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Discussion Starter #1
I am currently in design phase for a new theater. I have been discussing center channel placement with my designer. I can go either above or below the screen.


The ceiling height will be about 8'. There will be two rows of seats, one about 10'from the screen and the other about 15' on a riser.


He is pushing for above the screen, tilted downward. I have heard it is preferable to be below the screen. Any one have experience with both these placements?


I appreciate your comments.
 

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Discussion Starter #2
anyone?
 

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My center is above my screen by necessity, but it sounds great to me. I perceive the sound as coming directly from the screen and that's the whole point.


Bobby
 

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Your designer's right. Above the screen is a better choice than below.
 

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Below is easier, definitely. Perforated screens are preferable from a sonic viewpoint, but difficult to pull off.


The reason that the above-screen placement is preferred when possible is that the human ear is better at localizing sounds that come from below ear level. We tend to not be able to locate sounds that come from above ear level. It furthers the illusion that the sound is actually coming from the screen.


It can cause some other problems, however... are your main speakers going to be close to the bottom of the screen? There can be holes in the soundstage when the main speakers are on the floor and the center channel is above the screen. This will be less of a problem for the first row, as the main channels will be relatively higher compared to ear level, but those sitting in the back row might be able to hear the difference.


It's all about figuring out which comprimises work best for you.
 

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Quote:
Originally posted by TheMadMilkman
The reason that the above-screen placement is preferred when possible is that the human ear is better at localizing sounds that come from below ear level. We tend to not be able to locate sounds that come from above ear level. It furthers the illusion that the sound is actually coming from the screen.
You may be right but this does not intuitively make sense to me nor could I find any thing that backed this up from multiple sources. Can you or someone explain better? I understand the timing that sounds reach each of our ears helps us figure out left or right. I understand that the shape of our ears help us determine up or down. I don't understand why we can pick out things better down. I don't really buy the caveman theory of ... because we had to worry about more animals attacking us from the ground.

Quote:
It can cause some other problems, however... are your main speakers going to be close to the bottom of the screen? There can be holes in the soundstage when the main speakers are on the floor and the center channel is above the screen. This will be less of a problem for the first row, as the main channels will be relatively higher compared to ear level, but those sitting in the back row might be able to hear the difference.
This makes perfect sense to me. I can EASILY see where having a center speaker significantly higher than the front left and right would sound unrealistic. I don't think a car traveling across my screen is going to to leap to the top...unless I'm watching the Dukes of Hazards!:D (Of course the main dialog will be from the center but I think we are talking about panning sounds).


It seems to me that the distance you are from the speakers make a big difference. If you are close to the speakers/screen (THX 36 degrees like) then it seems you would really tell the center is higher. If you are farther away then I can see where the difference would be hard to notice.


My current plan is to put my center below yet high as possible to the screen and put the front left/right at the same height.
 

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Do it right the first time. Place it behind the screen using perforated material!
 

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I have mine below by necessity otherwise the screen would be too low for the second row. I have in-walls with aimable tweeters, so we aimed it up. So far everything sounds great.
 

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Scott:


I don't know that I can immediately put my hands on the citations you're looking for. I did that about 2 years ago here. The references can be found in both psychoacoustic and medical texts/papers. As I recall, one reference was Bob Stuart. Indeed, in one writing, he used the term "vastly better" refering to 'above' as opposed to 'below'. None-the-less, directional sensitivity is greater below ear level than above.


Clearly, a significant difference in tweeter height between the center and L/R speakers would create adverse affects regardless of the direction of the difference (up or down with respect to the mains)...so raise the L/R speakers. As you observed, your distance from the speakers would make a difference...that difference can be easily observed since the angular difference decreases with distance.


A point to think about when placing the center channel is you must understand you are NOT hearing the speaker if something is between you and that speaker. Thus, in rooms with more than one row of seating, those in the second row will not hear the center channel speaker (they may hear center channel sounds; but, not from the speaker). As well, in several studies it was found the quality of the audio has a greater impact on our perception video quality than video quality has on audio. Any thing you do that will deliberately degrade audio will have a very significant impact on our perception of video quality, hence overall experience quality.


BTW, in Georgia the 'caveman theory' is no longer used. It is now biological change over time.
 

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Quote:
Originally posted by Dennis Erskine
Scott:


I don't know that I can immediately put my hands on the citations you're looking for. I did that about 2 years ago here.


A point to think about when placing the center channel is you must understand you are NOT hearing the speaker if something is between you and that speaker. Thus, in rooms with more than one row of seating, those in the second row will not hear the center channel speaker (they may hear center channel sounds; but, not from the speaker). As well, in several studies it was found the quality of the audio has a greater impact on our perception video quality than video quality has on audio. Any thing you do that will deliberately degrade audio will have a very significant impact on our perception of video quality, hence overall experience quality.


BTW, in Georgia the 'caveman theory' is no longer used. It is now biological change over time.
Dennis, thank you for taking the time to help explain. I will look a little harder for some materials and perhaps experiment but I'm not doubting it is true. It just went against my intuition and my daily experiences.



Your point about *needing* to hear the center directly makes perfect sense to me. I can understand that if your center is not within line_of_sight that you are not getting direct sound waves. Cleary almost all people can see the bottom of their screen from the 2nd row so that means they must be able to see at least 6"-8" below that point to "see" the mid-point of their center speakers cones. My 2nd row seating is 1 foot higher than my 1st row. I need to double check some angles.


