Home Theater Forum - View Single Post - Audyssey MultEQ: Questions and Answers

audyssey · 05-03-2008, 01:36 PM

Highliner,

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1. Can you please confirm that, if I copy the Audyssey curve to the 'Manual' file in 3808, I would get exactly the same equalizer curve saved there and not some simplistic representation?

No, the copy to Manual does not preserve the same curve. Manual is not a mode supported by Audyssey. It is a very crude approximation of the many hundreds of MultEQ filter coefficients by 9 parametric bands. Also, all time domain correction benefits of the MultEQ FIR filters is lost by moving to Manual EQ.

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2. Also, as i mentioned before, in my case, the set up is made with only 2 front speakers hooked up (all times I tried 5.1 Audyssey auto set up, the 2 channel Stereo mode would not sound as nice, as auto set up run with only 2 front speakers initially hooked up and all other speakers unhooked; in 5.1 mode it does sound nice (perhaps the sub and the center/surround speakers compensate for the missing frequencies), but why would I listen to a music concert in 5.1? I mean, I see a concert scene in front of me and hearing some sounds from the surround speakers located behind me does not sound too natural, right?...).

That is very strange. The MultEQ filters are completely independent in each channel. Thus the front channels will have identical filters whether you run 2.0 (2.1) or 5.1 calibration. No sharing of signals across channels is performed by MultEQ as that would compromise imaging. Perhaps the perceived differences are due to different bass management settings in the two cases?

I also disagree with the notion that "a concert is in front so I should only listen from the front". In a real concert hall, a very large portion of the sound energy arriving at your ears is from reflections that occur from the side walls, the ceiling and other surfaces. These arrive within a few tens of milliseconds after the direct sound and have been found to greatly influence human perception of width and depth. After those first few milliseconds, sound is still bouncing around the room, but now the reflections become more random and are not identified with a specific direction. This is called the reverberant field and greatly contributes to the richness of sound. This is what distinguishes the best acoustic spaces from the bad ones. In psychoacoustic research it has been shown that we can not perceive reflections and reverberation if it is coming from the same direction as the direct sound. So, playing all that information from the front speakers only prevents you from enjoying the space in which the music was recorded.

Unfortunately, the reproduction of music over surround systems isn't always ideal. This is due to many reasons including the lack of understanding by some recording engineers of how to use microphones in the space and how to mix for multichannel. The film industry is decades ahead of the music industry in that respect. Many of the simulated surround modes suffer from the same issues. But there are great surround music recordings that can almost make you believe you are in the performance space.

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So, do you believe your advice to make more measurements still applies to the auto set up with only 2 front speakers?

Yes! More measurements will give the algorithm more information with which to work and you will notice differences, particularly in the low frequencies. Just don't measure too far away from the center position as I described in my previous post.

Chris

PS. I really appreciate your nice words about our work and our products