Hello everyone. I'm a bit confused as to front wall absorbtion. I'm in the process of finishing up a H/T in my basement. The room is done with the exception of carpet, furniture and acoustical treatments. Up until a week ago my front wall was just exposed studs and insulation. I had some leftover drywall so I chose to just screw it on, no tape or mud. This wall wont be seen as i will have a acoustically transparent curtain hiding my speakers and TV.

Being impatient I was forced to bring my equipment in there and fire it up. Like I said, empty room, no carpet. Yeah, it sounded like a huge tiled bathroom filled with clock radios blasting on 10 while not quite tuned to a station. I was the most harsh fatiguing sound I've ever heard. There wasn't any bass to be found in the room aside from one of the corners. Also for the first time I felt the mid punch that the Cornwalls can produce. From 28 feet away it felt like someone was playing a snare directly against my chest. But like I said, only in that one corner. I'll post a pic of the room shape and dimensions later. Obviously, carpet and furniture will have a huge impact on the sound of the room. Also I have 5 bags of Roxul AFB in the garage waiting for installation in various areas.

My question is regarding my subwoofer and front wall treatment. It will be facing towards the front wall so I can pick up a little extra gain. If I put bass traps in the corners and along the wall/ceiling and wall/floor wont it kill the gain from the subwoofer facing in that direction? Similarly, my mains are Klipsch Cornwall II's and Klipsch Hereseys. The Cornwalls have excellent bass output. I really don't want to kill it with trapping. Also, I'm thinking I should remove the drywall from the front wall. It won't be seen and it seems it would be free mid and high absorption.

What do you guys think?
Mike

Here is a rough drawing of the room. The red arrows near the pellet stove indicate areas where it would be possible to remove the drywall and cover it with a panel of some sort. Would this be advantageous in any way. Would it get rid of the irregularly shaped room factor?

You wont 'kill' the bass from your speakers by adding traps - you will actually get more, deeper (apparently) and better controlled output from them. As you say carpet, furnishings etc will help with mid / high - but you dont want to go to far with getting rid of all that or your room will sound weird!
Front wall has been covered well here and actually needs very little done to it probably. My gut feeling is that removing the drywall and getting a room that is evenly sized would be very beneficial. It is unusual to be able to make a room bigger - but usually very easy to make it smaller... There is so much to read on this forum it takes an age, but very worthwhile. I spent weeks on studying it. It has paid off handsomely!

I guess that's a bonus of building a room in a basement. If a can cover up the areas where the drywall was removed with a fabric covered frame it wont look unsightly from the inside of the room and the outside wont look any different. It will expose more fiberglass insulation to act as an absorber and the sound energy that goes beyond that will get diffused by the rest of the "junk" in the basement. I'll wait til a few more people chime in before I go cutting any holes though!

As far as the drywall on the front wall, I'm going to remove that now. Had no intentions of having it there to begin with but I had a few sheets of drywall left over and they were getting in the way. Hastily made error on my part.

The drywall on the front wall has been removed. It made a HUGE difference. There's R-19 insulation, an 8 mil plastic vapor barrier, a 3" air gap and then the concrete wall now. Even the sub sounds better though there is still little bass at the listening position. I'm really surprised at the difference in sound overall. It was definitely a step in the right direction.

Still wondering about the bass trapping with the sub firing towards the wall. The sub is a dual 15" ported box if that makes a difference.

Here's my take on that:

Front Wall Absorption

The front wall is as good as any other surface to reduce overall ambience, but once the rest of the room is treated properly the front wall becomes less important.


That's not necessary and probably not a good idea. At low frequencies all speakers radiate omnidirectionally anyway. So you should orient the sub as the manufacturer recommends. Here's my take on that too:

Subwoofer Placement

--Ethan

Thanks guys. Unfortunately, due to the size of my mains and sub, the only option I have is keeping it somewhat centered to my front wall. It's far to large to put in the room somewhere. Thats part of the reason why everything is behind the AT curtain. Function will have to follow form in this case.

I'll plan on treating the front wall at least with bass traps. Like I said previously the drywall has been removed and I'm hoping the exposed insulation will suffice for the mids and highs.