter Walker at Quad in the 1950’s. [4]. A common problem with these demonstrations was double reverberation: the reverberation of the room was heard both in the recording, and again when it was reproduced through loudspeakers in the same room. This made it easier for listeners to tell the difference between the recorded and live performances.

Acoustic Research's Live-Versus-Recorded Demonstrations

During the 1960’s, Acoustic Research (AR), an American loudspeaker company, performed over 75 live-versus-recorded concerts in cities around the USA featuring The Fine Arts String Quartet, and the AR-3 loudspeaker [5],[6]. To solve the double reverberation problem, the recordings of the quartet were made in an anechoic chamber, or outdoors. Outdoor live-versus-recorded demonstrations had the added benefit that there were no room reflections in either the recording or the live performance. This made the demonstrations less sensitive to off-axis problems in the microphones and loudspeakers. It also relaxed the demands on the recording-reproduction to accurately capture and reproduce the complex spatial properties of a reverberant performing space.

The AR demonstrations apparently generated an enormous amount of free publicity in newspapers and audio magazines where it was reported that the reproduction of the recordings was virtually indistinguishable from the live performance. AR sales increased dramatically, to the point where in 1966 AR apparently owned 32% market share of loudspeakers sold in the United States.

A Live-Versus-Recorded Method For Testing Loudspeaker Accuracy

Edgar Villchur, head of Acoustic Research, to his credit, was a firm believer that loudspeakers should accurately reproduce the art (the recorded music) and not editorialize or enhance it. In a 1962 paper, he described a live-versus-recorded method for evaluating the accuracy of loudspeakers [7]. The method used a reference loudspeaker (the live performance) that was placed in the listening room with the loudspeaker-under-test. The goal of the loudspeaker-under-test was to accurately reproduce a previous recording of the reference loudspeaker playing white noise in an anechoic chamber. The original white noise signal was also fed to the reference loudspeaker during the listening test. The more similar the loudspeaker-under-test sounded to the reference speaker, the more accurate it was deemed to be, at least in theory.

Villchur acknowledged that the sensitivity and validity of the method depended on the quality of the reference loudspeaker, its directivity, and the choice of program material. White noise was more revealing of loudspeaker inaccuracies than music. His reference loudspeaker consisted of a single 2-inch midrange from an AR-3 loudspeaker selected because he found using multiple drivers caused acoustical inference that was audible in the anechoic chamber, but not so audible in a reverberant listening room; these differences would produce errors in the listening test. One wonders how a tiny 2-inch driver could have produced adequate high treble and low bass without distortion. These limitations would significantly limit the accuracy and usefulness of this listening test method.

Another problem with this method was that the anechoic loudspeaker recordings were made at a single point in space, and did not capture the directivity and off-axis characteristics of the reference loudspeaker. Unless the speaker-under-test had the same directivity and off-axis characteristics of the reference loudspeaker, it could never sound exactly the same in a reflective listening room. To compensate for these errors, Villchur used a trial-an-error process to find the best microphone position relative to the reference loudspeaker where the timbre of the anechoic recording best matched the timbre of the reference loudspeaker when placed in a room. Adjusting the recording to mimmic the sound of live performance was the reverse process of what Edison’s musicians did, but essentially it produced the same bias. (Edison would have been proud!)

Finally, it is not clear how Villchur controlled loudspeaker positional biases when comparing the reference loudspeaker to the loudspeaker-under-test. Loudspeaker positional biases have been shown to produce audible effects that are sometimes larger than the audible differences between different loudspeakers under test [9]. At Harman, these positional biases are eliminated via an automated speaker shuffler that places each loudspeaker in the same position of the room.

Summary of Problems with Live-versus-Recorded Tests

By today’s standards, the live-versus-recorded tests performed to date lack the necessary scientific controls and rigor to consider their results or conclusions accurate, repeatable and valid. Below are a few of the most significant psychological, physical, methodological or experimental listening variables that plague these types of tests. While it is possible to control some of these variables, others are either impossible, impractical or too expensive to control.

Sighted and Cross-Modality Biases

To date, most of the live-versus-sighted tests have been performed sighted, where non-auditory cues were available to allow the listener to identify whether they were hearing the live or reproduced sound source. These tests could have been easily made blind via an acoustically transparent curtain; however, scientific validity was apparently not the primary purpose of the test. The visual cues from the musicians (bowing, lip syncing) would also enhance the realism and presence of the reproduction, a well-known cognitive effect observed in research of binaural and virtual reality displays.

