I currently have a 7.1 setup and I was thinking about upgrading to a better center channel and was wondering can I run two sets of wires to the center channel connector to back of the receiver so I have one center channel at the bottom of the TV and one at the top of the TV or am defecting the purpose of the center channel?

You can, but you'll be introducing a lot of problems (like comb filtering) that weren't there before. Do a search on two center channels and you'll find a lot of information.

You can, but you wouldn't want to. Search function, has been discussed repeatedly in the past.

I have pre-amp outputs on my receiver. I have a Y adapter from the Center pre-amp output going into both channels of an external amplifier and I run my two center speakers off of that amplifier.

It works pretty well, and I push my center speakers hard.

It's not really a good idea for the reasons mentioned above.

Bryan

I use dual bookshelves above and below the tv with no issues.

With a big screen, I like the imaging of two identical centers above and below the screen a lot better than having a single one either much higher or much lower than the L&R. The comb filtering thing is a strawman as long as everybody is sitting with their ears at about the same height and you adjust the speakers front to back so both tweeters are the same diagonal distance from your ear. People who have never heard a setup like that should try it sometime. It measures fine and it sounds great.

About the wiring, I'd wire them in series rather than in parallel to keep from overloading the amp with too low an impedance.

(amp +) --- (+ speaker1 -) --- (+ speaker2 -) --- (- amp)

With a big screen, I like the imaging of two identical centers above and below the screen a lot better than having a single one either much higher or much lower than the L&R. The comb filtering thing is a strawman as long as everybody is sitting with their ears at about the same height and you adjust the speakers front to back so both tweeters are the same diagonal distance from your ear. People who have never heard a setup like that should try it sometime. It measures fine and it sounds great.

About the wiring, I'd wire them in series rather than in parallel to keep from overloading the amp with too low an impedance.

(amp +) --- (+ speaker1 -) --- (+ speaker2 -) --- (- amp)

Hi Dennis,

I agree that stacked centers don't have the same degree of problems as horizontally oriented dual centers, for the reasons you allude to.

Here's a profile of my setup.

http://mysite.verizon.net/res8ycu4/sitebuildercontent/sitebuilderpictures/profile4.gif

Balancing the potential for comb filtering problems there are other very tangible benefits of my stacked arrangement, not the least of which is exceptional dialog intelligibility. The upper center speaker can send sound to the rear seating unobstructed by the seating and people sitting in the first row.

Here's several threads which discuss the pros and cons of the arrangement.

surround speaker placement w/two rows of seating (http://archive.avsforum.com/avs-vb/showthread.php?postid=4267283#post4267283)

Stacking Dual Center Channel Speakers? (http://archive.avsforum.com/avs-vb/showthread.php?threadid=424858&perpage=20&pagenumber=1)

center placement (http://archive.avsforum.com/avs-vb/showthread.php?postid=4134863#post4134863)

Multiple rows of seats and center channel? (http://archive2.avsforum.com/avs-vb/showthread.php?p=7766734&&#post7766734)

Is it true that most sounds in movies and most music can't sustain room modes? (http://archive2.avsforum.com/avs-vb/showthread.php?p=6520435&&#post6520435)

Like tscoff I run the line level out from the center channel of my preamp to a Y connector and then to each input of a stereo power amplifier. Each center speaker gets its own channel of amplification and there's no need to worry about parallel wiring considerations overloading the amp, or series wiring attenuating the voltage delivered to the second speaker.

Larry

I've done installs where the TV monitor is positioned such that two centers,one on either side of the monitor made a much better option than no center (phantom) or a make shift above or below.

There are alot of taboo in audio and you have to weigh it up.Use your ears.if it sounds bad don't do it.

I have posted many times, questions on what all these types of distortion sound like. Comb filtering has to do with the position of your head and if you move your head the sound will go up and down due to the uneven nature of the signal from speaker.Sometimes it is very easy to pick it up, sometimes not.

Alway experiment before you dismiss an option.It has led me to many satifying installs for me and customers.

KG

One is enough that’s like saying can I have two left channels and two right channels sigh. One should suffice if you knuckle down and think!

I currently have a 7.1 setup and I was thinking about upgrading to a better center channel and was wondering can I run two sets of wires to the center channel connector to back of the receiver so I have one center channel at the bottom of the TV and one at the top of the TV or am defecting the purpose of the center channel?

Hi,

This is obviously a controversial subject with concerns related to comb filtering being balanced against a few practical considerations.

I feel the value in going to dual stacked center speakers has a lot to do with the constraints of your display configuration and the amount of seating, i.e. multiple rows of seating.

For example, in my situation I choose not to go with an acoustically transparent screen because I feared compromising the image. Therefore, since my screen is 10 feet diagonally, that meant I had to space my main speakers about 13 feet apart, leaving a large sonic hole for a single center channel speaker to deal with. By using two identical center channel speakers, that timbre matched my mains, I was able to seamlessly fill in that sonic hole while providing that all important center channel with ample power.

By properly arranging the dual centers I am able to project a phantom center image that stays anchored vertically on the screen regardless of where the listeners are seated. By the way, this is is not the case with horizontally oriented dual centers. In such an arrangement members of the audience sitting off-axis would find the sound erroneously shifted to the closer speaker. Likewise, the distance between each speakers to each listener would be different, except those few lucky individuals seated on-axis. This would mean, in theory, most listeners would be more likely to be subjected to possible comb filtering distortion due to the large delay caused by the different speaker distances. In contrast, with stacked centers everyone in the room remains almost equal distances from both center speakers, thereby reducing comb filtering concerns.

Having said this, I don't recommend using dual centers, stacked or otherwise, if your TV is modestly sized and your main speakers are spaced fairly close to the TV. There probably would be no compelling need to have two centers in such a configuration. In addition, while there is nothing wrong with upgrading your center channel speaker, its probably not ideal to use two different center channels together for reasons of level balancing and timbre match.

As I mentioned, having an upper mounted center channel is a big plus for multi-row theaters to ensure that everyone in the theater is getting unobstructed sound. This is very important to ensure dialog intelligibility. In some cases a single upper mounted center channel might be sufficient, however, if the front row of seating is fairly close it might result in dialog and other on-screen sounds appearing to come from the ceiling, rather than centered on the display. In that case a second lower center channel might improve things, despite the potential for comb filtering.

If you haven't already done so, I encourage you to read the other threads I provided.

Good luck.

Larry

One is enough that’s like saying can I have two left channels and two right channels sigh. One should suffice if you knuckle down and think!
Sure, knuckle down and think about how good it sounds when people are speaking from the floor or the ceiling and pans do a giant down-up-down whoopdedoo. That will sound great -- who'd want the sound to seem to come from the center of the screen? :)

Another solution is to add presence speakers ( yamaha rx-v663 etc) I have found that for me this solved all the dialog from below the screen problems. Now I have dialog staged in the center of the screen ( 135 inch 16x9 ) that is clearly understood in all three rows of seats.