Originally Posted by xnor
Disagree. The phantom center produced by a stereo setup definitely has its flaws. First, the room and the listeners distance to each speaker has to be absolutely symmetrical in order for dual mono to be perceived dead on center.
Secondly, comb filtering is a physical necessity with stereo. When both speakers play the same signal, the sound of the right speaker will arrive slightly delayed at the left ear and vice versa. This results in multiple frequency response dips (comb filtering). That's one reason why stereo sounds crap if there are no reflections from the room (they partly fill in the comb filtering gaps).
With a center channel you get a real center that is more stable, accurate and sounds better (flatter FR).
OK, maybe I should have said: "Under normal circumstances there should be very little perceivable difference when an image is positioned in the phantom centre", rather than there shouldn't "even be the slightest loss". I never stated there were no problems with stereo. Obviously there are flaws with stereo and in creating a phantom image, especially in a larger space and if not sitting in a line central to the speakers, as indeed I alluded to in my last post! However, I was addressing what bigshot stated and restated in his last post that without a centre channel he has "a huge gaping hole in the middle". While stereo does have it's imaging flaws, you should not have a huge gaping hole in the middle or anything even remotely similar to a huge gaping hole, so there is patently something seriously wrong with bigshot's system.
While 5.1 system does solve some the problems of the phantom centre in 2 channel stereo, it also introduces other stereo image problems because in the front you now have two smaller stereo soundfields instead of one large one, plus a stereo soundfield between the left and right rear speakers and other stereo images between each of the rear speakers and each of the front speakers. So, with the centre channel in 5.1 you solved one stereo problem but you've also introduced a whole bunch of new stereo imaging problems which, requires an even more precise listening position than stereo. The problem of a tiny "sweet spot" in 5.1 is reduced in cinemas by diffusing the soundfield using an array of (diffuser) speakers, which is why in a cinema you see 20 or more speakers all around the rear and side walls, rather than just two speakers in the rear left and right positions but of course that doesn't happen in a home 5.1 system. I'm surprised you didn't realise this or failed to consider it when you were disputing what I was saying about stereo in relation to 5.1!
Originally Posted by bigshot
Maybe it's magic. Come by and I'll play it for you and you can tell me why it sounds so good when it shouldn't!
I didn't say your room sounded good when it shouldn't, just apparently better to you relative to the obviously horrendous issues you've got with your front left and right speakers. In my opinion there is a massive gap between "better than horrendous" and "so good" but it's your room and you are obviously happy with it, so that's all that matters (to you).
BTW, you can use the old audiophile response when their beliefs are questioned, that science (acoustics in this case) doesn't know what it's talking about but you do and what's really happening must be some form of magic. That is if you don't mind sticking your head above the parapet and going against all the principles of acoustics which incidentally are employed in every concert hall, every cinema, every commercial recoding studio and every dubbing theatre. To be honest, your response is disappointing. From many of the other threads in which you have participated, I expected more from you than the old audiophile resort of "maybe it's magic". I also suggest your response would be more appropriate in one of the other, audiophile, forums than here in the sound science forum.
Edited by gregorio - 11/14/13 at 1:23pm