Listener Expectation, Authority Bias, Group Interaction Bias

In many of the public live-versus-recorded demonstrations, listeners expectations were manipulated by knowledge given to them by the organizers of the demonstrations. In some cases, listeners were told what the expected response should be before the test began (see Edison's concert programs above). In large groups settings, listeners' responses can be easily swayed by the opinions and reaction of other members in the group (a herd mentality), especially when an authority member is present. These biases are easily removed from live-versus-recorded tests by repeating the test for each individual listener. The live and recorded performances would have to be replicated for every listener, which makes the tests too difficult, expensive, time consuming, and impractical to use.

Qualifications of Listeners

None of the live-versus-recorded tests I've read about have reported the hearing and critical listening qualifications of the listeners who participated in them. These are important variables in the sensitivity and reliability of the test results, and can be easily quantified.

Live and Recorded Performances Must Be Identical

For live-versus-recorded tests to be valid, the live and recorded performance should be identical, having the same notes, intonation, tempo, dynamics, loudness, balance between instruments, and the same location and sense of space of the instruments. Otherwise, there are extraneous cues that allow listeners to readily identify the live and recorded performances. Midi-controlled instruments (e.g. player pianos) are but one example of how this problem could be resolved.

Positional Biases from Live and Reproduced Sound Sources

Unless the live and reproduced (e.g. loudspeakers) sound sources occupy the same physical locations, the listener can always identify the live versus recorded versions based on the localized positions of the sound sources.

Errors in the Recording

The usefulness of live-versus-recorded methods for perceptual measurements of sound quality in the playback chain is severely limited by errors in the recording. The recording errors are not easily separated from the errors in the playback chain (see circle-of-confusion). Microphones and microphone techniques both contain errors that limit the timbral, spatial and dynamic accuracy of the recordings through which we judge loudspeakers. Apparently the most effective live-versus-recorded demonstrations were conducted outdoors - effectively an anechoic environment - where the off-axis performances of the microphones and loudspeakers, and the complex spatial cues of a reflective room were largely removed as factors from the experiment. However, results from outdoor live-versus-recorded tests cannot be generalized to how the loudspeakers would perform in real rooms, where the off-axis sounds provide a significant contribution towards the listener's impression of the loudspeaker.

Lack of Proper Scientific Protocols, Listener Response Data, Statistical Analysis, Results

The most interesting characteristic of live-versus-recorded tests is that they never seem to provide listener response data, statistical analysis or published results. Eyewitness reports written in newspapers or magazines do not constitute scientific evidence.

Accuracy is Not Applicable to Most Recordings Made Today

Most recordings made today are not intended to sound like the live performance. Anyone who heard Taylor Swift's live performance with Stevie Nicks at the 2010 Grammy Awards understands why.(Note: you can relive the magical moment on Youtube. Warning: this may be offensive for the musically-inclined). About 90% of commercial recordings are studio creations consisting of a series of overdubs, processed with auto-tuning, equalization, dynamic compression, and reverb sampled from an alien nation. For these recordings, there is no equivalent live performance to which the recording/reproduction can be compared for accuracy. The only reference is what the artist heard over the loudspeakers in the recording control room. If the important performance aspects of the playback system through which the art (the music and recording) was created can be reproduced in the home, then the consumer will hear an accurate reproduction of the music, as the artist intended. It is possible to achieve this if we adopt a science in the service of art philosophy towards audio recording and reproduction.

Conclusions

In reviewing the history of live-versus-reproduced tests, most have been performed as elaborate sales and marketing demonstrations designed to fool listeners into believing that a product sounded much better and more accurate than it actually was. While live-versus-recorded tests have proven their merit as an effective marketing and sales tool, they have not yet proven themselves as a serious method for scientific experiments intended to advance our psychoacoustic understanding of music recording and reproduction.

The reason for this, I believe, is that live-versus-recorded tests do not adequately control important listening test nuisance variables, a prerequisite for accurate, reliable and scientifically valid results. It is not entirely coincidental, that (to my knowledge) none of the live-versus-recorded tests to date have produced a single scientific publication or new psychoacoustic knowledge.

Hopefully, you now understand why I don’t conduct live-versus-recorded loudspeaker listening tests.

References

[1] Harvith, J., and Harvith, S. Edison, Musicians and the Phonograph: A Century in Retrospect, Greenwood Press, N.Y (1987).

