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Discussion Starter · #1 ·
I often/always read that the center channel of a home theater is the most important speaker to get. If my well-defined listening area is at the apex of an equilateral triangle and since I will always be sitting in the “sweet spot†between the two front channels, couldn’t a “phantom†center (center channel=none on my receiver) provide the same results? The only downside I see is when listening from other positions; the dialogue will be anchored only to the nearest speaker.
 

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You're articulating the exact reasons for having a center speaker-- the off-axis response. The center channel is important because with movie soundtracks, that's where the majority of the sound gets placed. For music, it's less important, and this is true even with multichannel music because a lot of those mixes either deemphasize or eliminate the center channel altogether.


However, the approach to a center speaker is almost always compromised. If the goal of having three speakers up front is to have a continuous seamless transition from left to right, then the best option is to have three identical speakers up front. But, with a home theatre, the TV sits exactly where that center speaker would ideally go, hence the horizontal center speaker. Because of the horizontal alignment, the center speaker will never perfectly match the mains. You can and should get the match as close as possible, but it will never be exact.


The real problem occurs when people try to mix and match center and main speakers. If the center speaker sounds different enough from the mains, it will disrupt the front soundstage and call attention to itself, even if it subjectively sounds better than the other speakers. In instances where you cannot sufficiently voice match with the mains, then the better option is to leave the center channel off altogether. IMO, you either need to do the center channel right, or don't do it at all.
 

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Discussion Starter · #3 ·
If I can paraphrase your response, " the off-axis response" would be the reason for a central; however, if I didn't move from my "sweet" spot, a center wouldn't be required. In other words, the requirement for a center is dictated by the size/location of the sitting area to the screen.
 

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Considering that a lot of people watch TV with friends and family, the off-axis response is a good reason. But, even if your watching is mostly in the center position, a center channel is still desirable because with 5.1 soundtracks it is a discrete channel. And IMO, if a soundtrack was recorded with a center channel in mind, then it should be played back in that configuration.


Unlike two-channel music mixes that are purposely mixed with a strong phantom center image, a 5.1 mix played back without the center speaker will often not have as stable a phantom image because it was not mixed with a four-channel configuration in mind. In this case, the center image is dictated by a preset mixdown formula to redistribute the center channel information between the left and right channels. Or depending on the receiver, some DSP processors might also create a stronger center image. But, in these cases, a well-matched center speaker will typically present a stronger center image, even if you're sitting in the sweet spot.


But, it's not desirable to use a center speaker just to use a center speaker. It should be matched. If not, then in a lot of cases the phantom center is preferable.
 

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Quote:
Originally posted by Woochifer
However, the approach to a center speaker is almost always compromised. If the goal of having three speakers up front is to have a continuous seamless transition from left to right, then the best option is to have three identical speakers up front. But, with a home theatre, the TV sits exactly where that center speaker would ideally go, hence the horizontal center speaker. Because of the horizontal alignment, the center speaker will never perfectly match the mains. You can and should get the match as close as possible, but it will never be exact.
That's what I always thought.


Right now I'm designing a 2.1 system - DIY sealed 18" subwoofer with sealed 3-way or 4-way main speakers (large woofer in it's own box under a good 3-way speaker w/8-10" woofer). Mains down to 20-25Hz, set the xover to 40-50Hz, total bass down to 16Hz (corner placed sub)... :)


This is a similar design - and 500 lbs. each, 16Hz - 35kHz -3db (+/- 1dB in midrange), $18,950/pair! http://www.vonschweikert.com/vrline/VR-6W.HTM
http://www.lalena.com/audio/faq/speaker/vr8.gif


A neat trick you can do with this design is implement "full range" center channel and surrounds for hi-rez 5.1/6.0 discs or 5.1 DD, DTS... The center channel 3-way speaker part might have to be "symmetrized", but would integrate just like the other channels.
 

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Discussion Starter · #6 ·
Came across the following AES Technical Document:


In a home music system setup it is preferable not to have a center speaker at all. To obtain the quality that high-resolution audio can provide, the left and right speakers will, of necessity, be relatively large. To also place a speaker of this size into the center will be unacceptable in the majority of domestic rooms. Furthermore, today's high quality two channel systems and recording techniques a very capable of creating solid center sound images. The home theater downwards compatible music surround sound system could thus have a 2/2 configuration and not use the center speaker.


Here's the entire ariticle:

http://www.linkwitzlab.com/hi-rez-cmt.htm


Good discussion.
 

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An aside: originally, home hi-fi was mono. When stereo was born, two satellites were added to the main full-size (center) speaker. Yes, stereo was originally 3-channel. The phantom-center phenomenon was discovered, and two full-sized speakers became the norm as the center speaker faded away.


The 'sweet spot' wasn't so important until the center speaker was eliminated. Theaters have always had a center channel, regardless of the rest of the syetem. I just thought some people were not aware of this, and shouldn't scoff at the thought of a center speaker, even with audio-only material.

Edit: I happen to agree that non-surround-encoded music sounds best in what my pre/pro calls 'front/rear stereo', which uses the mains and rears without the center. My center does sound as good as the rest, but the lack of separation is remarkable when I use a surround format with music.
 
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