Centre channel level for wide dispersion

[supervij]

After level-matching my speakers with the analog SPL meter, I usually bump up the centre channel level by 2 dB. Otherwise, the centre can be a little overwhelmed by the mains. But that's just for me, when I'm sitting dead centre. Or if I'm with one other person, the +2 dB is usually still fine.

But sometimes I have a bunch of friends over, and the seating area is wider than the speaker setup, i.e., left speaker to right speaker is 9 feet and the seating length is eleven feet. When I move over to a seat that's furthest out, the SPL meter will read a drop (obviously) in sound volume by 5 dB!

So my question to you guys and gals is . . . if this situation has happened to you, how high did you bump up the centre channel level to help out the people on the sides before it became objectionable for the people near the middle of the row?

cheers,
supervij

 

[TLS Guy]

After level-matching my speakers with the analog SPL meter, I usually bump up the centre channel level by 2 dB. Otherwise, the centre can be a little overwhelmed by the mains. But that's just for me, when I'm sitting dead centre. Or if I'm with one other person, the +2 dB is usually still fine.

But sometimes I have a bunch of friends over, and the seating area is wider than the speaker setup, i.e., left speaker to right speaker is 9 feet and the seating length is eleven feet. When I move over to a seat that's furthest out, the SPL meter will read a drop (obviously) in sound volume by 5 dB!

So my question to you guys and gals is . . . if this situation has happened to you, how high did you bump up the centre channel level to help out the people on the sides before it became objectionable for the people near the middle of the row?



cheers,
supervij

If you have people outside the sound stage often, I would move the mains 11 ft apart. I assume your center is an MTM on its side, that has just the wrong dispersion pattern. Is there any way you can turn it 90 degrees so it is vertical?

Personally I find a center channel even a half db loud very irritating, as it ruins the depth of the sound stage. I'm glad I don't have that problem.

I did find though, that may be the Radio Shack spl meter reads the center channel a little low. 2 db quieter than a Shure SM 80 phantom powered studio microphone. The readings I get from the Shure sound correct to me, so on that basis you would be 2 db hot already. However do what works. You obviously have to hear the dialog.

As I have said before the center speaker is a really crucial choice. I'm yet to hear a commercial one in a dealer demo that is up to the task. There likely is one out there, but most have a driver layout that is exactly wrong. I suspect that issue contributes to your problem.

 

[billy p]

The main problem is the as-c1 it's simply over matched by the as-f2's. As a matter of fact I had similar issues with my set up and I used the as-b2's in tandem. Unless you're sitting directly in front it is not a great performer therefore by always adjusting to gain to compensate will cause other issues for the listeners in front.

I now this didn't answer your question but... that is why we have members like TLS Guy.

 

[Nomo]

I guess I'm pretty much the opposite.
After calibration I tend to drop the center level by about 2db. To much, or maybe the right amount, of center channel bothers me. It seems to make the sound seem too narrow. When I have people sitting on the fringes of the room it seems that using the PLIIx or NEO6 sound fields where I can spread the center signal, dialog in particular, out to the mains is a bit more pleasing.

 

[MDS]

I don't increase the center level after calibration, but I also use PLII Music with the Center Width setting bumped up one notch to spread some of the center into the mains. It makes the front sound stage sound wider.

 

[jostenmeat]

Yo vij man,

I really believe the most sensible compromise is to have it perfect for the center seats. If you have it too hot for the center, then the audio will always be compromised for someone. If its perfect for the center, at least those people can enjoy that much. When movies are playing, you will always be at least one person, but much less often will you have the whole room filled with guests.

Of course, the ideal solution would be to have a vertical center speaker. Trust me, I've banged my head over compromised center performance from my HT. Due to both speaker design and specific drivers. I've researched various price points on various designs, and am simply in a holding pattern, indefinitely.

I perhaps look forward to inexpensive, experimental center speaker purchases, but that's iffy for now. Without spending on any speaker, the best I could do for performance is to have the speaker ceiling mounted. This is not going to happen though.

I have to say though, how many guests even notice? Of course if you invited us audioholics, surely some would notice, but of the overwhelming majority of sane and normal folks out there... Well, I simply hope the video quality, LFE effects, recliners, and alcohol will distract them enough. No one has mentioned any kind of complaint about center speaker performance. (I predict entirely different results if I invited all of you guys over!).

 

[TLS Guy]

Yo vij man,

I really believe the most sensible compromise is to have it perfect for the center seats. If you have it too hot for the center, then the audio will always be compromised for someone. If its perfect for the center, at least those people can enjoy that much. When movies are playing, you will always be at least one person, but much less often will you have the whole room filled with guests.

Of course, the ideal solution would be to have a vertical center speaker. Trust me, I've banged my head over compromised center performance from my HT. Due to both speaker design and specific drivers. I've researched various price points on various designs, and am simply in a holding pattern, indefinitely.