[2] Andre Milliard, “Edison’s Tone Tests and the Ideal of Perfect Sound Reproduction,” from Lost and Found Sounds’, NPR.

[3] Program for Edison Demonstration http://www.nipperhead.com/old/tonetest04.htm

[4] Wharfedale History: http://www.wharfedale.co.uk/About/History/tabid/66/Default.aspx

[5] Acoustic Research http://en.wikipedia.org/wiki/Acoustic_Research

[6] Edgar Villchur, http://edgarvillchur.com/

[7] Villchur, Edgar, “A Method of Testing Loudspeakers with Random Noise”, J. Audio Eng. Society, Vol. 10, Issue 4, pp, 306-309 (October 1962),

[8] Kissinger, John R.The Development of the Simulated Live-vs-Recorded Test into a Design Tool, presented at the 35th AES Convention, preprint 609, (October 1968

[9] Olive, Sean E.; Schuck, Peter L.; Sally, Sharon L.; Bonneville, Marc E. “The Effects of Loudspeaker Placement on Listeners' Preference Ratings”,JAES Volume 42 Issue 9 pp. 651-669; September 1994.

Harman Kardon's Quest to Standardize Sound

Above: Trained listener Alex Miller is evaluating the sound quality of three loudspeakers in Harman's Multichannel Listening Lab. The automated speaker shuffler ensures that each speaker is heard in the exact same position. The acoustically transparent, visually opaque scrim means the tests are double-blind and not influenced by brand, price or other sighted biases. The computer randomly selects the presentation order of the speakers in each trial and listener controls the switching so that experimenter bias is removed from the test.

There is a nice story written by Stuart Miles over at Pocket-Lint called "Harman Kardon's Quest to Standardize Sound". Check it out and leave a comment whether or not you think standards that define the sound quality of an audio product is something that would benefit the consumer.

This story came from a recent Harman Kardon press event held at Northridge where they kicked off Harman Kardon's Science of Sound campaign that aims to promote the science and philosophy behind how we develop and test our products.

A group of 18 European journalists attended the press event and received presentations from Dr. Floyd Toole and myself about how good sound is not a matter of personal taste, but rather something that can be quantified through scientific-based listening tests, measurements, and psychoacoustics.

The journalists experienced how we train listeners and then participated in brief double-blind listening tests of the Harman Kardon MS100 and MAS100 in our Reference Listening Room and the Multichannel Listening Lab (shown in the picture above).

Are There Cross-Cultural Preferences in The Quality of Reproduced Sound?

Do we need a new user menu where you dial in your nationality to match your taste in sound quality?

[click on image to see a larger version].

The field of audio is ripe with myths and unsubstantiated opinions. One of the most enduring opinions is that there are cross-cultural preferences in the sound quality of reproduced sound. Some of the more common cross-cultural assertions I hear repeated among audiophiles, audio reviewers and audio marketing executives include these:

1. Americans prefer more bass than Europeans and Japanese
2. Japanese prefer less bass and more midrange (and listen at lower volumes)
3. Germans prefer brighter sound
4. The British prefer “tighter” or more over-damped bass

To my knowledge, these statements are anecdotal, and have not been tested in any rigorous scientific way. Marketing has already given us misguided menus in media players and automotive head units that adjust the equalization based on music genre (e.g.jazz, classical, hip hop, rock, country music, Christian music, and heavy metal, etc). Do we really need another one based on where we were born? What could the “Canadian” sound have in common with a predisposition towards liking cold long winters, hockey, Molson beer, maple syrup, beaver tails, national health care, and the music of KD Lang and Celine Dion?

While it is easy to dismiss the importance of cross-cultural preferences, the subject is gaining serious attention from audio manufacturers expanding into new markets like China, India, Russia and South America. Now the same age-old questions are being asked: Are there cross-cultural preferences in the quality of reproduced sound or is good sound universal and transcend cultural differences?

---

Possible Reasons Why Cross-Cultural Preferences in Sound Quality May Exist

Very little research in cross-cultural sound quality preferences exists. Nonetheless, here are some proposed reasons why they may exist according to various sources.

Language, Dialect, Music

Certain spectral balances may compliment and enhance the timbre and intelligibility of different languages and dialects. Similarly the culture’s ethnic music and its instrumentation may be enhanced from certain loudspeakers or EQ. Wouldn’t this enhancement be added to the recording by the artist or the producer when it was mixed? If so, why do we need to duplicate in the playback chain? Is there such a thing as too much enhancement (think Dolly Parton)?

