Thoughts on trap concept?

[Gonny]

Hello everyone. First time poster here. Thanks to all who've shared your knowledge - I've learned a great deal poking around in recent months.

I am a hobbyist building a room for personal use, converting an existing space in a basement. As is typical of home rooms, it is small and boxy. Total space is 17'9" X 11'3", with 7' ceilings (ouch!). Under the circumstances, I understand that I probably can't get too much trapping. Given a feature of the existing space, I have a bass trap concept and am wondering if it is something I should think about more.

Here are pics of the room as it currently stands. I plan on moving everything out and finishing the space soon, so starting to think ahead to some acoustic treatment.

studio 1.jpg

studio 2.jpg

At one end of the room, there is a closet that goes the width of the room (see second photo, above). Right now, the bi-fold closet doors are not installed, but I had planned to install them, for a finished space of 14'3" X 11'3" (when the closest doors are closed). On each side of the closet opening are walls that frame in the closet (with the sconce lights on them). It seems to me I could remove the drywall from both sides of these walls (so they would just be open stud frames), cover the front with a light wood frame and fabric facing, and fill the wall with rockwool. The rockwool could be made quite thick working back from the front of the wall (all the way to the back wall?). I am sure I could move the electrical around to accommodate whatever I do.

Here is a pic of the back side of one of the walls. It's 3'1" from the back side of this wall to the back wall. The drywall is only screwed on at this point as I got in there to do the electrical.

studio 3.jpg

What I am wondering is whether it would make sense to effectively use the the framing of the walls on either side of the closet opening as frames for bass traps. I'd be happy to provide more pictures, drawings or other info that might be helpful. Mostly I am wondering whether this is a concept worth further consideration.

Thanks in advance for your consideration.

-John

[Paulus87]

Hello everyone. First time poster here. Thanks to all who've shared your knowledge - I've learned a great deal poking around in recent months.

I am a hobbyist building a room for personal use, converting an existing space in a basement. As is typical of home rooms, it is small and boxy. Total space is 17'9" X 11'3", with 7' ceilings (ouch!). Under the circumstances, I understand that I probably can't get too much trapping. Given a feature of the existing space, I have a bass trap concept and am wondering if it is something I should think about more.

Here are pics of the room as it currently stands. I plan on moving everything out and finishing the space soon, so starting to think ahead to some acoustic treatment.

studio 1.jpg

studio 2.jpg

At one end of the room, there is a closet that goes the width of the room (see second photo, above). Right now, the bi-fold closet doors are not installed, but I had planned to install them, for a finished space of 14'3" X 11'3" (when the closest doors are closed). On each side of the closet opening are walls that frame in the closet (with the sconce lights on them). It seems to me I could remove the drywall from both sides of these walls (so they would just be open stud frames), cover the front with a light wood frame and fabric facing, and fill the wall with rockwool. The rockwool could be made quite thick working back from the front of the wall (all the way to the back wall?). I am sure I could move the electrical around to accommodate whatever I do.

Here is a pic of the back side of one of the walls. It's 3'1" from the back side of this wall to the back wall. The drywall is only screwed on at this point as I got in there to do the electrical.

studio 3.jpg

What I am wondering is whether it would make sense to effectively use the the framing of the walls on either side of the closet opening as frames for bass traps. I'd be happy to provide more pictures, drawings or other info that might be helpful. Mostly I am wondering whether this is a concept worth further consideration.

Thanks in advance for your consideration.

-John

It would work great, but instead of filling the entire area with rock wool - use Wideband absorbers, or commonly known round these parts as "hangers". Line the closet with 2" of rockwool or similar on the back, sides, floor and ceiling, then use sheets of 3/4" plywood or chipboard with a bitumen dead sheet on one side, then the entire panel wrapped in insulation (the insulation type is not super important, but around 2" 60kg/m3 works well) then hang the panels on chains, angled at 45 degrees with the leading edge pointing towards the listening position. The panels should hang with about 4" between them and completely hanging freely. Hide the panels behind lightweight wood framing with stretched fabric.

More here:

https://www.researchgate.net/publicatio ... d_Analysis

[Gonny]

Hi Paul, and thank you very much for the response. You read between the lines and answered my real question, which was "is there an opportunity here?"

