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Discussion Starter #1
Hi, I post the same question at the "Speakers Forum" but didn't get too many answers. I will try it here.

I am still in developing my basement, therefore I have the option to change the layout of the rearwall, the rearwall is about 13' wide and 7' 8" high.

1st option: Have the HT entrance in the middle of the rearwall, that means the three rear surround speakers will be about 7' above ground. Is this too high?

2nd option: Push the HT entrance close to the sidewall. That way I can lower the spearkers to any height but the rear surround speakers will only be 3' 6" apart from each other. Is this distances between the 3 speakers enough?

3rd option: Push the HT entrance to about 2' from the sidewall, then I can install the center rear in the middle and the two rear surround spearkers about 1' away from the sidewalls.

Question is which option is better for sound?

Thanks in advance

Ken

:confused:
 

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There is a lot of information out there but I go with what the dolby site states and my Denon receiver manual. You mentioned 3 rears so I assume you are talking about a THX-EX and DTS-ES system with only 1 rear (vs 2).


Here is a link to the dolby site.

http://www.dolby.com/ht/Guide.HomeTheater.0110.html


For the sides, 2-3' above your sitting position ears directly to your left/right (some like slightly back).


For the rear, put it dead center in the back. I use 2 speakers and have them 110 degrees apart from each other from the center sitting position in the back row. [edit] This also goes the same height as your left/right surrounds...2-3' (or 1 meter as some manuals say). [/edit]


That should get you started.
 

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Discussion Starter #3
ScottF200, thanks for answering. I didn't make myself clear enough on the first post. I am installing a 7.1 setup. The dolby site does not indicate the 6th and 7th and the rear center placement, that's why I post here. Thanks for the site though.

Ken
 

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Actually, with only one rear surround, you are installing a 6.1 setup. In a Dolby Ex and DTS-ES setup the 6 and sometimes 7th speaker is/are the rear surrounds (rear center as you refered to it as). The other two speakers in the back of the room are the smae ones from a 5.1 setup, however in a 6.1 or 7.1 setup they are more commonly refered to as the "side" surrounds. Hopefully this claries things for you.


I think for your room the 3rd option you listed will get you the best results. However, speaker height is important so take ScottF200's advice and do some searching on the Dolby, DTS and THX sites to get speaker placement requiremnts.


Here are a couple of links:

http://www.thx.com/mod/techlib/surroundEx.html

This one provides an isometric view of a 7.1 setup
 

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Discussion Starter #5

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Sorry for the 110 degree reference. That was another speaker placement number that was stuck in my head (5.1 side placement). I looked up my Denon manual this time and was reminded it was 60 degrees. See attached pictures from my Denon 5800 receiver manual. HTH
 

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Here is the text that goes along with those pictures.
  • If the surround speakers are direct-radiating (monopolar) then place them slightly behind and at an angle to the listening position and parallel to the walls at a position 60 to 90 centimeters (2 to 3 feet) above ear level at the prime listening position.


    When using two surround back speakers, place them at the back facing the front at a narrower distance than the front left and right speakers. When using one surround back speaker, place it at the rear center facing the front at a slightly higher position (0 to 20 cm) than the surround speakers.


    We recommend installing the surround back speaker(s) at a slightly downward facing angle. This effectively prevents the surround back channel signals from reflecting off the monitor or screen at the front center, resulting in interference and making the sense of movement from the front to the back less sharp.
 

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Due to my room, I have to ceiling mount my surrounds. I'm

planning for 7.1. My rear wall is ~14ft back from my primary

listening position. The Dolby site gives an ide of what height

and at what angle, but how far behind the primary listening

position should I place the 2 rear surrounds?
 

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Discussion Starter #9
drjrt, there was not much information on that. But I recalled I'd read something like 2' - 3'. I am thinking if you use dipole/bipole then I don't think it makes that much of differences.

ScottF200 thanks for the info. I found the samilar info from the THX site.

Thanks

Ken
 

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Quote:
Originally posted by drjrt
Due to my room, I have to ceiling mount my surrounds. I'm

planning for 7.1. My rear wall is ~14ft back from my primary

listening position. The Dolby site gives an ide of what height

and at what angle, but how far behind the primary listening

position should I place the 2 rear surrounds?
One method would be to see where 60 degrees ends you up at (see previous JPG attachment). Use a protractor or some other means and some masking tape (or 2x4's) to extend the lines. It'll gets you pretty darn close. Then use a plumb bob to locate the area on your ceiling.


Also the Denon text states "place them at the back facing the front at a narrower distance than the front left and right speakers" from my previous post.


The denon page suggest the same even if you use xxpole speakers.


ROTs - rules of thumb from professionals (denon, etc) that are better than a dart!!!
 

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Thanks.


I had gotten my old protractor out and have lines everywhere -

I guess I will keep the rear speakers a foot or 2 closer to the

center line than the L and R surrounds. I'll probably secure them

to the closest floor joist since I don't want them falling on any

by-standers!
 
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