Influence of Regional Building Construction and Room Acoustics

One explanation for regional tastes for certain types of loudspeakers is related to the design and construction of the region's homes and apartments. This would affect the noise isolation and acoustical properties of the room, and its interaction with the loudspeaker. Massive, rigid plaster walls commonly found in older construction in Europe would provide more noise isolation and less absorption of bass than less massive and rigid walls used in typical American construction today. It is argued that a loudspeaker with less bass might sound better in the European room. It should be pointed out that if the different rooms and loudspeakers combine in ways that in the final analysis produce the same sound, this doesn't really constitute a difference in preferred sound quality. Different means are being used to achieve the same end goal. Fortunately, there are technological solutions for dealing with loudspeaker-room interactions at low frequencies so that decent bass performance can be achieved regardless of the room’s size, dimensions and stiffness of its walls.

Influence of Social Norms and Practices

Cultural practices and norms may influence how much bass people like, and how loud they listen to their music. For example, Japanese apartment dwellers may prefer to listen to reproduced sound at lower volumes to avoid disturbing their neighbors, which is a serious social infraction. On the other hand, American urban apartment dwellers may be more tolerant of bass and higher playback levels due to better noise isolation from the wall construction. Tolerance to your neighbor's subwoofers and loud music comes more easily if you know they own a handgun. The right to listen to loud music and bass in America is sort of protected under the second amendment (i.e. the right to bear arms). :)

---

Possible Reasons Why Cross-Cultural Preferences May Not Exist or Matter

The following arguments do not directly prove that cross-cultural sound quality preferences do not exist. They do provide evidence that the cultural entertainment, broadcast, recording and audio industries have largely decided to ignore cross-cultural preferences. Either they don't believe they exist, or if they do, catering to them doesn't make sense from a business or philosophical viewpoint.

Audio Manufacturers: One Product, One Sound

Most audio companies sell the same model of product in every country, only changing the language of the packaging/owners manual and the power supply voltage to meet the local requirements. Measurements of loudspeakers from different countries of origin tend to aim towards the same performance target. There is nothing in the objective measurements or the listening test results that indicate a unique sound, voicing or preference that can be attributed to the country of origin whether the loudspeaker is British, German, Canadian, American, French, Italian, Danish or Japanese [1]-[3]. Accurate sound seems to be the common universal attribute that matters most. These studies did not formally or systematically study the culture or race of the listener as a factor in loudspeaker preference, so the definitive study remains to be done.

Recording/Film Industries: One Product,One Sound

To my knowledge, record companies do not release different mixes of their recordings to satisfy different cultural tastes in sound quality. Fans of Lady Ga Ga apparently equally like (or dislike) her sound on the recordings whether they are in America, Europe or Asia. Similarly, there is no option in the iTunes store where you indicate your nationality or culture before downloading your music.

Universal Loudspeaker / Audio Standards in Broadcast

If you look at international audio standards for broadcasting (AES, IEC, ITU, EBU), and read the loudspeaker papers written by researchers within the BBC (British), CBC (Canadian) and NHK (Japanese), you will find a common set of performance criteria: flat on-axis response, extended bandwidth in bass and treble, smooth off-axis response and low distortion. At the broadcast level, the playback chain in different countries is not being influenced by cross-cultural preferences in the targeted audience where the content will be heard.

Concert Halls and Live Music Performance

Acoustical design of concert halls have generally followed well established standards and practices based on research using international listening panels. Qualities such as spatial envelopment, reverberation, clarity and richness of timbre are universally accepted as desirable qualities. The classical and romantic composers specifically wrote their music for these particular acoustics, and to radically alter the acoustics would not well serve the art.

The Global Economy

In the new global economy, the political, cultural, socioeconomic and technological barriers have been largely removed. As communication between different cultures improves, this will likely influence their attitudes, tastes and perception towards culture, music and sound reproduction. If there are cross-cultural differences in sound quality preferences, it seems likely that in the future these differences will converge, and taste in sound quality will become more homogeneous (hopefully, in a positive way).

Audio is science in the service of art

This philosophy assumes that music, its performance and recording are part of the art, and the goal of sound reproduction is to accurately reproduce the art. To serve the art, there is no room for cultural preferences or individual tastes in the design of the audio equipment used for reproduction of the art. It is presumed that any cultural sound quality preferences will be encoded in when the music when it is performed and recorded, and doesn’t need to be added again in the playback chain.

