Front & center placement? - AVS Forum
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post #1 of 12 Old 01-28-2011, 11:00 AM - Thread Starter
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Hi,

Trying to figure out my new setup with a ceiling mounted projector screen and wall mounted tv behind.

I have read that, especially the center speaker's front edge, must be aligned with the front edge of the TV/screen.
But if i do so, it will stay behind of my pj screen and that wont work.

Will it cause any acoustical problems if i align my center and front speakers back faces to my pj screen (basically putting the speakers in front of the screen)?

cheers..
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post #2 of 12 Old 01-28-2011, 02:26 PM
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That should be fine.

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post #3 of 12 Old 01-31-2011, 03:10 AM - Thread Starter
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Thanx for the answer Kal.

I have another question tho;
There is only 18" of height from the floor to the bottom of the screen when it is open, and i have to fit the center in there somewhere.

I have read that, for best effect, the center should be on the ear level, or near the heights of the front channel tweeters, but that is not an option in my situation.

My center is almost 9" high so that leaves me 9" of clearance from the floor.
I can tilt its front according to my seating position but what i wonder is, will the sound be disturbed too much being that close to the floor?

Besides ear height, what might be the minimum height a center speaker should be off the floor for acceptable performance?

Thank you...
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post #4 of 12 Old 01-31-2011, 06:45 AM
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No answer. Ear height is best and the farther from that the farther from optimal, even with aiming at the ear. Also, proximity to the floor will affect FR. You will have to live with your constraints.

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post #5 of 12 Old 01-31-2011, 07:56 AM
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Above the screen is preferred over below unless screen and ceiling height make that impossible or if the mismatch to L/R is vastly worse than mounting below. Human hearing is better at vertical localization at or below ear level than above. Mounting the center below causes a conflict in what our brains see and hear and it can be fatiguing. Mounting above makes it easier for our brain to accept what our eyes tell it and thus the soundstage is more stable and leas fatiguing.

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post #6 of 12 Old 01-31-2011, 08:35 AM - Thread Starter
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Sadly i can't mount on top of the screen, that will be on the ceiling, at 8' 4", which is a tat too high i think.

"You will have to live with your constraints"
In that case, i have to put it as i described and live with it
Hope it will not sound horrible to a first time semi dedicated HT owner..

Thanx both for the info..
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post #7 of 12 Old 01-31-2011, 09:13 AM
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Your center is perfectly fine that low and angled up to your ears 99% of the installs we do are that way just treat your room properly and it will sound awesome. As for the center being above the screen it is ok with a tv but never in our 15 years of building custom theater rooms have we put it above the screen in a projector setup we tried it once but the reflection on the ceiling is terrible and very hard to treat.
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post #8 of 12 Old 01-31-2011, 01:44 PM
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What I've found, this mounting of the mains down low doesn't make much sense.

In my experience, mounting closer to the ceiling aimed down, would be preferable than down low closer to the floor aimed up. I feel strongly that similar to soffit mounted studio mains, LCR mains in a HT environment are much more versatile config'd in this manner, and they sound better as well. I don't know whether it's a carry over from studios or live work, but I enjoyed vastly superior performance covering the room this way. I can appreciate extensive measurements for system optimization, however subjectively, I much prefer a speaker's axial response in the region somewhat above ear level than somewhat below ear level. A simple test is to tilt your head forward a little to increase apparent HF response.

Kal, you've posted quite a bit regarding hearing, perhaps you could elaborate on this as I've got no technical evidence. Also, it's more a function of the relative angle, more-so than the height. Merely using a numerical height of the speakers is meaningless unless accompanied by a listening distance. Then the subsequent product is the relative angle at which is formed between the listener and the LCR mains. Additionally, and even more importantly, is the issue of coverage. Coverage, a live sound term, is specifically important here because this is potentially a multi-seat, multi-participant experience. Each listener, needs to be able to clearly view the MF/HF elements of the speakers to allow for unimpeded propagation to their ears. If the front speakers are down low, then unless there is a extremely steep, row to row floor pitch, anyone not seated directly in the front will not receive the proper direct sound of the mains.

