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Posted By: cvictorg Center channel speaker question - 10/20/10 01:30 AM
Came across this article and would like the opinion of the members here as to whether or not it is believable

http://theaudiocritic.com/plog/index.php?op=Default&blogId=1&&page=3

Center-Channel Speakers: What the Industry (Even the "White Hats") Often Refuses to Tell You

Looking at the market, I’ve found that nearly all center-channel speakers have a low, wide profile using an MTM—often called D’Appolito—array, with a pair of 4", 5.25", or 6" woofers flanking a dome tweeter. This style is decor-friendly, has a better partner acceptance quotient (PAQ?), and is physically well suited for perching atop a large-screen rear-projection display. While the driver layout of these speakers is sometimes called a D’Appolito array, few of them fit the criteria of the originator as to driver spacing, crossover frequency, and final response. These speakers, even the better ones, have a universal characteristic: strong, sometimes severe, lobing in the horizontal plane, which will be launched into the listening area either through reflected sound or direct radiation to off-axis listeners. Fig. 1 displays an example of a typical, currently sold, MTM center channel speaker. Lobing begins at 7.5 degrees and by 22.5 degrees is quite strong. This is a sweet-spot device!

I’ve had the opportunity to test hundreds of different loudspeaker systems over the past decade. From 80 to 100 Hz upward, the best systems—and I mean best in an absolute sense—have been 6.5" two-way designs. Two-way speakers by manufacturers such as Paradigm, PSB, Polk, NHT, JBL, Boston Acoustics, and Infinity make excellent center-channel choices, often at remarkably low cost. The optimal center-channel speaker choice will usually be a good-quality, vertically deployed 6.5" two-way speaker. Good sound, even greater value. Dedicated center-channel loudspeakers are designed and marketed as horizontally arrayed, low-profile, gracefully styled accessories for large-screen television. While the inclusion of a pair of woofers improves low-frequency capability, few of them will deliver an honest 40 Hz at the listening position and, frankly, there is no need for them to do so. They offer no other performance advantage, and most lack acceptable sound quality for more than one listener.

Question - Does it make more sense to use a 2-way speaker as a center channel speaker in the vertical position?
Posted By: JohnK Re: Center channel speaker question - 10/20/10 02:12 AM
Vic, yes I'm familiar with the excellent material in the archives of the Audio Critic and that specific article relating to center speakers. This is in agreement with other studies of the matter, which have shown vertical configurations to be superior to horizontal MTM speakers for the center channel.

This has also been my personal experience and I've frequently suggested here over the years that a vertical center as similar as possible to the mains should be used wherever feasible.
Posted By: cvictorg Re: Center channel speaker question - 10/20/10 02:41 AM
So - would 5 M3 v3 Bookshelf Speakers work nicely in a 1600 cubic foot room?
Posted By: bdpf Re: Center channel speaker question - 10/20/10 02:56 AM
I would still use the QS for surround.
Posted By: DreamTheater Re: Center channel speaker question - 10/20/10 03:02 AM
I have always heard it best to use a vertical floorstander at center, unfortunately most (including me) don't have the room to accomodate such a design, so we compensate with these horizontal space friendly arrays. Excellent article though, in my dream system I would have a projection screen and have it high enough off the ground that I could throw in a vertical center, and all 5 of my speakers would exactly match.
Posted By: JohnK Re: Center channel speaker question - 10/20/10 03:05 AM
Yes, 5 M3s would work nicely, but 3 M2s, a good sub and QS surrounds would work even better.
Posted By: cvictorg Re: Center channel speaker question - 10/20/10 03:32 AM
http://www.harman.com/EN-US/OurCompany/T...tions/13680.pdf

http://www.harman.com/EN-US/OurCompany/Technologyleadership/Documents/White%20Papers/multsubs.pdf

I've also been reading these papers on multiple subs - I was thinking about 5 M3s for the speakers and using 4 of these subs

http://www.lavasubs.com/12_inch/powered_home_subwoofer.html

one per speaker - just one more question - would it be necessary to put one under the "center channel" speaker as well?
Posted By: JohnK Re: Center channel speaker question - 10/20/10 03:48 AM
The Harman papers are well-known here and have been discussed fairly often. If you mean that you propose to put a sub under each speaker so as to create in effect full-range units, then sure, the center has to be included. Note, however, that this arrangement wouldn't achieve the benefits in room mode smoothing discussed in the Harman papers and Dr. Toole's book Sound Reproduction. That requires placing the subs at locations such as the midpoints of opposite walls or in diagonally opposite corners, not under the speakers.
Posted By: BlueJays1 Re: Center channel speaker question - 10/20/10 04:10 AM
Never heard of Lava subs before. The fact they market their subs by comparing them to Polk Audio models does not instill confidence. Don't get me wrong, Polk make some nice speakers and they have some models that offer excellent value but their subwoofers are rubbish.
Posted By: CatBrat Re: Center channel speaker question - 10/20/10 12:13 PM
Originally Posted By: DreamTheater
...in my dream system I would have a projection screen and have it high enough off the ground that I could throw in a vertical center...


I plan on using a 7 or 8 foot 2.35:1 AT (acoustically transparent) projector screen with 3 M80 in-cabinet's behind it. This would accomplish the same thing, no?
Posted By: cvictorg Re: Center channel speaker question - 10/20/10 02:49 PM
Check out this thread

http://www.avsforum.com/avs-vb/showthread.php?t=1275777
Posted By: jakewash Re: Center channel speaker question - 10/20/10 03:33 PM
Vertically oriented speakers are designed to have good of axis listening (horizontal dispersion), while horizontal speakers (most center channels) have good vertical dispersion and poor horizontal dispersion, which works well for mounting above or below sitting positions. I have done some non-scientific tests with my VP100/150 using only my SPL meter and my ears, the volume levels drop off by a db or 2 when you stand/sit outside of a narrow range outside of the horizontal center speaker. It doesn't sound odd or fuzzy just a lower volume.

Ideally your center would be the same as your mains, this is why Axiom now has the VP180 to better match the floorstanding speakers for those of us without the ability to use an M60/80 as a center.
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