Audyssey Labs' MultEQ - page 3
The Listening Environment
USC's Immersive Audio Lab appeared larger than an IEC-standard 3000 cubic foot listening room. I would guess the dimensions at ~15' W X ~20' L X ~ 12' H. or approximately 3600 cubic feet. Since the Denon AVR-5805 is THX Ultra 2 certified for our test purposes there should have been sufficient power to take the prospect of amplifier distortion on peaks out of the listening equation.
There were two complete 5.1 systems in the room. The powered, 12" three-way amplified Genelecs that Tom always uses for a reference and a second, much lower priced Klipsch system which would be used for the day's demonstration.
In case you're wondering, the Genelec systems used for "dipole" side-mounted surrounds consisted of two 12" three-way systems stacked, one on top of the other, but with one system facing toward the front of the room and the second system facing toward the rear. These two giant "dipoles" were mounted about 8' high on custom-made steel four-poster stands and positioned at about 80 degrees from the front wall's center, just in front of our listening position.
The Klipsch's were a ~$2500 system featuring double 5.25" mid-woofers in the two-way center channel speaker. Klipsch's ubiquitous Tractrix horn tweeter was between the two mid-woofers. This speaker was mounted horizontally on a 48" stand in front of us so that it could fire just over the A/V mixing console that dominated the center of the room in front of the listening position. The left and right speakers appeared to be the same models as the center except that they were mounted vertically on somewhat shorter stands. The surrounds were 5.25" two-way dipole designs with an approximate 90 degree included angle on their opposing faces. They too were mounted on stands. We three were standing a bit back from the console, almost on a plane with the rear speakers when listening.
It appeared that the room had been carefully treated with a mix of moveable and fixed absorptive and diffusive panels on the room's sides and back wall. On the front wall, in addition to an ~80" projection screen there were a couple of absorptive panels along with just a couple of foam, 7th order quadratic diffuser panels. The ceiling was a drop ceiling which, if not properly weighted from above can act as a bass vent as SPLs rise. One of the Audyssey technology papers which Chris and his partners have presented in the last couple of years describe a test room with a virtually perfect RT60 = 0.3 seconds. I figured this was the room.
The first-article Denon AVR-5805 that was to be used for the demonstration was laid ignominiously upside-down on its top so that access to the TI chipset containing the MultEQ 512-tap per channel algorithms could be accessed. The Denon's cooling fans were running full time as a result of having their intended (top) air box outlets blocked by being put in such an unorthodox position. But even full-on, the sound of the fans was noticeable only with no program material playing and having an ear within 2 feet of the unit.
I had been intending to rent the "Standing in the Shadows of Motown" DVD-Video for quite a while, but hadn't. So unfortunately, I thought, I would be going into yet another of the hundreds of audio demos I had heard over the years, without a good point of reference, such as how this acclaimed documentary might sound on my home system.
Chris cued up track 1, the live concert segment featuring Joan Osborn's rendition of "(Love is Like a) Heat Wave". Further thoughts of any reason for an A-B with my well set-up home system vanished. After thirty years in this business; as a Product Manager, as a speaker designer; even as a trained listener in Harman's well-regarded (and very neutral) Multi-channel Listening Lab, I have never heard such a monumental improvement in the sound of an audio system as I heard with the Denon AVR-5805 with MultEQ engaged.
Conversely, the sound of the Klipsch left/center/right trio without MultEQ engaged was distinctly Klipsch and resided in each of the three front speakers at their 4' height level. Joan's voice came from the center channel and the sounds of the band and crowd could be heard neatly separated to their appropriate left and right positions. In the rear, the crowd sounds could be distinctly heard to our left and right with a gap in the crowd sound between the left side surround and left front speaker and with a similar gap between the right side surround and right front speaker.
With MultEQ engaged once again the entire surround sound stage defined by the crowd wrapped completely around us in a 360 degree circumference as if we were situated at the camera angle as seen on the screen, about 30 feet back in the audience from the stage. In addition, the crowd sound had both depth and height, adding to the 3 dimensional effect. The crowd clapping was distinct and individually delineated for audience members who had been close to the surround microphones. Up front, Joan's voice and the sound of the band were up at exactly their height and spread precisely across the stage as depicted on the screen. (This was three feet above the actual height of the speakers!)
MultEQ Engaged MultEQ Off
You could hear that the recording engineer accurately tracked and mixed both the vocals and the band's instruments so that the band's stage reinforcement sound system, as heard at that distance, was probably exactly what the crowd had heard.
The drums and bass guitar were completely distinct from each other, with defined slam at all frequencies, and tuneful as all get out. (Did I mention that this perfect splicing of the satellite center channel to the LFE channel was done with a single subwoofer?)
What was heard was the sound of a great band backing up Joan Osborne who herself was belting out the Martha and the Vandellas hit for all she was worth. The room's walls had disappeared. I mean, I could still see that the walls were there but the immersion experience was so deep that it seemed like the sound actually expanded, in a completely natural manner, beyond the wall's boundaries.
The speakers and any sonic character I might have attributed to that particular brand from previous listenings became irrelevant. This was the most realistic, electronically reproduced presentation I've ever heard. It seemed apparent that the Denon/Audyssey system was pulling off the recorded information in a manner which had been heard by the recording engineer at the time of the event. The only spoilers to the illusion were the two dimensionality of the video itself and that the lights were on in the room.
One of the lessons I've learned over the years is that if you're aware that you're listening to something, whether it be the speaker, the amplifier or a new set of cables, then, by definition, you're listening to a distorted reproduction generated by some component within your system that is itself flawed. Reproduction at home has almost always been so. For it is our listening environment which speaks to us just as loudly as the reproduction we hear from even our finest CDs and DVDs when played back within that room.
No electronic system is capable of changing the actual reverberation characteristic of a room by absorbing the acoustic energy of reflecting sound waves. Rather, the energy is manipulated, with appropriate attention and understanding given to the psychoacoustic importance of each and all frequency bands as related to the room/loudspeaker system characteristics at the listening position(s).
Having said that, the Audyssey MultEQ algorithms appear to offer the most accurate solutions to resolution of absolute phase, seamless splicing of subwoofer-satellites, and "every seat is a good seat" to date. The technology fits neatly within the Texas Instrument's Performance Audio Framework DSP package and is apparently very scaleable and therefore memory-efficient. Yes, the Audyssey technologies, promising as they are, must still prove themselves in the consumer arena where perfectly treated rooms do not exist. But having seen and heard this first, brilliant execution of MultEQ, I have no doubt that Audyssey Labs is up to the challenge.
Audyssey's Founding Team consists of:
co-founder and CTO
co-founder and Chief Scientist
Sunil Bharitkar, PhD
co-founder and VP Research
co-founder and VP Engineering
For more information visit Audyssey