Need advice on room setup

[Dr. Videophile]

I have a bonus room where I want to install a home theater. The side walls are trapezoid-shaped and I want some advice on how this might affect acoustics, etc. I am in no way an expert on acoustics, but I do want the best compromise between form and function. Basically I want a "built-in" look. I designed this setup based on visual aesthetics only. There is not a large enough flat surface to mount a large TV, so I designed the unit shown in the pics.

I haven't picked out the actual components that I will use yet. The attached pics are based on a random 65" plasma I found on a retail website. The rest of the pictured components are the one I have on my existing (low-budget) system. The unit will be framed out with drywall and painted to match the room. I will have a remote repeater system so the cabinet doors can remain closed during operation. My main concerns are:

1. Acoustics - by "building forward" a wall in the center of the existing wall, two recess are created. do these recesses create any potential for echo or some other unwanted acoustic effect? If so, how can I fix it?

2. Ventilation - I thought about installing a pair of fans on either side, one blowing in and the other out, to create a "blow-by" current. The cabinet as designed has large holes cut for cables and ventilation; I thought about adding holes on the side that would extend to the exterior surface of the unit for the fans.

3. Subwoofer placement - the most aesthetically pleasing place would be to have the subwoofer surface mounted in the right-hand side of the unit. In the pictures you will notice a door for access to the cavity in the back. I could put the sub underneath this door and cut the interior cabinet around it. The other idea I had was to put it inside the front cabinet in the middle section (the empty section in the picture). I would then have to make the cabinet doors shorter so the middle section is exposed even with the doors shut.

4. Front and surround speaker placement - I thought I would just mount them on the slanted part of the ceiling. I read somewhere that the speakers should be mounted at the same height as the center speaker, which I have chose to place above the TV. With the size and shape of the room (the floor is 19.5' x 21'), would I benefit from a 7.1 system over a 5.1?

Attached are renderings of my idea. There is a computer desk in the back right-hand corner of the room and the furniture is how I currently have it arranged. I do not plan for this to be an extremely expensive setup. I am willing to pay what it takes, but I will be buying the components one at a time as the money comes in. It will probably take me a while to do this.

[Dr. Videophile]

I thought I would show a rendering of the two possibilities I came up with for the subwoofer placement. It would be more hidden using the first way, but I want the best sound possible. I suppose I could do something different altogether like putting it in the back of the room or a corner. I'm open to suggestions.

[rickcreel]

Hmmmmm...... You ask an awful lot to be considered here. However, let me make a few suggestions:

The ceiling shape is fine and actually helpful. However, if you're wanting to contol some audio anomolies, think of putting some acoustic treatments on the side walls. You can make these yourself. Use about a 4X2 panel, approx. 2" thick, filled with rockwool. Place these on either side of the room, about 4 - 6 feet from your speakers. They should be about 2.5feet off the floor to the bottom edge.

Next, have two more of these panels at the very back of the room, about 3 feet in from either side. This is a basic minimum and is used to reduce "reflections".

About speaker placement, the center channel will be fine. However, try to find a way to direct the speaker down to the front row. This way you won't loose the quaility of sound that comes from the center of the cone. The left and right speaker should be lowered to achieve the same thing. They should also be as close to either side of your screen as possible. Otherwise, your sound coming from the front will be too wide. Since you are having to build the cabinet anyway, try to find a way to incorporate the left and right speakers into the cabinet, on the center level of the screen.


Your side speakers, again, should be at about the level you are sitting at for your ears. However, your furniture should not be against the walls, next to the speakers.
If you can afford a 7.1 or 7.2 system, this will be your rear speakers. Again, check the height of your placement. Remember, you will be sitting down in your room. The audio coming from the center of the cones is the best. If the cones are to high, are over your head, you will loose much of the response from those speakers.

Subs are non-directional. You can place the sub nearly anywhere up front. Of course, if you use a good sub, you will want it to face toward you. This will assist some in the "pressurization" from the sub. You will need all doors and windows closed to get the maximum effect from your audio.

Also, for either a 7.1/2 or 5.1/2 system, you will need a good processor. Otherwise, you've just wasted your money. The big box stores will not be able to help you much here. You need to go to a true audio professional. It will cost more, but you will be happier with the end result.

Ventilation: I don't see that you're going to need fans. You're not going to have that much equipment in there. Just be cautious about "stacking" equipment. Leave the back open if possible. If not, maybe a 4 inch gap at the top of the bottom shelf along the back. This won't be seen unless you're crawling on the floor.

I hope some of this helped. You can visit our official site at www.advancedaudiovideo.com for more ideas on planning and building a home theater. There's plenty of pages there with information to help you .

[lararefaeli]

Hello Dr. Videophile......
Firstly thanks for the nice post and recently I completed the setup of Acoustics and Audio system into my drawing room.Well I am totally agree with you and I think that for better outputs from audio system the acoustics should be properly managed.Distortion and reflection should not produced into the room.Thanks for the post.

[rickcreel]

I am with Advanced Audio Video, LLC. Our web site at www.advancedaudiovideo.com has more on how to control acoustics in a room. We do auditoriums, home theaters, etc, and have a background in acoustics. In fact, we have THX certification in our model theater. We've done large commercial theaters for Disney and others, as well as home theaters. Audio is very important, but audio is no good if the room is not properly treated. Visit our web site for more information on treating a room.