If you’ve been around the Home Theater scene for a while, you’ve no doubt run into the concept of equalization. Simply, and equalizer attempts to compensate for a frequency response problem by pre-filtering the audio with the inverse characteristic. If you have a 200Hz bass peak, an equalizer will create a complimentary dip to compensate for it, with the intended result being smooth, flat response.
Ah, if only we lived in an that ideal world. Or an anechoic chamber. But such is not the case. In reality, our home theaters or multi-purpose home entertainment rooms are far from perfect acoustic spaces. There is a different set of room-imposed flaws in each one of them, and within each room, a different set of flaws for each listening position, making even measuring such problems a very imprecise process. Usually, a technician will make a lot of response measurements over a large area and somehow average them together. That’s a great way to avoid “chasing” a nasty problem for one seat while ignoring a different problem in another…you just average them all out and apply whatever equalization more or less works for every seat. Or rather, doesn’t work for any seat.
What if we could custom equalize out response problems for each seat individually? What if we went even farther and worked not only on frequency response issues, but looked at time-domain problems too, like sound reflections from walls, or physical speaker misalignment? What if we did all of this by making a series of test measurements, then let some highly sophisticated math from another galaxy do the work, and create a custom digital filter for each speaker in the room that addresses problems caused by that room for each seat? Too cool, you say?
Yup, that’s for sure. That’s also, in simple terms, what the Audyssey process does. Audyssey MultEQ XT, MultEQ, 2EQ, and EQ all use variations on the process, to differing levels of sophistication. The most elaborate implementation is found in the Audyssey MultEQ XT system, which a custom installer makes use of a computer and software to make the necessary measurements and calculations to cover the most demanding installations. MultEQ XT can also be found in high-end receivers, and is the most powerful version yet released.
Below that, MultEQ, 2EQ and EQ vary in processing and measurement power, with the EQ version being a preset system tuned for HTiB systems and TV sound systems. And yes, the automotive sound industry may soon benefit from Audyssey processing too.
So you ask, “Who are these guys?” And well you should. From the Audyssey web site’s ‘about us’ page,: Audyssey Laboratories was conceived at the prestigious Immersive Audio Laboratory at the University of Southern California in Los Angeles, California. Dr. Sunil Bharitkar, Philip Hilmes, Prof. Tomlinson Holman, and Prof. Chris Kyriakakis were all involved in conceiving and creating the technology that was the basis for "spinning out" the company in July, 2002.
In late 1996, after a fierce competition among 117 universities, the National Science Foundation established a unique research center at USC that focused on immersive technologies. A key component of the Integrated Media Systems Center (IMSC) is the Immersive Audio Laboratory that was founded by Chris Kyriakakis and Tomlinson Holman. Over the past 10 years Tom and Chris have conducted research in audio signal processing, acoustics, and psychoacoustics. The results of their interdisciplinary research have been published in more than 100 technical journals and several books. One of the most challenging problems that they addressed was the comprehensive understanding of the negative effects of room acoustics on sound reproduction. It took 5 years of intense research and experimentation and more than $5M in research funds to fully understand and solve this intricate problem. No other facility in the world had the scientific expertise and the resources to fundamentally examine and solve this problem.
Sharp eyed readers may have picked up the name of Tomlinson Holman. Yes, the “T H” of “THX” fame, inventor of THX theater sound systems, home THX, and the founder of the entire THX program at Lucasfilm. That Tom Holman. For more about Tom, see the “THX” and “TMH” links at www.platinumhometheaters.com
We have been using Audyssey processing for over a year now with great results, and now recommend it to our clients, if built into receivers by Denon, Marantz, and Onkyo, or in high end component systems using the Audyssey Sound Equalizer product custom calibrated to the space.
For information on how you can get Audyssey MultEQ in your home theater, contact us at Platinum Home Theaters.
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