The hanger idea looks good. I haven't read the paper yet, but will (hoping enough of that calculus from decades ago will come back to me ). I will read what else I can find around these parts on hangers to help me in my quest, but thanks for pointing me in this direction.

If you don't mind, a couple of questions before I wander off and do more research. First, you mention a bitumen dead sheet attached to the plywood/chip board. A quick search suggests it's a roofing product. Am I on the right track here?

Second, I am wondering how important symmetry is. There are two reasons I am asking. First, the left side wall is 5 inches wider than the right (3'10" vs. 3'5"). The second is that there is a boxed in HVAC pipe inside the closet on the right side that I would have to work around. It is evident in the second picture in my original post, but here's a different look from inside the closet:

studio 4.jpg

Its face is not parallel to the wall behind it. It is about 22" deep at the side wall, but only 17" deep where the closet opening starts (17" "high" all the way across). Apologies for failing to mention this in my initial post.

I can't imagine that for my purposes the lack of symmetry would be a big issue, but that's my gut (and wishful thinking) talking, not my head.

Thanks,
John

[Paulus87]

Hi Paul, and thank you very much for the response. You read between the lines and answered my real question, which was "is there an opportunity here?"

The hanger idea looks good. I haven't read the paper yet, but will (hoping enough of that calculus from decades ago will come back to me ). I will read what else I can find around these parts on hangers to help me in my quest, but thanks for pointing me in this direction.

If you don't mind, a couple of questions before I wander off and do more research. First, you mention a bitumen dead sheet attached to the plywood/chip board. A quick search suggests it's a roofing product. Am I on the right track here?

Second, I am wondering how important symmetry is. There are two reasons I am asking. First, the left side wall is 5 inches wider than the right (3'10" vs. 3'5"). The second is that there is a boxed in HVAC pipe inside the closet on the right side that I would have to work around. It is evident in the second picture in my original post, but here's a different look from inside the closet:

studio 4.jpg

Its face is not parallel to the wall behind it. It is about 22" deep at the side wall, but only 17" deep where the closet opening starts (17" "high" all the way across). Apologies for failing to mention this in my initial post.

I can't imagine that for my purposes the lack of symmetry would be a big issue, but that's my gut (and wishful thinking) talking, not my head.

Thanks,
John

Yes a roofing product, but not the one with the little minerals on the surface. The sand coated one is okay, or the completely smooth one. Danosa do a nice product.

Regarding symmetry etc, not a big deal. Just cut the hangers to fit. With the 45 degree angle you should have enough space not to have to cut the sheets down the width, so just adjust the height to fit. Where the bulkhead is, just fit the hangers below it.

[DanDan]

I don't have the links but I have seen some impressive results from hangers here. Our good friend Boggy, sadly RIP, achieved certified pro results in many studio builds. In deference to his part of the world he specifically used simple locally available materials. Light wood framing holding 60cm light fibre batts in place. Worth a look at his build pictures on Instagram and FaceCloth........ bogic petrovic. LF symmetry is a questionable concept, particularly behind. Don't sweat it. When building a big or deep intrusion into the room you might consider incorporating a quiet box for computers and other fan cooled gear. Also a cubby hole to contain a guitar or bass amp.

[Gonny]

Thank you both, Paul and DanDan. Great info to get me started. Looks like I've got some research and thinking to do. I will check back in at some point and update on where I wind up with this, but between self-imposed pandemic restrictions (making materials procurement a bit trickier than usual for the moment) and my own deliberate but casual pace, I don't expect that will be real soon.

[DanDan]

Yea, the 2Do List. Mine has gotten longer during the Panny! Deep fibre only traps are best done with the lightest cheapest fibre. Attic Insulation.

[Gonny]

Hey DanDan - just want to make sure I understand your last post. Are you saying if I went with what I originally presented, light attic insulation would be preferred over rockwool? Makes sense.

I am going to look into the hanger idea more - it sounds intriguing. Later this month I am taking some time off and finishing/painting the room. Opening up those walls and doing the hanger thing is something I can easily retrofit, so probably a winter project.