Here is a parallel analogy in painting: When a Monet art exhibit travels to different countries, the art is not altered, transformed or "improved" to suit the local tastes of the country. Art lovers want to see the original Monet, not a new and improved version with edge enhancements, higher contrast and 3D effects. The same is true of the sound of Vienna Philharmonic when they do a world tour. When they tour Japan, they don’t leave half the bass section at home because the Japanese do not supposedly like bass. So why would we want to tamper with the original sound of the Vienna Philharmonic when playing recordings of them through our audio system?

---

Research in Cross-Cultural Preference in Sound Quality of Recorded and Reproduced Sound

In the realm of perception there is an essential pan-human unity, and that most differences among cultures is only a “fine tuning” [4].

To date, very little cross-cultural research has been done in the perception of sound quality. One of the challenges in cross-cultural research is ensuring that the listener instructions, sound quality descriptors and semantic definitions of the scales have the same meaning across cultures. Fortunately, there are methods for removing language from the perceptual task. Multidimensional scaling allows listeners to judge different pairs of sounds based on their similarity. Then the perceptual attributes of the sounds (e.g. timbre or spatial related) can be identified through multivariate statistical methods like principal component analysis. In a study of different guitar timbres, Martens et al. found that native speakers of English, Japanese, Bengali, and Sinhala perceived the same underlying dimensions, but used different adjectives/semantics to describe the attribute [5].

In another study that compared Japanese and English speaking listeners’ perception of music recordings made with four different 5-channel microphone techniques, the authors found a common understanding of three critical dimensions in which the quality of the recordings differed [6].

Recently, we have begun testing cross-cultural sound quality preferences of music reproduced through different loudspeakers, equalizations, and automotive audio systems using American, Japanese and Chinese speaking listeners. While this work is still ongoing, the preliminary results do not show any evidence of cross-cultural preferences among the different groups. Accurate sound reproduction seems to be the common link across the preferences of the different cultures.

---

Conclusions

Very little research has been done in cross-cultural preferences in the sound quality of reproduced sound. What we know is that differe Preliminary investigations by the author in preferred spectral balance of music reproduced through loudspeakers have not revealed any significant differences in cross-cultural preferences to date. If cross-cultural preferences exist, the music and audio industries have largely ignored catering to them, instead distributing products that are optimized for a single universal audience.

Finally, an important question is whether audio companies should even be catering to these cross-cultural preferences if research eventually finds that they indeed exist? If the audio industry takes an “audio science in the service of art” philosophy where the goal is to faithfully and accurately reproduce the art as the artist intended, the question of cross-cultural preferences becomes moot. If certain cultures don’t like the sound of the art, then that becomes an issue between the artist and the recording producer/record executive - not the audio manufacturer.

For more discussion on this topic, please head over to WhatsBestForum.

---

References

[1] Floyd E. Toole, "Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 1" J. AES Vol. 23, issue 4, pp. 227-235, April 1986. (download for free courtesy of Harman International).

[2]Floyd E. Toole, "Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 2," J. AES, Vol. 34, Issue 5, pp. 323-248, May 1986. (download for free courtesy of Harman International).

[3] 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 courtesy of Harman International).

[4] John W. Berry, Ype H. Poortinga, Janak Pandey, Handbook of Cross-Cultural Psychology, Volume 1 Theory and Method, 2nd edition, Aug. 21, 1996.

[5] Martens, William L.; Giragama, Charith N. W.; Herath, Susantha; Wanasinghe, Dishna R.; Sabbir, Alam M.” Relating Multilingual Semantic Scales to a Common Timbre Space - Part II,” presented at the 115th Audio Engineering Convention, preprint 5895 (October 2003).

[6] William L. Martens, Sungyoung Kim, Atushi Marui,”Comparison of Japanese and English Language descriptions of piano performances using popular multichannel microphone arrays,” J Acoust Soc Am. 2008 May ;123 (5):3690

Science in the Service of Art

Last week, I've was given my own front page forum over at WhatsbestForum called "Science in the Service of Art", where I can write about any topic I wish. My first posting is called "Audio Science in the Service of Art".

I will probably post the same articles I write over there, on this blog as well. But for now, I recommend you go over there, read my article, and then leave your comments about what we need to do in order to improve the quality and consistency of recorded and reproduced music.

