Center channel: performance or placement? Pick one.

EthicalEar

EthicalEar

Junior Audioholic
While still Horn Loaded, Klipsch Centers are limited by being horizontal MTM designs. It is a common flaw of all such horizontal MTMs to have poor horizontal dispersion due to the lobing that occurs between the two mid-range drivers. You would need to sit withing a 15-20º range of axis (left or right) in order to avoid uneven dispersion of anything below the XO point.
While I would ordinarily recommend a matching Center to the Mains (by brand and series), there are instances where a well matched Center can be had outside those parameters.
However, I don't think Martin Logan would be a good match as their AMT Tweeter is known to be a little finicky in it's own right.
220px-Fowler&Semi-Fowler_01.gif Or you could just adjust your chair. Hehe.
 
RedHotFuzz

RedHotFuzz

Audioholic Intern
Here is a guy that did it with the same Kilpsh center speaker and Ultra short throw. check this one for another Idea.
Sweet setup! He must be using a 90" or 100" screen to have his projector that close to the wall and vertically that close to the screen.

One of the projectors I'm looking at, using a 120" screen, needs significantly more distance in both aspects. Which would not allow me to place my center channel (or projector) anywhere close to the height he has his and still fit the screen on the wall vertically. As you can see below I need 8 feet between the top of the screen and the bottom of the projector. The ceiling in this nook is 8'10".

I could eliminate a lot of the problem by going with a 100" screen, but it's not worth it to me.

PSCO-Hisense-120l5f-R1.jpeg
 
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RedHotFuzz

RedHotFuzz

Audioholic Intern
While I would ordinarily recommend a matching Center to the Mains (by brand and series), there are instances where a well matched Center can be had outside those parameters.
However, I don't think Martin Logan would be a good match as their AMT Tweeter is known to be a little finicky in it's own right.
Do you have any familiarity with the Golden Ears SuperSat 60C? Similar form factor to the Martin Logan.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Ah, gotcha. What speaker are you using as your center?


It's a through wall design.



In this picture the speaker is upside down relative to the way it is mounted in the room. The drivers are actually at the bottom and not the top. So they are right above the screen.



The drivers are the 7" SEAS coaxial T18REX/XFC. The lower driver is the main driver. The upper driver provides the Baffle Step Compensation (BSC) for that location via active crossover and separate power amp. Coaxial speakers are prone to some HF irregularities due to reflections from the woofer cone. The tweeter in the upper BSC driver is fed a fill signal, to fill in a fairly deep audible dip in the response at 9 KHz. This latter part was tricky.

FR and impulse response in the current location.



The measuring mic rolls off at 15 KHz.
 
M

Mr._Clark

Audioholic Samurai
That is another option, but with a 120" screen the speaker won't be anywhere close to head-level. It would be 8+ feet off the floor. So putting the center channel on the floor actually puts it closer to ear-level than putting it above the screen.

I'll only have about 10" between the top of the screen and the ceiling inside the nook.
I put a center channel above the TV for one of my systems. The TV is above a fireplace and I wanted to get the TV as low as possible. The center channel is almost 8 feet above the floor and it is mounted at a downward angle so the axis of the center channel is directly at my ears when I'm sitting on the sofa watching TV.

I was somewhat apprehensive about putting the center channel above the TV. However, it has not been an issue at all. When watching TV I do not perceive any issues whatsoever concerning the location of the noise source. I guess it's conceivable that someone else might have an issue with it. YMMV.

Given that one's ears are at the same level when sitting upright facing forward, I doubt that the human brain can distinguish between different vertical center positions with great precision (See, e.g. http://www.cochlea.eu/en/sound/psychoacoustics/localisation).

I have no experience with projectors, but I assume they do not have features that would permit a horizontal (off center) position without effecting the picture? A brief google search developed an article (link below) that mentions horizontal shift of the projector but I have no idea if this is an option in your case.

