From the 1st ref:

Quote:
Judicious choice of room dimensions and listener location also helps to reduce front-back reversals.


I agree with Charlie: I have had a 6.1 system for almost 2 years now (1st with a DPL processor + 5.1, now with the 950), and I've never had a problem localizing sounds to the front or rear of the room. Maybe I am just lucky!

From the 2nd ref:

Quote:
Listeners cannot distinguish between sounds in front of the head and the "mirror image" position behind the head (i.e. +30º and +150º ) without additional information.


So now the plot thickens. NOT just along the center line (front to back). And notice the last phrase: "without additional information." I.e., with the visual cues from the display in terms of where the action is (or isn't), doesn't seem like to me it should be a problem. And ref 2 echos that:

Quote:
Many methods have been developed for reducing the frequency of these reversals, including ... visual stimuli ...


And ref 3 seals it:

Quote:
Non-individualized HRTF's were observed to cause a doubling of the frequency of front-back reversals over instances where the subject's own HRTF was used (which were double the frequency of free-field reversals) [Wightman & Kistler, 1989b; Wenzel, et al., 1991, 1993]. These data are of little importance to my experiments, as all stimuli were presented in front of the subjects. However, Wenzel, et al. also observed a sevenfold increase in the frequency of vertical confusions.[28] One would expect the perception of spatial patterns to be most adversely effected by this type of error.


So, vertical reversal is more common than front-to-back. Now if you read through the 3rd ref, he mentions he got an average vertical confusion rate of 34% compared to the average rate of 18% that Wenzel got.

So if vertical confusion happens 3.5x more often than fron-to-back, and the averages above are with vertical, that puts the average equivalent rates for front-to-back reversals at 9.7% and 5.1% respectively. Still, with no visual cues, only auditory. Ref 3 goes on to explain that:

Quote:
The main difference between their study and mine is that they used white noise. This strongly indicates that the stimulus I used is confusing. If it were not for the fact that I wished to compare my results to another study (Lakatos, 1993a) that used the 12-partial harmonic complex, then I would consider using another sound.


So, let me ask a question, and then conclude: Which would you rather use to compare real world performance of a speaker system *by ear*: test tones? Or you favorite CD or movie soundtrack?

With actual music or movie soundtracks, and with the visual cues obvious to the film format, and with *your own* head transfer function (not an average superimposed on the source signal) I still don't see where the problem comes in.

And I suppose it does make me a little sad that a THX Ultra2 setup didn't eliminate this for Sanjay. But then me myself and I: I'd still spread the rears 3 or 4 ft apart anyway. At least on the Anthem, you can specify in the config whether the 2 rears are side-by-side, or spread out.

Got to admit, I know more now than I did before!
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