The attached is the type of center speaker stand I'm going to build. (It's Jim Mc "The Stargate" http://www.ofoto.com/I.jsp?m=66116202303&n=1123730486 )
 

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wantin'atheater, I curse you :rolleyes: , since doing all this reading has lead me to now move my center above my screen and front left/rights up several feet off the floor (ie. building stands). Like I need another excuse to delay my completion date :p
 

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Hi Scott:


I had a similar problem in my hypothetical home theater. I've had a pull down 10'x8' screen for a few years and a 7.5' tall room, so I was limited to putting a horizontal center either above or below the screen. Below the screen is guaranteed to reflect off the floor, giving me comb filter effects. Since I tend to slouch on the couch, the angle of a speaker at the ceiling is greater (points down more than a speaker near the floor would point up) so because high frequency energy from a speaker is directional, there would be less of a comb filter effect just because of the speaker angle. Also on the ceiling I can mount 703 to absorb some of the reflected sound, whereas I can't do that on the floor.


Ultimately I cast all that aside though. And my current plan is what Marc Ye

recommended in this thread -- buy a perforated screen and build a frame and put the speakers behind it. For me this means I have to donate the old screen to my employer, and it makes my room several feet shorter. But it offers me the advantage of using three identical tower speakers for left/right/center, which should give more consistent sound anyway.


Regards

Bob
 

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Quote:
Originally posted by BasementBob
Hi Scott: Ultimately I cast all that aside though. And my current plan is what Marc Ye recommended in this thread -- buy a perforated screen and build a frame and put the speakers behind it. For me this means I have to donate the old screen to my employer, and it makes my room several feet shorter. But it offers me the advantage of using three identical tower speakers for left/right/center, which should give more consistent sound anyway. Regards

Bob
Thanks for the console and input. I'm using a $tewart 135" drop down with 4x3 matte sides that also drop down (IR) and I couldn't dream of getting rid of it. I've had it for close to two years and haven't watched a single movie on it because I'm still building.
It sits hidden out of view behind a 1' false wall. There are there are lighted posters that wall as well (ie. part of the look of the room before the movie.


Luckily my ceiling slopes up (see attached) from where the center is going to be so my reflections may not be so bad. I'll do the mirror trick or others to check it when I get it this all set up.


I'm glad to learn and adjust but there is a "point of diminishing return$"

 

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Discussion Starter #17
Thanks everyone for the input. Now I am very comfortable with the above screen placement and even better, growing more comfortable with my designers knowledge.


As for my main speaker placement, I do have enclosures to the left and right of the screen and will be placing my speakers in them, raised several feet off the ground (about mid-screen height.
 

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Quote:
Originally posted by wantin'atheater
As for my main speaker placement, I do have enclosures to the left and right of the screen and will be placing my speakers in them, raised several feet off the ground (about mid-screen height.
Very good design choice.


Also, I figured out that the above-screen choice was better before ever reading about it. My center channel is above my TV (don't have a dedicated HT room... yet) and when I was sitting on my couch I couldn't locate the center channel, but when I was laying on the floor with my head facing up I could hear exactly where it was coming from. I then read some info on it, and since then I've been a huge advocate of having the center channel above ear level when having it AT ear level is not possible.
 

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This is a very interesting thread. I recently upgraded from an old RPTV to a FP system. Although I currently have my CC mounted below my screen, I am in the process of remodeling my room and I could certainly move it above the screen. However, there would be additional compromises with this position as well. My L & R speakers are mounted on stands placing the tweeters at 40" above the floor. In its current "below the screen" position, my CC is slightly below the tweeters of the L/R speakers at 36". Placing the CC above the screen would place it 90" above the floor, and 50" above the L/R speakers.


My question is this: Which is worse, a 50" height differential between my L/R and my CC speakers, or the bad psychoacoustic of mounting the CC at or slightly below ear level?


I must say that I've been watching movies with the CC in the lower position for about a month now and I haven't noticed that the dialog seems inappropriately placed. I watched "The Patriot" last night and never found the dialog unconvincing or spatially incorrect. (Of course, that was before I read this thread. Maybe I will start to notice it now.) The one thing I have noticed is that sounds which pan across the front sound stage seem much better integrated now than when I had the CC on top of my old RPTV.


BTW, my only two options for mounting the CC are above or below the screen. I don't have enough depth to mount it behind the screen and my screen is not perforated. Also, I'm very happy with my current speakers and don't wish to change them, (Klipsch Forte's on custom stands and Klipsch CC

SS speakers).


Thanks for any thoughts on the subject.


Craig
 

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Quote:
Originally posted by craig john
I must say that I've been watching movies with the CC in the lower position for about a month now and I haven't noticed that the dialog seems inappropriately placed. I watched "The Patriot" last night and never found the dialog unconvincing or spatially incorrect. (Of course, that was before I read this thread. Maybe I will start to notice it now.) The one thing I have noticed is that sounds which pan across the front sound stage seem much better integrated now than when I had the CC on top of my old RPTV.Thanks for any thoughts on the subject. Craig
If it sounds "real" to you now then I wouldn't change it. "Listen" to your ears. What put me over the edge was my front row potentially blocking sound even with my 1' rise...or maybe more so my front row being so close that they would hear the sound coming from below.
 
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