It seems that the difference between the Trinnov solution in the 997 and an Audyssey solution in some other processors would be Trinnov's ability to reposition versus the possible Dynamic EQ feature. So far, I'm led to believe that in my case Dynamic EQ would be of more value to me.

For starters, I don't really understand how Trinnov can reposition sound localization vertically. That implies to me attempting to create a frequency through adjustments to phase or amplitude at different frequencies, such that drivers located at the desired vertical position end up creating the desired frequency. But I imagine that might be attempting to use those drivers at their unintended frequencies. And something only possible at a sweet spot.

I am relatively satisfied with my current speaker placement, and do not need any horizontal adjustment. I could benefit from vertical adjustment but not sure how well that can work.

In comparison, I can see immediate benefits from Dynamic EQ during movies or music with large dynamic range. I imagine the result of using Dynamic EQ would be more significant than repositioning.

I did some more reading about Dynamic EQ over on AVS Forum. Subjective observations seem to describe it has adjusting for perceived frequency response rather than for room anomalies at different volumes. If that's the case, I wouldn't use it.

That makes no sense. The room's frequency response doesn't change based on volume level, the way our human hearing does, so it would be pointless to make that sort of correction.

I can only think of one way for a room's contribution to frequency response to be a function of volume: absorption.

If my sound treatments completely absorb 200Hz @ 85dB, but not so 200Hz @ 100dB, then you could compensate for the additional reflective gain when at 100dB. Your cut filter would only be active then.

But it seems what people are describing on AVS Forum is that because our hearing is less sensitive at high frequencies, and likewise people like feeling bass, then if you are listening at -30dB Audyssey Dynamic EQ will boost bass and high frequencies so you can still hear/feel them. Subjective observations.

If your sound treatments cause a dip at 200Hz, then they will continue to do so, by the same amount, irrespective of volume level. That's why there are no volume-based equal-loudness curves for rooms, just for our human hearing. There's more going on than that, and it has nothing to do with whether people like "feeling bass" or not. As the volume level is lowered, we hear low frequencies drop much faster than the rest of the frequency range. Same with high frequencies, though to a much lesser extent. Likewise, sounds around us will appear to drop in volume faster than sounds in front of us.

In order to compensate for this inconsistency in our hearing, specific amounts of boost have to be applied to the surround speakers, the bass and a bit of the treble. This has little to do with the fact that our hearing is "less sensitive at high frequencies" and more to do with how our hearing behaves when volume levels change. And because this inconsistency changes based on volume level, the correction has to be dynamic as well (i.e., different correction curves have to be applied, depending on how far away the level is from calibrated reference). Hardly. It's measured phenomenon, with correction curves calculated as early as 1933.

Yes, the initial dip at 200Hz would be the same at all volume levels, but the existence or non-existence of reflections resulting in gain would not be the same, yeah?

I understand the psychoacoustics and that it's a measured fact. I was referring to the comments on AVS Forum being subjective observations rather than objective measurements.

Regardless, I listen to movies at reference level when the sound matters, which is why Dynamic EQ doesn't seem to be for me.

The reflection would remain proportionate to the direct sound, irrespective of volume level. That's why room correction systems set one-time filters rather than changing the correction dynamically. There's no need to do the latter. If you listen to everything at reference level, then you have no use for equal-loudness technologies. However, that's different from your original reason for not using it because it doesn't adjust for "room anomalies at different volumes". There's no room correction system that does that, nor are you likely to see one in the future that does.

Heh, the only time I play movies at reference level is when I'm demoing my system.

Reference level is really loud. I'd be worried about hearing loss from playing movies that loud all the time.

-15db of reference is about the loudest I go normally.

Yeah, I only listen at reference levels when I'm playing back something that really wants it. A lot of the time I'm watching other DVDs where it doesn't really matter. I try to keep my hearing in good condition.

Ive written some programs to test equal loudness... it is very real and also very variant depending on the person. It should help everyone hear things more like they are reference, but would be cool to have a customized user test. Everyone's equal loudness curve is different... but everyone's hearing and opinion of 'good' is different to. At some point you just have to give up that your hearing response is different from everyone that made the movie/cd/game.