Aid with optimizing acoustics

[Apedemak21]

Hi,

I am trying to put together a nice big projection screen entertainment centre with some great sound in my basement. As I understand room treatment is the best addition to increase the quality of the sound and I would like to spend some energy optimizing the 7.1 sound quality. The gear is half mine and half inherited:

Onkyo tx sr705 AV receiver
front speakers-Polk RTi 10s
centre - Polk CSi40
rear speakers - Polk RT12s
Surrounds on stands- Polks,bi-directional I’m not sure what they are, they came with the RT12s
Subwoofer-Polk PSW150

I am worried about the room as it is an odd shape with stairs and a hallway on one side and an offset half a hexagon bit on the other. The carpet is not in yet, but there is drywall up and it has a hanging ceiling. I can do pretty much whatever I want in the front part of the room without any wife complaints as long as it isn't too expensive. So, my query to all of you experienced folk is what can I do to the front half of this room to make my system shine? Any direction will be appreciated, thanks.

-A


Image-all measurements in feet, location of the speakers is just what I understand of 7.1 placement.

 

[Apedemak21]

I’ve been reading some more and I thought I should narrow down to some more direct questions and add that I would like to construct everything myself.

The things I think I should do is to treat the entire front wall to deaden it as much as possible especially since it has cement behind it. The two side walls are nice flat drywall and should so be treated to destroy their reflection abilities. And place bass traps in the front two corners.

Because of the shape of the room is treating the front and two side walls going to reduce indirect sounds and improve sound in this space given the odd shape?

 

[Glenn Kuras]

Yes everything you are thinking of doing is pretty much on the money. Not sure if you have to deaden the whole front wall, but some people like that sound so that is up to you. But besides the things you have noted I would also put a few panels on the back wall to help with the nasty nulls you are going to get off of there. In fact if money is tight I would still treat the front wall but replace the "whole front wall concept, with a few up front behind the speakers and a few on the back wall. For the back wall you will need something that is 4” or more thick to help with the low end.

Glenn

 

[mouettus]

Onkyo tx sr705 AV receiver
front speakers-Polk RTi 10s
centre - Polk CSi40
rear speakers - Polk RT12s

10s for the front and 12s in the back?! You should switch them out.
And all that on a 705?! You must be lacking power somewhere.

 

[Apedemak21]

The loudspeakers are not from the sames series
RT12
http://www.polkaudio.com/homeaudio/products/rt12/

RTi10
http://www.polkaudio.com/homeaudio/products/individual/floorstanding/rti10/

The RTi's are the more suited as fronts and to go with the centre speaker, I think. I was thinking about getting a seperate amp or two to add some juice, but acoustics first.

 

[gullfo]

one thought - if you could enclose the alcove and the stair well with walls and a set of French doors. it would change the ratio of the room, cut down on noise in or out, and reinforce the back speakers so the volume levels were more consistent.

 

[Apedemak21]

"if you could enclose the alcove and the stair well with walls and a set of French doors"

I have thought about framing in a wall to close off the stairs the four more feet or so. I don't think doors will work, this is a basement which apparently I forgot to mention. The areas that you recommended enclosing do worry me as how they will affect sound especially since both of the side surround speakers will be placed with nothing but these areas behind them.


On acoustics, I have formulated a general plan. Thanks a bunch for the advice so far.

What I am thinking of doing of as now is:

-side walls find 1st reflection points and add 2" thick(fibreboard thickness) absorbing panels, I 'm thinking 2 on each wall to cover all the seating positions
-rear wall add two bookshelves centred by two 4" thick absorbing panels with the rear speakers situated between the absorbent and diffuse structures. My innacurate drawing doesn't show, but there is enough room to place a book shelf on one side of the door and then a panel on one door, another panel on the wall next to that then another bookshelf beside that.
-front wall 2" panel behind the two front speakers
-front corners each with full height bass absorbers of the wedge type

 

[bpape]

On acoustics, I have formulated a general plan. Thanks a bunch for the advice so far.

What I am thinking of doing of as now is:

-side walls find 1st reflection points and add 2" thick(fibreboard thickness) absorbing panels, I 'm thinking 2 on each wall to cover all the seating positions
-rear wall add two bookshelves centred by two 4" thick absorbing panels with the rear speakers situated between the absorbent and diffuse structures. My innacurate drawing doesn't show, but there is enough room to place a book shelf on one side of the door and then a panel on one door, another panel on the wall next to that then another bookshelf beside that.
-front wall 2" panel behind the two front speakers
-front corners each with full height bass absorbers of the wedge type

That's an excellent plan. Make the rear absorber at least the width of the seating. You may also want to play with sub location being more along the front wall but not in a corner.

Bryan