 
M

Mr._Clark

Audioholic Samurai
I already own the JBL Studio 590s, so those will be my L/R. No matter what I get for the center it won't be a great match for the JBLs since JBL doesn't make a decent center channel in their Studio line for whatever inexplicable reason.
I have a JBL 520C in one of my systems. It's not terrible for the price, but it's far from perfect.

In that system the 520C is between a pair of BMR Philharmonitors. I sometimes wonder if the 520C's flaws would be less noticeable if it was in a system with less capable speakers. Right now it's the audio equivalent of having that cute cheerleader I knew in high school on stage between two supermodels.
 
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RedHotFuzz

RedHotFuzz

Audioholic Intern
I have no experience with projectors, but I assume they do not have features that would permit a horizontal (off center) position without effecting the picture?
Correct. And placement/positioning has to be absurdly exact, based on all the owner feedback I’ve read where it took them hours to get everything lined up correctly.
 
Pogre

Pogre

Audioholic Slumlord
I would go with a phantom center if having one means handicapping it right out of the box with poor placement.
 
RedHotFuzz

RedHotFuzz

Audioholic Intern
I would go with a phantom center if having one means handicapping it right out of the box with poor placement.
I will definitely try that. But isn’t phantom center literally poor (poorest?) placement for anyone not sitting dead center?

I suppose I could also consider an in-wall center speaker below screen, which I assume would be better than the thin on-wall speakers, though still not as good as a full-sized center.
 
Pogre

Pogre

Audioholic Slumlord
I will definitely try that. But isn’t phantom center literally poor (poorest?) placement for anyone not sitting dead center?

I suppose I could also consider an in-wall center speaker below screen, which I assume would be better than the thin on-wall speakers, though still not as good as a full-sized center.
Well its free n easy to test.

Good speakers with decent imaging can do a great job if you get the toe in and positioning right. When I turn my center off it's actually really hard to tell the difference until you start getting way off axis. I'd argue a lot better than a poorly positioned dedicated speaker. Of course that also depends on how poor the positioning is too. There's levels to it, lol. Give it a try and see what you think.
 
RedHotFuzz

RedHotFuzz

Audioholic Intern
Well its free n easy to test.

Good speakers with decent imaging can do a great job if you get the toe in and positioning right. When I turn my center off it's actually really hard to tell the difference until you start getting way off axis. I'd argue a lot better than a poorly positioned dedicated speaker. Of course that also depends on how poor the positioning is too. There's levels to it, lol. Give it a try and see what you think.
Well, if it works well it's actually the ultimate solution for my situation.
 
TLS Guy

TLS Guy

Seriously, I have no life.
I will definitely try that. But isn’t phantom center literally poor (poorest?) placement for anyone not sitting dead center?

I suppose I could also consider an in-wall center speaker below screen, which I assume would be better than the thin on-wall speakers, though still not as good as a full-sized center.
Phantom center depends on how good your speakers are. Some speakers if you move off dead center you localize to the nearest speaker, with others you would not know there was not a center speaker.

In this system for instance central image stays central no matter where you are in the room.




In my in wall system it is very hard to tell whether it is three channel or two. In fact my wife vows she can't tell the difference. In truth I only built and designed the center just for the experience of designing a three way center.

As I have said before, the BBC do not include a center channel in their multichannel feeds. Their view is that a center is a downgrade. I have to agree, that in more cases than not, it probably is a downgrade. If you have mains with really good speech clarity, that produce a good stable image, you really can save the expense of a center.
A center in a good system really does have to offer something that the mains can not deliver in terms of articulation and coverage of the room. Actually it really does require some design differences and approach, and yet blend seamlessly, and tonally perfectly with the mains. That is a very tough assignment.
 
RedHotFuzz

RedHotFuzz

Audioholic Intern
I've kinda always wondered why we really need center channel speakers, since with stereo the vocals almost-always perceive to be center of the left and right speaker, and I've seen very few HT setups where the center channel speaker is equal in any way to the tower speakers on either side. If phantom center will present well with the Studio 590 speakers, it will be the best fix for my dilemma.
 
