So, with this Audyssey Pro thingie, it's been mentioned that one can specify a target curve. Can one specify, say, "do not equalize" for frequencies above some chosen frequency (which would be an approximation to the Schroeder frequency)?
You can't specify the correction but rather the curve itself. So you are really setting overall tone of the system.
If not, what is the nature of the DSP at frequencies above Schroeder? Does it attempt to flatten the response including all reflections, or does it use windowing and then flatten the quasi-anechoic response? I'm very suspicious of any DSP that tries to EQ high frequencies without windowing.
It attempts to flatten the curve within +-3db. Alas, I find that it creates various problems of its own. While the overall curve might be flat, you get humps in mid-range which to me are objectionable. In Harman studies, they found this a major problem with expert listeners giving it poor scores. We currently have our Audyssey Pro disabled in our Wisdom system, getting ready to use JBL Synthesis SDEC-4500 with it which current works superbly well against its own brand of speakers.
How much does Audyssey Pro (say, for the 80.2) cost?
It costs a few thousand dollars. But I really cannot recommend it. I spent a month trying to tune it but it just doesn't perform. The best I can get it to do is with measuring one location. Multiple locations just creates a mess in my opinion. With single position, it improves bass performance some but degrades mid-range. Vocals just sound strange to me.
The problems I hear are also the same problems I heard when I tried to use the normal Audyssey on my Onkyo. There, I made one measurement and the results were complete degradation. I did another measurement in the same location and this time it provided an improvement.
Right now, the only system I can recommend is the above mentioned JBL SDEC-4500. I plan to write a tutorial on it soon. For now, the combination of that hardware and Harman Sound Field Management is to beat:
http://www.jblsynthesis.com/ProductDetails.aspx?prdid=29
You can see them above the bank of amplification in our rack, correcting 20 channels of audio: