Two Center Channels? Technical why...

[BMXTRIX]

I am trying to find out if it is a bad idea to run two separate speakers above and below a screen to help produce audio that truly seems to come from the center of the screen.

It was brought up as a possibility on another forum and I was thinking that this is a bad idea, but I don't know why it would be bad. Similar to ghosting a center channel by using L & R mains, but use an upper and a lower center channel to help lift the dialog to the center of the screen.

Any audio conflicts, etc?

Any recommended ways to accomplish this with excellence?

Would two matched center channels handle this admirably?

Thanks!

 

[Spiffyfast]

I think Brian ordered a second center channel last week from Ubid and was going to try that, don't think he has gotten it yet b/c mine shipped a few days before and I get my center tomorrow.

 

[brian32672]

Actually I was trying to find the site where THX allows for dual centers. I recall reading that the main reason is that the 2 are slightly angled so sound is reached the same throughout a movie room. Granted they are speaking of a huge area to cover. I'm still looking for that site. I know it was on a THX certification page, for movie theaters. And it went in depth on the acoustics.

 

[goodman]

...use an upper and a lower center channel to help lift the dialog to the center of the screen.

I don't think using a speaker at the top and the bottom of the screen would center the sound in the vertical plane, because your eye level is much closer to the bottom of the screen.

 

[brian32672]

I don't think using a speaker at the top and the bottom of the screen would center the sound in the vertical plane, because your eye level is much closer to the bottom of the screen.

This is certainly the case for a 16:9 screen. In my case its 4:3 at 120" So the lower one would be about 19" from the bottom of the floor. The one above would just have to be angled to the center listening position...

 

[DTRUTH]

I believe two centers were used for the 7.1 config in the AA Epic 80-600 review. One above and one below the screen.

 

[jaxvon]

Yes DTruth, Ray Adkins used two Axiom VP150s and achieved great results.

 

[BMXTRIX]

What about mixing speaker brands or sizes?

What about timing offset due to differences in distance?

What about reflections from speakers being located on different planes?

What about load differences on the receiver and how that would impact volume/levels?

About a month ago there was a guy looking to run two left and two right speakers for his mains, and he got kicked pretty hard in the teeth for it with lots of reasons why he shouldn't do it, but I'm not hearing any reasons why this would be a bad thing to do with a center channel.

 

[brian32672]

What about load differences on the receiver and how that would impact volume/levels?

This is why I would go with a seperate stereo amp for the centers...

What about mixing speaker brands or sizes?

I would say stay with 2 of the same, or there really would be acoustic matching problems.

 

[Privateer]

If you have the room you could run 10 center speakers if you wanted to.

 

[wilkenboy]

Cool concept... more speakers = more things to dream (scheme) of purchasing. I'd love to hear how it turns out...

What about mixing speaker brands or sizes?

You could probably get away with it, but you'd want them to be very close tonally so they would "mix" well and one wouldn't distract you from the other.

What about timing offset due to differences in distance?

Depending on your setup I don't think this would present much of a problem with destructive interference... at least at frequencies we can hear. If they were both relatively equidistant from the listening location.

What about load differences on the receiver and how that would impact volume/levels?

How would you wire this?

Have you seen Yamaha's "presence" speakers outputs? I wonder if they were trying to do something similar.

 

[jaxvon]

I think you could make it work as long as the center channels you used didn't have a ton of vertical dispersion. If they did, I could forsee sound cancellation and other nasty effects.

 

[9f9c7z]

What about mixing speaker brands or sizes?

What about timing offset due to differences in distance?

What about reflections from speakers being located on different planes?

What about load differences on the receiver and how that would impact volume/levels?

What about the fact that your two ears don’t hear the same? Or maybe better stated; our brains don’t process the stimulation on each ear the same. It’s not symmetrical, one ear usually hears at a higher volume then the other. Seems to reinforce Sumiko Audio’s claim that any auto adjusting for the above parameters is a waste. They claim you have to make those adjustments with your ears as the only guide. Sumiko only distributes the Primar pre/pros with the auto features disabled.

I thought the center channel was primarily for the voice of whatever character was on the screen?!? I have noticed some 5.1 programs have the voice only on the center channel, and some 5.1 programs have it with an emphasis on the center but spread across all three front speakers. I used the auto setup feature with my Parasound. Except for DTS material, I usually (but not always) end up pulling the center channel down about –4db to get the sound even across the front. Don’t know why but DTS stuff is always dead on the money.

 

[benolium]

7.1 or 9.1

Have you seen Yamaha's "presence" speakers outputs? I wonder if they were trying to do something similar.[/QUOTE]


I have read that the presence speakers are intended to "supplement" the sound from the front speakers (not neccisarily the "center" speaker) by adding those little details "behind the screen" intended to give a more movie-like experience. Only active in Yamaha's DSP modes. I'm going to hook up mine this weekend.

By the way....when I hook this up to a 7.1 does that make it a 9.1 sytem or a 7.1 1/2? with points for a nice try on the 9.1

 

[brian32672]

It would be considered a 9.1 system

 

[benolium]

It would be considered a 9.1 system

Scales tipped, thanks

 

[RMK!]

Dual Center Channel Speakers

I have been living with dual center channel speakers in my system for a couple of months now (see pic) and for multi ch music and movies this experiment has worked out quite nicely. I could not fit the center that matched my main speakers in my ET Center so I decided to try this, rather than hack the cabinet. I was worried about the much discussed phase and cancelation issues but did not notice any of these with my setup. With my combination of AVR (Denon 3805) and Power Amp (Sunfire TG 5 ch 200) I have the luxury of having separate amp channels driving each CC speaker. The result of this is no impact to the Ohm load of the speakers that would normally happen with parallel or serial wiring two speakers off of one amp channel.I am now convinced that this is a perfectly acceptable alternative to the single center channel speaker.