The idea is that I will only drywall the ceiling, and the top 4ft of the sides and rear wall. The entire front wall will be 2" of linacoustic, over a 2x4 frame that is stuffed with R13 on top of a sheet of plywood against a poured concrete outer wall. The side and rear walls will have the bottom 4' covered with 1" of linacoustic over the 2x4 frame filled with R13.

The thought is that without the drywall on the bottom and front, it will create much better absorption to lower frequencies, and also create some interesting variety in the room dimensions as far as modes and reflections are concerned.



additional info for my particular situation for those who are wondering...

I am finishing the basement of my townhome into a theater. It is above ground. I am not really concerned with sound getting into the room as it is a pretty quiet area in the suburbs. I'm also not too concerned with sound getting out, especially in the basement of my own home since its only this room and a garage down there. There is still a 5ft+ gap, few layers of drywall, poured concrete and double firewall/sound insulation between this room and the next unit, and I think the subwoofer is the only concern I could have, and one sheet of drywall isnt going to help with that.


I have posted this idea in a couple other threads, but wanted to call attention to it specifically just in case I'm making a big mistake as the drywall is going up as I type this.

bigtourist,

I understand what your are trying to do acoustically, but one comment (as i also considered leaving the drywall off my backwall for absprption purposes).

As was pointed out to me >> You may be getting into trouble with a code situation - leaving a wall open in a "habital space" with no drywall could be a NO-NO...? You might want to check into the "code" aspect of your idea.

Are you concerned at all about trying to keep the theater sound from transmitting to other parts of the house? If so, it would probably be best to drywall the entire inside of the room.

The idea is that I will only drywall the ceiling, and the top 4ft of the sides and rear wall. The entire front wall will be 2" of linacoustic, over a 2x4 frame that is stuffed with R13 on top of a sheet of plywood against a poured concrete outer wall. The side and rear walls will have the bottom 4' covered with 1" of linacoustic over the 2x4 frame filled with R13.

The thought is that without the drywall on the bottom and front, it will create much better absorption to lower frequencies, and also create some interesting variety in the room dimensions as far as modes and reflections are concerned.

additional info for my particular situation for those who are wondering...

I am finishing the basement of my townhome into a theater. It is above ground. I am not really concerned with sound getting into the room as it is a pretty quiet area in the suburbs. I'm also not too concerned with sound getting out, especially in the basement of my own home since its only this room and a garage down there. There is still a 5ft+ gap, few layers of drywall, poured concrete and double firewall/sound insulation between this room and the next unit, and I think the subwoofer is the only concern I could have, and one sheet of drywall isnt going to help with that.

I have posted this idea in a couple other threads, but wanted to call attention to it specifically just in case I'm making a big mistake as the drywall is going up as I type this.

What you're planning won't be super effective from a bass trapping standpoint, though it would work to soften the room up some in the high mids and highs. You'd probably be better of just finishing the walls with sheet rock then adding treatment after the fact both from an acoustic and a code standpoint.

Frank

i just checked with some people about code, and they said not to worry about it. apparently a local contractor built his entire theater with no drywall at all. i know that doesnt mean its legal, but i can always throw up some drywall on the bottom if it really becomes an issue.

as i mentioned above, im not too concerned about sound getting out/in to the room.

my roommate and a friend are hanging the drywall now and im sure part of their push to keep on the plan is so they dont have to go pick more drywall up at lowes :)

i suppose we'll consider this an experiment. lets wait and see how the rew results turn out in a couple months! i do plan on first reflection & bass trap treatments using 2" oc703.

Are you concerned at all about trying to keep the theater sound from transmitting to other parts of the house? If so, it would probably be best to drywall the entire inside of the room.

I second that motion....5/8" Drywall all over the room and ceiling, and at minimum R-13 insulation on walls and R-19 insulation in ceiling. If you're gonna build a room, go all the way. There are many other ways to acoustically treat the room post-drywall.