Harman is committed to a scientific approach towards the design and testing of audio products in the consumer, professional, and automotive audio spaces. Last week, Harman Kardon began a PR campaign called the "Science of Sound" where "Science in the Service of Art" is a major theme. You can read about this on the Harman Kardon web sites (click on the "about" link at the top of the page). Enjoy!

Some New Evidence That Generation Y May Prefer Accurate Sound Reproduction

Sound quality in mainstream music recording and reproduction is all but dead, at least according to the media reports published over the past year [1]-[6]. On the music production side, music quantity (as in volume and decibels) matters more than quality and dynamic range. Record executives and producers are forcing artists to squash the dynamics and life from their music in order to be the loudest record on the charts [5],[6]. Listening to one of these albums can induce an instant migraine, making you wonder if the record companies aren’t secretly owned by the makers of Excedrin (see slides 2-4 in this article’s accompanying PDF slide presentation or this YouTube Video ).

On the music reproduction side, convenience, portability and low cost are the purchase driving factors in this Mobile-Ipod Age of entertainment; sound quality need only be “good enough” [3]. The problem is that no one seems to be able to define what “good enough” sound quality means for Generation Y. Given that they represent the largest and youngest demographic in terms of music and audio equipment consumption, it's important to understand the attitudes and tastes of these twenty-somethings before it's too late. Getting these Millennials hooked on good sound now, means they're more likely to upgrade the audio systems in their future homes and automobiles acquired as they grow older and wealthier.

A common belief being spread by the media is that Generation Y is indifferent to sound quality, or worse, they prefer the tinny, sizzling sound of low-bit rate MP3 over higher quality lossless music formats (slide 4). This is based on an informal study conducted by a Stanford music professor, Jonathan Berger, who over a 7 year period found his students increasingly preferred music coded in lower quality lossy MP3 formats over higher quality lossless music formats [1]-[5]. “I think our human ears are fickle” says Berger. “What’s considered good or bad sound changes over time. Abnormality can become a feature” [1].

While Berger’s unpublished study raises more scientific questions than it provides answers, nonetheless it has been widely reported by the media, and has captured the attention of consumer and automotive audio marketing executives, who ultimately decide what level of sound quality is “good enough” for Generation Y (slides 4-7). There's an increased risk that sound quality may become the sacrificial lamb for products targeted at Millennials (they can’t tell the difference, after all) with the savings diverted to more salient “purchase drivers” such as industrial design, more features, advertising, and celebrity endorsements.

If someone doesn’t soon stand up for Generation Y and show some evidence that they care about sound quality, its death may become a self-fulfilling prophesy.

---

Some New Experiments on Generation Y Sound Quality Preferences For Music Reproduction

To this end, I recently conducted two listening experiments on a group of high school students (the younger half of Generation Y) to determine if their sound quality preferences in music reproduction were: a) consistent with those of older trained listeners used for product evaluation at Harman International, or alternatively b) indifferent or skewed towards preferring less accurate sound (slide 8).

Two research questions were asked in separate tests:

1. Do the students prefer the sound quality of lossy MP3 (128 kbps) music reproduction over the original lossless CD version?
2. Do the students prefer music reproduced through a more accurate loudspeaker given four different options that vary in accuracy and sound quality?

The students, who ranged in ages from 15 to 18 years, were visiting Harman on a class field trip (slide 9). A description of the listening tests and the results are summarized in the following sections.

---

Do High School Students Prefer Lossy MP3 Music Over Lossless CD-Quality Formats?

In the first double-blind listening experiment (slide 11), the students were presented two versions of the same program selection encoded in:

1. MP3 (Lame 3.97, version 2.3; constant bit rate @ 128 kbps). Note that this a 2 year old MP3 encoder that may be more representative of what Berger used in his study.
2. CD - The original lossless CD-quality version (16-bit, 44.1 kHz).

After hearing the same music several times in both MP3 and CD formats, the listeners indicated on a scoresheet which one they preferred: A or B. They were also asked to indicate the magnitude of preference (slight/moderate/strong), and provide comments describing the differences in sound quality they heard.

A total of 12 trials were completed in which preference choices were recorded using four different short program loops in three separate trials (slide 10). Three music programs and a recording of applause at a live concert were chosen based on their ability to provide audible differences between the lossy and lossless formats. The applause provided listeners a familiar acoustic signal that the author felt most listeners could easily judge based on its apparent naturalness.

