Center Channel Placement- High or low?? - AVS Forum
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post #1 of 9 Old 12-29-2011, 08:30 AM - Thread Starter
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I am installing a very modest starter home theater. New Onkyo 5.1 receiver and have decided to try the in-wall monoprice 7604's for L-R-C speakers. I am using an OptomaHD66 projector on a DYI painted screen on the wall. All the components are modest and part of a basement HT project. The floor will be carpeted and the ceiling drywall painted a darker color.

Given the space, projector, throw and screen size and other variables I have to work with, here is my issue: The center can either go above the screen, but would be 84" off the floor or below the screen and would be about 22" off the floor. One seems to high and other too low? I am not using a seating platform for the couches. I'd prefer not to reduce the screen size to accommodate a better center speaker location.

I am thinking since the LOW placement would be closer to ear level and the carpet would help absorb the sounds that would "hit" the ground that LOWER is better than up above the screen? Either way I can center it left to right on the screen. Thanks for any suggestions.
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post #2 of 9 Old 12-29-2011, 08:46 AM
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If the tweeter doesn't swivel in those in-walls then I don't like either placement...... Personally I like the speaker below the screen aimed up at the listener but in your situation I think I would go for above the screen if the tweeter doesn't swivel. Cuz if you go below the sound will be hitting your legs.

Shawn
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post #3 of 9 Old 12-29-2011, 01:17 PM
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Human hearing is adapted for better vertical localization at or below eye level than above (presumably because most things that ate us were on the ground?). Your brain will attempt to pull the sound image up or down to match what your eyes see on the screen. Since sounds coming from above are more difficult to localize, it is easier for the brain to make this adjustment. The discrepancy caused by a localizable source down low and image higher up can cause listener fatigue.

Thus, all things being equal, above is better than below.

All things are rarely equal, however. 6" below might be much better than 6' above. Reflections from the ceiling might result in frequency and time domain issues that are even more problematic. Vertical response of many speakers is not symmetric, and the response above the tweeter plane might be superior to the response below. Etc. So each case is somewhat unique, even if starting from the "all things being equal" rule of thumb given above.

In order of preference, I'd say...
(1) acoustically transparent screen with equal LCR and at least center behind screen.
(2) acoustically transparent screen with conventional center channel speaker behind the screen.
(3) center above the screen if sufficiently far from ceiling, and not so far from L/R acoustic centers as to cause noticeable image shifting with pans
(4) center below if all other conditions are excluded

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post #4 of 9 Old 12-29-2011, 01:51 PM
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This might be one of the cases where having two centers - one above and one below the screen might make sense. Maybe.

Everything I say here is my opinion. It is not my employers opinion, it is not my wife's opinion, it is not my neighbors opinion, it is My Opinion.
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post #5 of 9 Old 12-30-2011, 02:12 AM
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+1 on what Bigus said, I'd like to add some food for thought.

First, have you already bought the in-wall speakers and ran wires to their location, or is this a planning stage thing and you are looking for information?
Not clear.

There is a sticky in this forum called Setting Up Your Home Theater Audio 101 , There is a speaker layout specific portion with a good easy read
Audioholics - Speaker Placement: Setup Tips for Upgraded Home Theater Systems

From that:
Quote:


Step 1: Center Speaker Positioning

First stick two rubber feet on the bottom front of your center speaker. Then place the pie shaped doorstops under the back of the center so the back is angled down toward the listening position. Next, place the laser pointer on the top of the center speaker pointed at the listening position. Then aim and adjust the beam of the laser pointer so it is just above the ear level at the listening position. Adjust the rubber door stops until the correct height is obtained. This effectively aims the tweeter at the listening position between your ears.


Step 2: Main Speakers Positioning

Position your front main speakers at least a foot off each back and side wall and you are close to the "Golden Triangle Rule" ( Example: speakers 8ft apart from listening position and 8 ft back). Make sure that the speakers are the same distance off the back wall with the tape measure, then place the laser pointer on the inside panel of the speaker enclosure at the height of the tweeter.

With the laser pointer beam active, rotate the speaker inward until the laser pointer beam is about 6" away (outside) from the center of your listening position. This will effectively toe in the speaker to a close position according to the dispersion patterns of your speakers. If your speakers have an unusually wide dispersion pattern, you may wish to experiment with the degree of toe in for optimal performance.

Speakers need to either be aimed at the MLP seats as described above, or if you have a AT screen placed behind the screen at appropriate location also considering the above.
Key is Front R/C/L should be close to ear level.
This thread at audioholics shows for "flat" screen HDTV not a big projection screen.
In-Wall Speaker Selection & Installation Basics
Quote:


Ideally the three front speakers (Left, Center, Right) should be placed at ear height (seated position)

IMO, your monoprice 7604 speakers are the wrong ones for your painted wall screen, they could go behind a AT screen, but are better suited for flat panel HDTV's.

Why sacrifice your HT audio experience after all the hard work you've done? (will do?)

Best thing would be to return them and consider in room speakers.
You'd still have the center located below the screen, but then could build/buy a center stand to angle the speaker at you, similar to what I did.


If you are really-really fixed on in-wall, then I'd consider to make the wall construction such that you could angle the sides towards the MLP and the center up, or look at other in-wall speakers that do that for you already.
I've not seen others do that, but there are so many threads here possible others have done it.
(Yea, some will say those in-wall speakers were not designed to be angled, there will be edge diffraction issues if you do that etc, hey I'm trying to give you information and options here)

Good luck.
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post #6 of 9 Old 12-30-2011, 04:49 AM
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If possible prep it for both and experiment.
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post #7 of 9 Old 12-30-2011, 06:03 AM - Thread Starter
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Thanks for all of the great ideas. I am at the framed, rough in wiring stage getting ready to drywall. Moving the speakers a little is pretty easy at this point, I left a good amount of extra wire and there is access to the screen wall from behind too if I really need to get to it later on. I quick mounted the projector last night to get more refined layout on the framed wall. I can get a max 92" screen and mount the center below the bottom edge of the screen and it will be 30", possibly 32" off the ground and not 22" that I had originally thought. This is much closer to ear level seated on the couch. I think based on the above that I will use the 7604 center elsewhere and look for a a center with an aimable tweeter. I don't think I will be that far off if I can install it at 30" and aim it up just a little? I will try the laser pointer idea, thanks for that one. My wife has some hearing loss so the dialouge/center speaker is important so I will stretch the budget a little if anyone can think of a center that had am aimable tweeter - I will go for it. After all, its for her... Thanks again for the help, trying to keep to a limited budget but not be penny wise and pound foolish. Its mostly a place to let the kids go and watch movies and do x-box and stuff in the basement and give us a chance to see if we like projectors and HT set-up. When I work on the upstairs HT room with a bigger budget, I want to have made all my "mistakes" downstairs and learn from them.
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post #8 of 9 Old 12-30-2011, 09:12 AM
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Keep in mind your front 3 speakers should be the same. If your getting a new center then get new L&R or it might be worse than keeping the front 3 you have now.

Sound is a science and can be a pain in the @$$ but the more you know up front the better your HT experience will be.

Shawn
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post #9 of 9 Old 12-30-2011, 09:48 AM - Thread Starter
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Thanks. I know that Monoprice is far from great, but they have a center with an aimable tweeter so I might go with that and see what it sounds like. I am sure the kids will still be wow'ed when the x-box and their movies have surround sound.... Hopefully it will also be good to watch family movies in as well. With access to the back of the screen wall I hope I can always upgrade the speakers if it turns out to be unacceptable.
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