Acoustical Treatments Master Thread - Page 244

Originally Posted by scl23enn4m3

Thanks for the reply Nathan. So you're thinking just a big box stuffed with fiberglass would be a good way to go? It's a small room...11'W x 16.5'L with 2' of the length taken up by the false wall, plus the nook. Oh and the kicker is the height is 6'2". Here is view from above that I SketchUp-ed up a while back:

The false wall will be completely AT, screen and fabric.

And the 2" foam on the screen wall has been written in pencil. I'd love some advice on what to do with that as well. Thanks again!

Originally Posted by nezff

I think im going with some 2x4x2 panels on the angled ceilings, lower walls, and some 2x2x4 bass traps in the front wall corners. 5 2x4x2 panels on each side of the angled ceiling, 5-6 2x4x4 panels on each side of the lower walls. Bass traps on that short corner behind the front speakers and subs. Not sure exactly what to do with the front wall that will still aesthetically pleasing.

any advice?

Originally Posted by nezff

No, this would pretty take care of most of the walls and angled ceiling. But will be doing the mirror test.

Originally Posted by nathan_h

That test will be interesting. I'd be worried covering everything.

Originally Posted by nathan_h


That nook looks like a great equipment space....

At the very least i'd go with fiberglass instead of foam. The other concern is that I'd be worried that's too much coverage. I'd mix it up with more diffusion that absorption and focus the absorption on places a mirror test indicates.

Originally Posted by scl23enn4m3


I do have plans to place abortive panels where the mirror test/my calculations indicate. I can continue with those panels on my back wall too if you think that's best. I already have enough to do that and it saves me from purchasing the foam. I'm trying to make any panel I make removable. So if I were to make a frame the height and width of the nook, flush to the rest of the wall, how deep should I go? Do I need to treat the back corners of the nook?

Originally Posted by nathan_h

Dipole surrounds were really important in the early home cinema days when surround mixes had mono surround channels and/or were the movie theater mixes. The fudging around that dipoles introduced indeed created an envelopement that helped obfuscate the negatives of the technology and process at the time (early 1990s).

These days, surround mixes have separate discrete (dare I say "stereo") channels, are often mixed and/or equalized for the home video release, and sound most like what the mixer heard when reproduced using direct radiating speakers in a well set up room.

Originally Posted by nezff

Not sure exactly what to do with the front wall that will still aesthetically pleasing.

Originally Posted by scl23enn4m3

Vault door it is. So would the pink stuff be enough? Or do I have to go with something like OC705? And thanks for the information about the front and rear walls. I didn't know the mirror test applied to them too. It does make sense though, so I'll probably just go that route.

I just realize I didn't address the equipment space idea. My equipment is going to be in another room completely. Plus I won't have access to the nook after the screen goes up.

Originally Posted by vinyl

The nook should remain open to collect the LF - one option similar to treating an open closet is to use several bales of mineral wool stacked floor to ceiling - leaving the bales rolled up in their original plastic wrappers - the nook now becomes one huge trap while still been accessible for whatever.

Originally Posted by longshorejl

Can a bass trap be created behind drywall?

Originally Posted by Johnnycloud

Does it make a big difference if I just set my bass trap up vertically with the base of the trap on the floor in the corners, as opposed to hanging them up in the corner at the mid-wall point?

Originally Posted by Johnnycloud

Does it make a big difference if I just set my bass trap up vertically with the base of the trap on the floor in the corners, as opposed to hanging them up in the corner at the mid-wall point?

Originally Posted by Brad Horstkotte

It will be a bit more effective if it hits the tri corners - how much, hard to say - if you can't or just don't want to, you can make up for it with additional bass trapping elsewhere.

Originally Posted by studlygoorite

Hey people,

So I just finished my Theater Room and got rid of my two Paradigm 15" Servo Subs and bought a Paradigm Sub 2 to try and acheive better bass. I had things going pretty good until last night, my sump pump broke down during this huge rain storm and my whole basement flooded. The insurance guys are here now sucking up all the water and ripping all the wall to wall carpet out. My question is, should I put a sub floor in to help with bass as the floor is concrete or just go with thick under pad a carpet again? I have read that some say the concrete is good for the bass and also that it is bad and that a sub floor should help. If I do put a sub floor in it can only be 1" thick as the ceiling is not that high to beging with. So what are your guys thoughts, I have to decide by Monday?

Thanks, John

Originally Posted by nathan_h

I went with a thin, modest subfloor over my concrete slab, but this was because I wanted hardwood and area rugs on top. The subfloor allowed a little space for air flow and to keep the hardwood from being too firm (a little spring to it).

I'm not sure what I'd do if I was doing wall to wall carpeting -- but I'd be tempted to skip the subfloor except from a moisture/warmth/insulation standpoint.

I can't speak to the acoustics of one scenario versus the other.

Originally Posted by jcthornton

After reading through all the pages on this thread, I have a few questions and a few conclusions

Conclusions
1. I spent too much time doing that how many hours did it take you?
2. Closing/locking this thread and starting a new one (maybe with the best posts summarized at the start) would be a good thing (and restarting every 100 pages after that) 100% agree, I bet many individual avs members have bookmarked pages, we could even have a "Postyour favorite pages" poll to gather that
3. I have huge respect for the many pros (and a lot of the dedicated amateurs) who contribute here Agreed

Question
Being at the earliest part of the planning phase (i.e. early education and knowing too many WAF items are in the way of the theater to do it for at least a year) I am trying to educate myself so I can do a full plan up front. Based on couple of items in the intended theater room, I will likely have the space to do some massive superchunk traps. I am contemplating putting in the plans some 4' face traps in each of the front corners.

I would build that by cutting the 2'x4' sheets into 3 pieces - 2 24"x24" [34" face] triangles and 1 34x34 [48" face] triangle. Then alternate layers of the 48" face triangles [face out] with a layer of 2 34" face triangles [face to walls]. That would give me a consistent, fully-filled depth for the superchunk trap. I am assuming that 2 pieces per alternating layer will not impact the effectiveness of the trap.

If I have the math right, 1100/ f = wavelength (l) [in feet]. And these traps are most effective at 1/4 wavelength or deeper. So, if 1/4 l = 2' then f = 1100/8 = 138hz. With less effectiveness as the frequency drops. But we can have some usefulness as low as 1/10 the wavelength [1/10 l = 2'; f = 55 hz] and possibly lower due to edge effects?

Is my understanding and math correct? For a typical ~2500 cubic foot dry-walled rectangular room, this is all a good thing [in addition to more specific treatment as needed for SBIR, early (first) reflections, and slap/flutter echo, comb filtering, etc.]

I am really asking because I have not seen anybody mention doing chunks this big. Conceptually, I cannot think of a reason why this would not be worth doing, it is just an assumption that most people do not have the ability to devote the space for these (only 0.5*3x3x9 = 40 cubic feet each)