Factors that Influence Listeners’ Preferred Bass and Treble Levels in Headphones

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 age, gender, culture, and other demographic category. 

But what about sound quality?  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? 

To answer this question, we recently conducted a  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.

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 AES e-library. A PDF copy of the presentation can be found here. Or you can view an animated version of the presentation on Youtube.

Harman Science of Sound Demonstrations at Rocky Mountain Audio Fest 2011

October 14-16, I will be  giving Science of Sound presentations for the Harman Luxury Audio Group (room #8020)   at the Rocky Mountain Audio Fest (RMAF) in Denver, CO. My demonstration will be repeated every 1/2 hour on the hour and half-hour.

Drop by and find out more about the science behind Harman audio product development and testing including JBL and Revel loudspeakers. I will be demonstrating our latest release of the "How to Listen"  software used for training and selecting listeners for product research and testing. Find out how discriminating and reliable you are as a critical listener.

Attendees will be given 30% discount coupons towards a copy of Floyd Toole's book "Sound Reproduction" (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.

I hope to see you there!

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).

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!