Originally Posted by fitzcaraldo215
Jeff - now you are confusing all of us. I do not think I agree with your view. First, to my knowledge, there is no movie equalization rolloff, except in THX.
But, let's ignore program source material for the moment. Here is what I believe: to get accurate, perceptually "flat" reproduction in your room of the source material, and assuming a farfield setup, you need the standard target curve with HF rolloff. The Audyssey Flat curve is in fact flat in frequency response (except for MRC), but will sound perceptually brighter than the real thing, i.e., brighter than "flat" due to the effects of room reflections. Restated, the Flat curve does not sound perceptually flat except for near field listening.
I do not believe that Audyssey is in any way intended to be something that compensates or equalizes for program material, whereas something like THX does in fact do that. THX is a special case, attempting to solve a similar problem to Audyssey via HF rolloff. Hence, Audyssey must revert to Flat to get out of the way of THX, lest the HF rolloff be doubled.
Yes, you're right, that is confusing. So, Audyssey and THX are attempting to solve a similar problem with HF rolloff; is that "problem" not "movie equalization?" X-curve exists solely to achieve the sound of large movie venues on the mixing stage, and the Audyssey Curve is their way of bringing that sound to the home theater space.
Maybe this post from Chris K
will clear up the confusion?
"One of the key reasons for the roll off in the high frequencies is to compensate for the amount of direct vs reverberant sound energy in your room. Content is mixed in rooms in which the listener is dominated by direct sound. Most home listening rooms place the listener farther away and are more reverberant and so is dominated by reverberant sound. The high frequency roll off is a method to compensate for these differences. The rule of thumb is that the smaller the room the less roll off is needed. In your room it sounds like the standard Audyssey curve (called High Frequency Roll Off 1 in MultEQ Pro) is the one to start with. You can also try High Frequency Roll Off 2. The room volume is a rough indicator because other factors, such as absorption, also influence this decision."
Or maybe this other Chris K post
"It's not the soundtrack content that is equalized with a high frequency roll off. The dubbing stage where the content is mixed is calibrated to the X curve (with a roll off that starts at 2 kHz) so that it matches the sound system calibration in movie theaters. So the content on a DVD "assumes" that it will be played back on an X-curve calibrated system. The intent is to produce a "flat" perceived system response for the listeners.
But, although the content on the DVD is the same mix as that in the theater, the listening conditions are not. The reasons behind the x-curve are complex, but they have to do with the volume of the room, the reverberation time, and the listening distance (actually the critical distance that we talked about in the past). Because all of those factors are different at home, the content doesn't translate correctly and will sound too bright.So, the Audyssey reference curve was designed to make this translation and ensure that the content is perceived the same way it was in the x-curve calibrated stage.
If a typical home theater system is calibrated to flat it will be way too bright. There are exceptions: when there is a lot of absorption in the room, for example. But, in general, a roll off is required for proper translation to account for the differences I talked about above."Edited by pepar - 6/2/13 at 6:52am