A Better Center Channel?

[sdolezalek]

But the real kick is that there's a much simpler, predictable and better performing solution with a simple vertically aligned point source properly placed. Proper 'placement' is right in front of the display! Lol.....but seriously......the simple compromise is below or above the screen angled at the listeners. If the system has good off axis response, at a typical listening distance center channel info should cover the seated area better than other options as phantom centers and the things you and others have been experimenting with.

 

Mayhem: Thanks for the very helpful explanation. The only issue I have with it is that I have tried this by placing a single Magnepan 3 series right in the center between my 20.1's and it is far less satisfactory than the tri-center in its place. Both the 3 and my original just CCR center channel configuration gave a sense of voices coming from a hole or window in the center wall. The tri-center makes them seem much more holographic (and delay functions are then used to align that holograph with the plane of the right and left speakers). Might there be something to the combination of the Maggies' very wide but figure 8 dipole dispersion pattern as well as you previously commented, the radiating surface area, that changes the combing equation?

[Kal Rubinson]

Comb filtering as we're discussing it results in cancellations, the more intense the effect the more a perceived loss of high frequency content. It can exist in both the horizontal and the vertical so adjusting speaker positions in both planes can certainly help as you've experienced. Typical horizontally aligned center channels as Kal mentioned do seem to 'beam' high frequencies, but that's not what is really happening here. This may help....

....................................................................................

 

So hope this helps.

Yes, I was not talking about beaming but, as you further inform, about the orderly cancellation/reinforcement that causes changes in perceived tonality across the radiation plane. My take on the use of multiple, multidriver or panel speakers is that they can smear the spatial distribution of those changes due to the wider/indeterminate sources in the individual speakers, themselves, thereby making the changes less perceptible. Possible.

[mayhem13]

Yes, I was not talking about beaming but, as you further inform, about the orderly cancellation/reinforcement that causes changes in perceived tonality across the radiation plane. My take on the use of multiple, multidriver or panel speakers is that they can smear the spatial distribution of those changes due to the wider/indeterminate sources in the individual speakers, themselves, thereby making the changes less perceptible. Possible.

 

Agreed.

[mayhem13]

Mayhem: Thanks for the very helpful explanation. The only issue I have with it is that I have tried this by placing a single Magnepan 3 series right in the center between my 20.1's and it is far less satisfactory than the tri-center in its place. Both the 3 and my original just CCR center channel configuration gave a sense of voices coming from a hole or window in the center wall. The tri-center makes them seem much more holographic (and delay functions are then used to align that holograph with the plane of the right and left speakers). Might there be something to the combination of the Maggies' very wide but figure 8 dipole dispersion pattern as well as you previously commented, the radiating surface area, that changes the combing equation?

 

Are we talking about in the space that holds the single center above the display as in your photo?

[maelob]

Wow I have to say you guys are something! Lol love all your technical curiosity and know how. Just an idea, Why not trying the matching synchrony center channel to see how it sounds.

[Paul R]

Wow I have to say you guys are something! Lol love all your technical curiosity and know how. Just an idea, Why not trying the matching synchrony center channel to see how it sounds.

 

Yep- did just that, and while it sounded wonderful - it more or less still beamed and just never sounded as good as a phantom center channel from the Synch 1Bs. The pair of Imagine Bs sounds a great deal better. A much wider sweet spot or to put it another way, little to none of the beaming problem that so aggravates me.

 

The fact a set of Imagine Bs costs slight yes than half the cost of a Synch C is just gravy though. And not having to mess with the 2chanel music setup *or* with a sub. (Grin)

[Audio_ELF]

My experience has been that a single speaker identical to your left and right is the best option ... Sadly practical considerations usually makes that impractical unless you are using a projector and an accoustially transparent screen.

 

Eloise

[sdolezalek]

My experience has been that a single speaker identical to your left and right is the best option ... Sadly practical considerations usually makes that impractical unless you are using a projector and an accoustially transparent screen.

 

Eloise

 

Eloise: When you say "my experience"I assume that means you have tried the single speaker vs the Tri center or dual center? I would agree with your experience that a matched identical center sounds better than a non-identical one. But my own experience has been that the Tri-Center, even with slightly mismatched (same brand, same dipole style, just smaller radiating surface) significantly outperforms an identical center speaker. I can't explain why, but listening tests by others have confirmed the same result. In addition, it may be different with dipole speakers than with box speakers.

[Bill Lord]

Our,video sound runs through our living room two channel setup. Increasingly, over me past year, Karen and I what've notices that dialog, while perfectly placed, is getting lost in overwhelming music tracks. This is much more noticeable with newer material on BR, and with Dolby Digital tracks from Netflix.