The order of programs and MP3/CD formats was randomized by the listening test software to eliminate any order-related effects. Switching between A and B was performed by the test administrator via a custom Harman listening test software application. The listening test was conducted in the Harman International Reference Room, which provided a quiet, and controlled acoustic environment typical of a domestic listening room. Listening was done through a high quality, stereo playback system (JBL LSR 6336 with four JBL HB5000 subwoofers) calibrated at the listening locations. A comfortable playback level (on average 78 dB (B)) was used throughout the tests.

Two groups of nine listeners each participated in two separate listening sessions, which lasted about 30 minutes each.

---

Listening Test Results: Students Prefer Music in Lossless CD Versus MP3 Formats

When all 12 trials were tabulated across all listeners, the high school students preferred the lossless CD format over the MP3 version in 67% of the trials (slide 16). The CD format was preferred in 145 of 216 trials (p<0.001).

As expected, there were differences among individual students in their ability to formulate consistent preference choices (slide 17). Nearly 40% of the listeners gave a sufficient number of preference choices (9 of 12) to establish a statistically significant preference for CD (p <= 0.054). Only one of the 18 listeners preferred MP3 over CD (7 versus 5 trials), although the preference was not statistically significant ( p = 0.19). Other listeners were either guessing, and/or were inconsistent in their choices. With additional training and trials, the performance of these listeners would likely improve.

On average, the magnitude of preference for CD over MP3 was also stronger based on the frequency of responses assigned to the categories of preference: slight, moderate and strong preference (slide 18). When CD format was preferred, listeners assigned a proportionally higher number of moderate-to-strong responses compared to when MP3 was the preferred choice.

The preference for CD over MP3 formats was relatively independent of the program selection (slide 19). CD format was preferred for all four programs, with only a slight drop (68.5 % to 63%) for program JW.

Finally, the comments given by the more consistent listeners (slide 20) reveal the nature of audible differences between MP3 and CD. The CD version was often described as sounding more dynamic and brighter, with more impact on percussive sounds. MP3 versions of the programs were described as sounding duller, dynamically compressed with swirling-pitch modulation artifacts on vocal and strings.

---

Do High School Students Prefer Neutral/Accurate Loudspeakers?

Given that the high school students preferred the higher quality music format (CD over MP3), would their taste for accurate sound reproduction hold true when evaluating different loudspeakers? To test this question, the students participated in a double-blind loudspeaker test where they rated four different loudspeakers on an 11-point preference scale. The preference scale had semantic differentials at every second interval defined as: 1 (really dislike), 3 (dislike), 5 (neutral), 7 (like) and 9 (really like). The relative distances in ratings between pairs of loudspeakers indicated the magnitude of preference: ≥ 2 points represent a strong preference, 1 point a moderate preference and ≤ 0.5 point a slight preference.

The four loudspeakers were floor-standing the models (slide 22): Infinity Primus 362 ($500 a pair), Polk Rti10 ($800), Klipsch RF35 ($600), and Martin Logan Vista ($3800). Each loudspeaker was installed on the automated speaker shuffler in Harman International’s Multichannel Listening Lab, which positions each loudspeaker in same the location when the loudspeaker is active. In this way, the loudspeaker positional biases are removed from the test. Each loudspeaker was level-matched to within 0.1 dB at the primary listening location.

Listeners completed a series of four trials where they could compare each of the four loudspeakers reproducing a number of times before rating each loudspeaker on an 11-point preference scale. Two different music programs were used with two observations. At the beginning of each trial, the computer randomly assigned four letters (A,B,C,D) to the loudspeakers. This meant that the loudspeaker ratings in consecutive trials were more or less independent (slide 23).

---

Results: High School Students Prefer More Accurate, Neutral Loudspeakers

When averaged across all listeners and programs, there was moderate-strong preference for the Infinity Primus 362 loudspeaker over the other three choices (slide 25). In the results shown in the accompanying slide, as an industry courtesy, the brands of the competitors’ loudspeakers are simply identified as Loudspeakers B,C and D.

As a group, the listeners were not able to formulate preferences among the three lower rated loudspeakers B,C, and D, which were all imperfect in different ways. For an untrained listener, sorting out these different types of imperfections and assigning consistent ratings can be a difficult task without practice and training [5].

The individual listener preferences (slide 26) reveal that 13 of the 18 listeners (72%) preferred the Infinity loudspeaker based on their ratings averaged across all programs and trials.