S

shadyJ

Speaker of the House
Staff member
I will definitely try that. But isn’t phantom center literally poor (poorest?) placement for anyone not sitting dead center?
The question is how many times will you be listening outside of the sweet spot? How many listeners of the system will even care about that imaging?

A phantom center can deliver good imaging at pretty much just one listening position. A poor center speaker will provide imaging outside of the sweet spot, yes, but it will have crappy sound quality otherwise and will deliver subpar sound to all listening positions.

The only way to get good phantom center imaging outside of an equidistant position from the left and right mains is through time-intensity trading where you take some speakers with narrower dispersion patterns and position them with an hard toe-in to cross in front of the main listening position. Audioholics has a good youtube discussion of it here. The JBL Studio 590s may have the correct kind of dispersion pattern to pull that off, so it is worth looking into for yourself.
 
TLS Guy

TLS Guy

Seriously, I have no life.
The question is how many times will you be listening outside of the sweet spot? How many listeners of the system will even care about that imaging?

A phantom center can deliver good imaging at pretty much just one listening position. A poor center speaker will provide imaging outside of the sweet spot, yes, but it will have crappy sound quality otherwise and will deliver subpar sound to all listening positions.

The only way to get good phantom center imaging outside of an equidistant position from the left and right mains is through time-intensity trading where you take some speakers with narrower dispersion patterns and position them with an hard toe-in to cross in front of the main listening position. Audioholics has a good youtube discussion of it here. The JBL Studio 590s may have the correct kind of dispersion pattern to pull that off, so it is worth looking into for yourself.
Shady, that is not true. Good speakers will produce good imaging between the speakers throughout the room. Speakers that only image at one sweet spot are sub par designs. In fact that defect is one I particularly look for when auditioning speakers. What you are stating does happen with many speakers, but it does NOT have to, and should not.
 
S

shadyJ

Speaker of the House
Staff member
Shady, that is not true. Good speakers will produce good imaging between the speakers throughout the room. Speakers that only image at one sweet spot are sub par designs. In fact that defect is one I particularly look for when auditioning speakers. What you are stating does happen with many speakers, but it does NOT have to, and should not.
There isn't any mechanism that I know of where it would be possible for a stereo pair of wide dispersion speakers to have good center imaging at off-axis listening positions, regardless of any other attribute of the speakers. It would be in defiance of the way human hearing works, at least as far as I understand human hearing.
 
J

JengaHit

Audioholic
Are those JBL 590s a controlled-directivity design? If so, it might be worth experimenting with extreme toe-in and time-intensity trading. With the right speakers this will create a huge sweet spot with a stable and centered stereo image/phantom center for off-axis listeners. I have my Hsu CCB-8s set up like this (they're designed for extreme toe-in). The other day I stood 10 ft to the left and slightly behind the MLP and still heard--locked between L/R--a solid phantom center with crisp imaging and dialogue. (Another speaker ideal for time-intensity trading, according to a recent Audioholics review, is the Arendal 1723.)

Of course, if your speakers are wide-dispersion, time-intensity trading probably won't work. But surprisingly a listener on another forum recently reported trying extreme toe-in with his Emotiva T1s, and was able to lock down a phantom center that was stable for listeners for the width of his sofa. He wasn't clear though on how sharp the imaging was off-axis.

Another option, admittedly clumsy, would be to put the center on a stand in front of your projector and AV cabinet. You might then need to pull forward your L/Rs. Of course WAF, a small room, and aesthetics might make this impractical.
 
H

hypermodecrits

Audioholic Intern
In your circumstances, I would skip the center speaker. No center is better than a mediocre center. Just have the front left and right speakers handle center channel duty, they are more than up to the task.
I agree completely.
 
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