 

Paul

 

 

In the world of art and the subjective, no one is an expert- Recently, I was made known of the multi channel "mix technique" for various shows and movies has been optimized in a way that serves multi channel playback the best.

 

Perhaps the two channel only, solution is less optimal unless there is a specific two channel mix on the media you are enjoying??

 

I'm inclined to follow the same methods published for Mix/Mastering engineers, which is loosely the same speakers all around in their specific location. The only one open to interpretation of placement is the LFE channel.

 

You may find yourself with a multichannel system and a 2 channel system..

[Audio_ELF]

Eloise: When you say "my experience"I assume that means you have tried the single speaker vs the Tri center or dual center?

My experience being (in demonstrations) a trio of B&W 802 was better than 802 with HTM center and better than 802 with a pair of 805 for center. I also in my own situation tried a pair of 601 speakers was beaten by the LCR for center.

 

Perhaps the Mangepan is an exception to the rule.

[Kal Rubinson]

My experience being (in demonstrations) a trio of B&W 802 was better than 802 with HTM center and better than 802 with a pair of 805 for center. I also in my own situation tried a pair of 601 speakers was beaten by the LCR for center.

 

Perhaps the Mangepan is an exception to the rule.

I don't think so. I know that this entire discussion presumes that there is a screen on the wall and that the center speaker(s) need to accommodate it. I also know that the demos I have heard with multiple center arrays (including the Magnepan) usually are done with movies where the visual cues serve to enhance the audio localization. However, if you turn off the screen and play some music, it becomes apparent how this arrangement is inferior to a proper single speaker center.

 

That said, if your goal is HT, this arrangement can be effective. But not for me.

[Paul R]

I had really never thought of using a center channel speaker for music... though I guess I should have. When I listen to music, the center channel is not engaged, unless of course, it is a video of a concert or something. Even then, I am likely to play the stereo track.

 

Funny how little assumptions like that can make all the difference in one's perspective. I really understand what you are talking about now.

 

Are multichannel rigs used a lot for pure music listening, without the video?

 

-Paul

 

 

I don't think so. I know that this entire discussion presumes that there is a screen on the wall and that the center speaker(s) need to accommodate it. I also know that the demos I have heard with multiple center arrays (including the Magnepan) usually are done with movies where the visual cues serve to enhance the audio localization. However, if you turn off the screen and play some music, it becomes apparent how this arrangement is inferior to a proper single speaker center.

 

That said, if your goal is HT, this arrangement can be effective. But not for me.

[Kal Rubinson]

I had really never thought of using a center channel speaker for music... though I guess I should have. When I listen to music, the center channel is not engaged, unless of course, it is a video of a concert or something. Even then, I am likely to play the stereo track.

 

Funny how little assumptions like that can make all the difference in one's perspective. I really understand what you are talking about now.

 

Are multichannel rigs used a lot for pure music listening, without the video?

 

-Paul

Depends on whom you ask but I have no statistics. I have more than 2000 multichannel audio-only recordings and I have friends with similar collections.

[sdolezalek]

Are multichannel rigs used a lot for pure music listening, without the video?-Paul

 

Paul: I can't say "a lot," but that is now very much the way I listen to music. Of course, I have a large 5.1 channel SACD collection and both 5.1 and 7.1 BluRay discs that also benefit from this configuration. But I do think there is something unique about the Magnepans in this regard. Even when I'm listening to some of the best box systems, I'm always acutely aware of where the boxes are, whereas in my system you would have a difficult time finding the center array with your eyes closed. In part that may be due to a highly diffractive rather than absorptive backdrop to the front speakers. Lastly, I would add that my own listening tastes run strongly in favor of making me think that I'm there in the space where the performance occurred, over and above accuracy. As a result, although I can appreciate the crystal clarity of great headphones, i find it much harder to lose myself in the performance. So much of this may just be personal preference.

[realhifi]

My experience has been that a single speaker identical to your left and right is the best option ... Sadly practical considerations usually makes that impractical unless you are using a projector and an accoustially transparent screen.

 

Eloise

 

Which can work superbly if implemented properly.

[dc2bluelight]

The OP's setup, just considering the Magnepan L and R along with the room, the result will be a very large diffused sound field with only a general sense of localization. It's what figure-8's do best, along with their cousins, omnis. However, it's pretty much impossible to get a well defined and localized image out of that with all the deliberate reflections and multiple arrivals going on. What you get is a huge spacious soundfield without any real palpable localization, but it's impressive and pleasing to many. No doubt the only way a center will match that kind of presentation is to be similarly comprised of multiple arrivals and reflections, or lacking that, at least multiple arrivals like that from several sources. That's not going to happen with a single center, hence the preference for the tri-center. Then the center will approach a similar huge and spacious presentation of the L and R.