When comparing the student's rank ordering of the loudspeakers to those of the trained Harman listeners (slide 27), we see good agreement between the two groups. The one exception is Loudspeaker C, which the trained listeners strongly disliked. The general agreement between trained and untrained listener loudspeaker preferences illustrated in this test is consistent with previous studies where a different set of listeners and loudspeakers were used [5],[6]. As found in the previous study, the trained listeners, on average, rated each loudspeaker about 1.5 preference rating lower than the untrained listeners, and the trained listeners were more discriminating and consistent in their ratings[5],[7].

The comprehensive set of anechoic measurements for each loudspeaker is compared to its preference rating (slide 28). There are clear visual correlations between the set of technical measurements and listeners’ loudspeaker preference ratings. The most preferred loudspeaker (Infinity Primus 362) had the flattest measured on-axis and listening window curves (top two curves), and the smoothest first reflection, sound power and first reflection/sound power directivity index curves (the third, fourth, fifth and sixth curves from the top). The other loudspeaker models tended to deviate from this ideal linear behavior, which resulted in lower preference ratings. Again, this relationship between loudspeaker preference and a linear frequency response is consistent with similar studies conducted by the author and Toole [9],[10].

Finally, sound quality doesn't necessarily cost more money to obtain as illustrated in these experiments. The most accurate and preferred loudspeaker - the Infinity Primus 362 - was also the least expensive loudspeaker in the group at $500 a pair. It doesn't cost any more money to make a loudspeaker sound good, as it costs to make it sound bad. In fact, the least accurate loudspeaker (Loudspeaker C) cost almost 8x more money ($3,800) than the most accurate and preferred model. Sound quality can be achieved by paying close attention to the variables that scientific research says matter, and then applying good engineering design to optimize those variables at every product price point.

---

Conclusions

A group of 18 high school students participated in two double-blind listening tests that measured their sound quality preferences for music reproduced in lossy (MP3 @ 128 kbps) and lossless (CD quality) formats, as well as music reproduced through loudspeakers that varied in accuracy. In both tests, the high school students preferred the most accurate option, preferring CD over MP3, and the most accurate loudspeaker over the less accurate options.

While this study is still in its early phase, these preliminary results suggest that these teenagers can reliably discriminate among different degradations in sound quality in music reproduction. When given the opportunity to hear and compare different qualities of sound reproduction, the high school students preferred the higher quality, more accurate reproduction over the lower quality choices.

The audio industry should not discount the potential opportunities to provide a higher quality audio experience to members of Generation Y. The popular belief that they don’t care about or appreciate sound quality needs to be critically reexamined. This data suggests there are opportunities to sell good sounding audio products to Generation Y as long as the products hit the right features and price points,. The audio industry should also provide these consumers the necessary education and information (i.e. meaningful performance specifications) to identify the good sounding products from the duds. Science can already do this (review slide 28), it’s simply a matter of making the information more widely available.

---

References

[1] Joseph Plambeck, “In Mobile Age, Sound Quality Steps Back,” New York Times, May 9, 2010.

[2] Andrew Edgecliffe-Johnson, “Could a Pair of Headphones Save the Music Business?” Financial Times, June 12 2010.

[3] Robert Capps, “The Good Enough Revolution: When Cheap and Simple Is Just Fine” Wired Magazine, August 24, 2009.

[4] Dale Dougherty, “The Sizzling Sound of Music,” O’Reilly Radar, March 1 2009.

[5] Nora Young, Full Interview: Jonathan Berger on mp3s and “Sizzle”, CBC Radio , March 24, 2009.

[6] The Loudness Wars: Why Music Sounds Worse, from All Things Considered, NPR Music, December 31, 2009.

[5] 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 courtesy of Harman International).

[6] Sean Olive, “Part 1 - Do Untrained Listeners Prefer the Same Loudspeakers as Untrained Listeners?” Audio Musings, December 26, 2008.

[7] Sean Olive, Part 2 - Differences in Performance of Trained Versus Untrained Listeners, Audio Musings, December 27, 2008.

[8] Sean Olive, “Part 3 - Relationship between Loudspeaker Measurements and Listener Preferences”, Audio Musings, December 28, 2008.

[9] Floyd E. Toole, "Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 1" J. AES Vol. 23, issue 4, pp. 227-235, April 1986. (download for free courtesy of Harman International).

[10] Floyd E. Toole, "Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 2," J. AES, Vol. 34, Issue 5, pp. 323-248, May 1986. (download for free courtesy of Harman International).