I perhaps look forward to inexpensive, experimental center speaker purchases, but that's iffy for now. Without spending on any speaker, the best I could do for performance is to have the speaker ceiling mounted. This is not going to happen though.

I have to say though, how many guests even notice? Of course if you invited us audioholics, surely some would notice, but of the overwhelming majority of sane and normal folks out there... Well, I simply hope the video quality, LFE effects, recliners, and alcohol will distract them enough. No one has mentioned any kind of complaint about center speaker performance. (I predict entirely different results if I invited all of you guys over!).

Well, I think everybody has to be able to follow the dialog. If there can't follow the movie, they might as well pass out on his beer!

If anyone wants the plans of my center speaker, I will have a set copied at Kinko. They are on large pieces of draft paper. It has excellent coverage over the whole room. It is good for music and speech. If your mains are neutral they will match. They have no shout at all. Speech has a natural conversational quality without being in your face. They will work equally well vertical or horizontal, but if they are horizontal, they will need to be off center, so the main driver is centered.

 

[jostenmeat]

Well, I think everybody has to be able to follow the dialog.

Well, I have no argument there.

If there can't follow the movie, they might as well pass out on his beer!

Hmmm, you might have a real point here. This has happened more than once at my place!

If anyone wants the plans of my center speaker, I will have a set copied at Kinko. They are on large pieces of draft paper. It has excellent coverage over the whole room. It is good for music and speech. If your mains are neutral they will match. They have no shout at all. Speech has a natural conversational quality without being in your face. They will work equally well vertical or horizontal, but if they are horizontal, they will need to be off center, so the main driver is centered.

Wow, Id be quite interested. However, I have very serious limitations on height, unfortunately, and from what I remember seeing in your pics before, I don't think it has any chance of fitting. Too bad really. In fact, the latest idea was to check out KEF horizontal coaxial center speakers (in order to reduce height even further w/o top mounted tweeter). That's very nice of you to offer in any case...

 

[chas_w]

AS-C1 Lobing

I would say the problem is definitely a lobing issue with the AS-C1. I experienced this myself years ago when I owned the AS-F2/AS-C1 fronts. Sound and Vision also confirmed the "heavy lobing" of the AS-C1 at listening positions more than 15 degrees off-axis:

http://www.soundandvisionmag.com/assets/download/11102003154347.pdf

When running the Athenas I was able to help the problem by replacing the AS-C1 with a single AS-B2 bookshelf speaker.

 

[TLS Guy]

I would say the problem is definitely a lobing issue with the AS-C1. I experienced this myself years ago when I owned the AS-F2/AS-C1 fronts. Sound and Vision also confirmed the "heavy lobing" of the AS-C1 at listening positions more than 15 degrees off-axis:

http://www.soundandvisionmag.com/assets/download/11102003154347.pdf

When running the Athenas I was able to help the problem by replacing the AS-C1 with a single AS-B2 bookshelf speaker.

That's what I thought. Also the response at crossover of those towers is pretty rough. A nasty peak and and valley, that certainly will not help getting nice even room coverage. If Tom's measurements are correct, I would think that 2KHz peak is pretty unpleasant.

 

[bpape]

Have you treated the bottom end with treatments? Dialog is very easily masked by overly long bass decay times and buildup. As you approach the sidewalls, the bass buildup is worse.

Bryan

 

[supervij]

Well, I turned the centre channel on its end. It stood tall on top of the TV, and honestly, I thought it looked a little silly. In fact, I thought it looked ridiculous and would be visually distracting while watching a movie. But I called my roommate in, and asked him if he noticed anything different. He didn't even see it. Then when my friends arrived later, not one of them commented on it. So while I think it looks dumb, my non-HT obsessed friends were oblivious to it.

I know that placing an MTM centre speaker flat is just about the worst way to go, but I'm working with what I have here. chas, thanks for that link. The 15 degree angle is good to know. Very good to know, as that 15 degrees covers the whole couch. And most of the time, those are the only people watching TV. It's only on the rare occasion (a few times a year) that I place seats on either side of the couch, so it's only on those few times that I'll have to turn the centre on its end.

So I guess I've solved my problem. Thanks, everyone!

Oh, and just to answer a few questions . . .

I need to bump up the centre by a couple dBs, cos the Athena F2s can really overwhelm the C1, as billy mentioned. The first week or two I had them, I kept them level matched, but the dialogue was a bit hard to understand. Two dBs up, and everything was shiny.

Using PLII music is fine and dandy when it's a stereo signal that's being processed. But it's a 5.1 (or 6.1) signal I'm concerned with. I didn't think there was a centre width adjustment I can make for that, but I'll take a look in my manual again.

josten, it may not be something that's definitely noticeable, maybe it's more of a subconcious thing. No one at my little movie nights have ever mentioned it, certainly. But I do want to make it the best possible experience for them.

Bryan, I have no treatments as of yet. I really would like to, but I just haven't gotten around to it yet. I believe it would help, but there are other areas of my life right now that could use the money more!

Thanks again, all!

cheers,
supervij