 

Just to point out something else, the screen and center location is highly asymmetrical in this case, the multi-center ends up an even better match.

 

However, if one builds a room more consistent with ITU 775, similar to the Dolby and THX recommendations, in a less reflective, more treated space with direct radiating LCRs rather that figure 8's or omnis, the single center is correct and will integrate far better. The choice of a center identical to L and R, or at least timbre matched, is also important in that layout.

 

To see why each configuration works you have to look at the total environment.

[Paul R]

(amusement) I am not quite sure what you are saying, and whether you are talking about video or music...

 

I know with what I am doing, I get a precisely pinpoint localized vocals that match what is on the video screen. With Maggies, it works, if anything, even better. Not entirely sure why of course, and I am speaking of video, not music.

 

-Paul

 

 

The OP's setup, just considering the Magnepan L and R along with the room, the result will be a very large diffused sound field with only a general sense of localization. It's what figure-8's do best, along with their cousins, omnis. However, it's pretty much impossible to get a well defined and localized image out of that with all the deliberate reflections and multiple arrivals going on. What you get is a huge spacious soundfield without any real palpable localization, but it's impressive and pleasing to many. No doubt the only way a center will match that kind of presentation is to be similarly comprised of multiple arrivals and reflections, or lacking that, at least multiple arrivals like that from several sources. That's not going to happen with a single center, hence the preference for the tri-center. Then the center will approach a similar huge and spacious presentation of the L and R.

 

Just to point out something else, the screen and center location is highly asymmetrical in this case, the multi-center ends up an even better match.

 

However, if one builds a room more consistent with ITU 775, similar to the Dolby and THX recommendations, in a less reflective, more treated space with direct radiating LCRs rather that figure 8's or omnis, the single center is correct and will integrate far better. The choice of a center identical to L and R, or at least timbre matched, is also important in that layout.

 

To see why each configuration works you have to look at the total environment.

[dc2bluelight]

(amusement) I am not quite sure what you are saying, and whether you are talking about video or music...

 

I know with what I am doing, I get a precisely pinpoint localized vocals that match what is on the video screen. With Maggies, it works, if anything, even better. Not entirely sure why of course, and I am speaking of video, not music.

 

-Paul

 

Video does tend to be an influence and make up for ambiguous audio imaging. Glad you like it, though.

[Paul R]

Video does tend to be an influence and make up for ambiguous audio imaging. Glad you like it, though.

 

I agree. The thing is, even given the possible issues, there is no ambiguous imaging at all. Better performance than any center channel speaker I have tried so far in fact.

 

The caveat being I do not use the center channel for music yet, as I don't really have any multichannel music. Yet. Things might (probably will) change when I introduce that into the mix.

[Paul R]

I should mention that I have been playing around with this quite a bit lately. Up close, anywhere within a couple feet of the speakers, the distortion Kal and Tony mentioned is very evident, well past the point of being unpleasant. Just as they predicted.

 

At our normal listening and viewing range (12 feet) in our specific room, the distortion is inaudible. This could be for many reasons, including being unique to our room. The listening position is well outside the point where the tweeters cross, forming a "superstereo" configuration. Or they would if they had any stereo content to present, which of course, they do not.

 

Using a single speaker as the center channel (talking a normal speaker now, not a specific center channel) still results in a bit of a beamed effect, and a bit of an unnatural sound, as well as greatly reduced bass output. This is true even when using the PSB Synch1Bs as the center channel. Both together sound wonderful, with crystal clear perfectly placed dialog. One by itself sounds- anemic and highly localized.

 

Currently have a legacy set of large Advents setup as the mains, and the pair of PSB Synch 1 Bs as the center channel. The PSBs and the Advents are both setup as "large" speakers, which I believe means bass signals are routed to them both. Though the Advents go lower (much lower) than the PSBs, any other configuration does not sound as good. This does not necessarily make sense to me, but it does bear out why we are not liking subs in this room at all. (We do love a sat/sub setup in a much more conventionally shaped room upstairs though. )

 

I have ordered up a KEF 600C center channel, and three less expensive but recommended models with a 30 day right of return. That would be the Level3 model from Home Theater Direct which has a folded ribbon horn loaded tweeter ($300), a Fluance conventional driver center channel for $119, and a Magnepan Center Channel MCCW ($299). We are also borrowing a Martin Logan Cinema center channel with a list price around $1600. That should give us a large range to compare to I think. We expect the KEF 600C might be the one that works the best here, but who knows?