Any thoughts?





Good luck

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post #9 of 12 Old 01-31-2011, 04:18 PM
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Quote:
Originally Posted by motoharu View Post

Sadly i can't mount on top of the screen, that will be on the ceiling, at 8' 4", which is a tat too high i think.

"You will have to live with your constraints"
In that case, i have to put it as i described and live with it
Hope it will not sound horrible to a first time semi dedicated HT owner..

Thanx both for the info..

That's a shame. But I can't help but wonder... a 70+ inch tall screen? In a room with < 9 ft ceilings?

Just what are the dimensions of your room and screen?

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post #10 of 12 Old 01-31-2011, 05:10 PM - Thread Starter
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Room dimensions are, 33' - 20' - 8,4'.
However due to large columns and half of the room being used as home office, the planned HT section is 20' - 13' - 8,4'.
Screen is Da-Lite tensioned 133'

Now (Half of the room) Screen&Dimensions


TV


PJ (Actual Size)


If i do not put the top curtain i will have nearly 2' from the floor to the screen, but that thing will cover the lights, boxes of screen & black curtain at the back, plus i think it completes the look, so i want to kinda do it.

Another attempt, this time PS (no actual size)



Wiring
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post #11 of 12 Old 01-31-2011, 06:47 PM
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Quote:
Originally Posted by FOH View Post

Kal, you've posted quite a bit regarding hearing, perhaps you could elaborate on this as I've got no technical evidence. Also, it's more a function of the relative angle, more-so than the height. Merely using a numerical height of the speakers is meaningless unless accompanied by a listening distance. Then the subsequent product is the relative angle at which is formed between the listener and the LCR mains. Additionally, and even more importantly, is the issue of coverage. Coverage, a live sound term, is specifically important here because this is potentially a multi-seat, multi-participant experience. Each listener, needs to be able to clearly view the MF/HF elements of the speakers to allow for unimpeded propagation to their ears. If the front speakers are down low, then unless there is a extremely steep, row to row floor pitch, anyone not seated directly in the front will not receive the proper direct sound of the mains.

Any thoughts?

I do not know what our spatial resolution is with respect to the vertical plane but I do think that some things are relevant to this matter.
1. Whichever position, above or below, is closer to the horizontal plane of the main L/R speakers is preferable in minimizing anomalies with horizontal panning.
2. The floor is usually carpeted and that minimizes reflections in the range of most acute hearing, around 3kHz.
3. The higher position is advantageous for coverage, especially for multiple rows.

So, I do not think it is all black-and-white.

Kal Rubinson

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Senior Contributing Editor, Stereophile
http://www.stereophile.com/category/music-round

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post #12 of 12 Old 02-01-2011, 08:27 AM
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Quote:
1. Whichever position, above or below, is closer to the horizontal plane of the main L/R speakers is preferable in minimizing anomalies with horizontal panning.
In my example, the LCR mains being in a horizontal plane was a given. You're absolutely right, for continuity wrt motional imaging in the horizontal plane, the closer to being in a line the better... no question. So much so, I feel above all else, line 'em up above the display.




Quote:
2. The floor is usually carpeted and that minimizes reflections in the range of most acute hearing, around 3kHz.
I agree, however at 3k, an approx. 4" wavelength with a minimal angle of incidence from low mains, isn't going to be attenuated much by carpet. Perhaps a little specular diffusion more so than attenuation. Regardless, I again used a minimally treated room as a given.




Quote:
3. The higher position is advantageous for coverage, especially for multiple rows.
Nuff said.




Quote:
So, I do not think it is all black-and-white
You're right, it's not ... just shades of compromise.

As I peruse system pics, so, so many systems could use a few positional tweaks that should yield great results. I'm sure I'm not alone in this regard.



Thanks

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