 

Right at the moment, since the PSBs and the Advents blend so perfectly well together, we are not going to worry about voicing the speakers together. Since the mains, whichever ones they are at any moment, are a separate system for music (fed through a HT bypass when being used for video), I am not opposed to simply putting in a reasonable set of speakers just for the video and not using them at all for music. This is also recommended by people here and is certainly on the table!

 

Thanks for all the great opinions and ideas- I am certainly learning a lot and having a great deal of fun.

 

Paul

[mav52]

I've always tried to match my fronts with my center in my HT room to ensure the spec's matched as close as possible and from my experience movie soundtracks use the center channel heavily, and using my AVR to match levels provides for a seamless integration. But I'm talking about HT, and I use BG Radia speakers in my HT room.

[mayhem13]

Your experience is a perfect example of destructive interference and comb filtering. At a distance, the individual lobes created are much more diffused......but the nulls between them are also deeper so the result is a perception of a smoother response with less high frequency content.

 

Thank you for the real world feedback as this is where the thread truly becomes helpful to others who come across it for reference.

 

Twelve feet distance?.......is that you're viewing distance too?

[dc2bluelight]

I agree. The thing is, even given the possible issues, there is no ambiguous imaging at all. Better performance than any center channel speaker I have tried so far in fact.

I'm not challenging or questioning your preferences, just pointing out that if you compare your multi-center configuration with a person standing in front of your display talking, even without looking hard you can see there's a rather significant difference in the path(s) sound takes to get to a listener. If you think one is more natural, or lets say pleasing, than another, that's up to you.

The caveat being I do not use the center channel for music yet, as I don't really have any multichannel music. Yet. Things might (probably will) change when I introduce that into the mix.

 

...And, regarding imaging with two channels, just to point out, phantom images only exist with any accuracy of placement when the listening position is on a line perpendicular to a point exactly between the speakers, with channel levels matched, the speakers are exactly equidistant from the listener, the listener's head is pointed strait down that perpendicular line, and the acoustic environment around the speakers and between them and the listening position is nearly identical. Change any of that and you skew the phantom center, and ultimately all other phantom positions as well. Sorry, that's 2 channel stereo.

 

As you may know, the early stereo experiments performed at Bell Labs indicated that the minimum number of channels required for proper soundstage (they didn't use that term of course) was three (left, center, and right), with many more being much preferred. Their ideal system was hundreds of speakers in a vertical rectangular grid driven from hundreds of channels. Simply put, if you want a sound to come from "there", you need a speaker "there", or put up with a reduced listening window. The only reason we have two channel stereo today is practicality of distribution, it has nothing to do with accuracy or purity of recording and reproduction. Two channel stereo was a compromise when it was introduced, and still is. The most likely reason some people staunchly prefer two channel stereo is one of familiarity, and an errant supposition that because we have two ears, two speakers is a perfect match. But sadly, that's not the case.

 

Hope you enjoy your multi-channel music experiments soon as well, I know I do!

[mav52]

deleted

[Paul R]

Mayhem:

 

Yes, 12ft is the distance from the speakers where the bass is audible and the most natural. (Setup via Get Better Sound methods...)

 

The TV screen is centered between and about 18" behind the speakers. Due to the the slant range to the speakers, it is about the same physical distance.

 

There are areas in the room where the bass is totally cancelled out due to the ceiling slope. You can literally be standing 24" in front of a sub and not be able to hear it *at all* - while the pictures in the loft upstairs are shaking on the walls. Irritating.

 

Another reason why I tend to like Acoustic Suspension speakers is that the bass is not radiating up the back wall and winding up in the loft so much. Much nicer and less wearing on people who happen to be upstairs. Does this even with my much beloved Maggies of course.

 

DCBlueLight:

I am challenging your assumption that what we hear is totally preference and not factual. Standing in front of the television and speaking to a person at our accustomed listening and viewing location, human speech is much more natural and intelligable with two center channel speakers than with one. I make no assumptions as to why, just that it is so. (grin) I cannot explain it well either.

 

If I were to guess, I would say our room is not well suited for standard topology.

 

-Paul

 

Your experience is a perfect example of destructive interference and comb filtering. At a distance, the individual lobes created are much more diffused......but the nulls between them are also deeper so the result is a perception of a smoother response with less high frequency content.

 

Thank you for the real world feedback as this is where the thread truly becomes helpful to others who come across it for reference.

 

Twelve feet distance?.......is that you're viewing distance too?