Corner Bass Trap Design

[fredk]

From what I have read here, bass traps need to be 2" thick and if they are positioned off the wall, they will absorb additional sound waves that bounce off the wall.

Yet I see that corner traps are solid. Is there an advantage to having all that extra material so that some areas are much thicker than 2" or is this just a convenient way of making them?

My dilemma is that I have only the wall/ceiling corners to work with and on one of them I will have to work around a curtain.

If there is no advantage to filling the whole corner, it will be a lot easier to build a trap that is 2" hung diagonally across and just in front of the top part of the curtain than having to notch out part of the trap to work around the curtain.

Hmm... I suppose I could just shift the whole trap forward 3-4" so that it is in front of the curtain leaving a 3-4" gap between the back of the trap and the wall for the area above the top of the curtain.

Any suggestions/ideas would be appreciated.

 

[mike c]

actually, the only reason people will space the 2" is to make the panel more efficient at absorbing bass.

but it basically works like this in order of efficiency:
2" panel no space from the wall
2" panel with 2" space from the wall
4" panel no space from the wall

so, if you can make the panel thicker, the better, and if you can fill up the corner, the better as well.

 

[fredk]

Thanks Mike. I am hoping someone can quantify what you wrote. If filling in the entire corner only gets me 5-10% more effectiveness vs. a 4" diagonal trap, then I will probably go with a 4" thick diagonal trap.

I did up a dawing of what I see as my 3 options.

1. full corner trap with an area notched out to fit around the top of the curtain.
2. 4" (or 6...) diagonal
3. full corner trap moved forward (grey+blue area)

Given where this is going, weight and how easy it is to handle is a factor as well.

I havn't chosen curtains yet so I don't know exactly how much clearance I need.

 

[nibhaz]

I'm by far no expert, but I would venture to say that a solid corner trap would be 15-20% more effective. This would probably amount to 1 - 2 sabins per linear foot more, depending on the frequency, with the solid trap.

There are others on the forum that I am sure are much more qualified, and should be able to give a more accurate answer than me.

By the way, great question, I’m looking forward to the responses you get.

 

[mike c]

i would go with the solid corner trap with a notch. i wouldn't think it was only 5-10% or even 15-20% more effective. I'd say at least twice as effective - wild guess on my part, but if you look at the total volume of fiberglass, I'd say it's more than double the 4-6" panel trap.

the corner trap moved forward would be my second choice.

 

[fredk]

Thanks gents. Mike, I hope you're wrong about which one is best and by how much. Its gonna be a pain to notch out 60 some odd pannels!

 

[mike c]

60? i would then recommend the one that is pushed forward

 

[bpape]

4" is a minimum for decent bass absorbtion - gap or not.

What you can do to make your life easier is to just do 4" on the angled face and then stuff with standard fluffy insulation behind. That'll work very well and save you a lot of work and some cash.

Bryan

 

[fredk]

So, solid is much better than 4" diagonal.

I looked at the space again and, from an astetics point of view this is going to be a challenge.

The back wall with the balcony door extends into the dining area (19' total), but I was only planning on extending the trap across the 11' livingroom area.The balcony door covers 6' of that livingroom area.

So:

1. For best effect I need a solid trap.
2. I need to find an estetically pleasing way to end the trap at the dining area.
3. I need a simple way to make a gap for the curtain across the balcony door.

I suspect notching is the simplest way to go for the gap, even if it will be time consuming. I 'only' need to notch 38 tiles.

I also need some sort of light weight frame to attach cloth to that needs to conform to the shape of the trap.

My walls and ceiling are an eggshell white so I will find a cloth that matches that as closely as possible.

Thanks everyone for your help so far.

 

[Weasel9992]

4" is a minimum for decent bass absorbtion - gap or not.

What you can do to make your life easier is to just do 4" on the angled face and then stuff with standard fluffy insulation behind. That'll work very well and save you a lot of work and some cash.

Bryan

What Bryan suggested is the easiest way to go I think. That way there's no "notching" required...just 4" panels with the fluffly stuff behind it. Way easier on the wallet and the eyes.

Frank

 

[fredk]

Maybe I'm not understainding what is meant by standard insulation, but around here its fibreglass, which needs to be contained or I end up with glass fibers all over the place.

I live in an apartment and don't plan on being in one forever, so whatever I do needs to be easily removable as well.

 

[bpape]

If the 4" panels go from ceiling to wall to make the angle, then the standard fiberglass wall insulation IS contained behind it. If you dont' want to use fiberglass, you can use acoustical cotton.

Bryan

 

[jostenmeat]

If the 4" panels go from ceiling to wall to make the angle, then the standard fiberglass wall insulation IS contained behind it. If you dont' want to use fiberglass, you can use acoustical cotton.

Bryan

Bryan,

could you please direct me towards a place with affordable pricing on acoustical cotton? I was once directed to sensible sound solutions, and the prices don't seem to be up right now, but I swear last time I looked, I gawked at exorbitant pricing! (could've made a mistake though)... greatly appreciated...

-jostenmeat

 

[acousticalguru]

Acousical Cotton

Go to Acousticalsurfaces.com direct.

Call them direct for better pricing!!!

 

[Weasel9992]

Go to Acousticalsurface.com direct.

Call them direct for better pricing!!!

Website doesn't work...

Frank

 

[acousticalguru]

sorry

Acousticalsurfaces.com

 

[bpape]

Sensible will be fine (that's me too!)

The higher priced stuff you saw was for a 3lb equivalent cotton to OC703 and yes, it's higher priced. What I'm talking about is the bulk cotton. You don't need the high density for the stuffing in the rear. The thickness will make up for it and you have 4" of 3lb in the front.

Bryan

 

[fredk]

That (cotton) sounds better. I think I have a plan.

Now I need to get the curtains in place. Actually, I need to get the curtains first...

 

[bpape]

Well of course! SWMBO always comes first...

Bryan

 

[jostenmeat]

fredk, I learned that having space was ideal behind the trap, perhaps contrary to what's been said here (?). That the bass waves get attenuated three times before reaching your ears: once thru the trap, a bit of absorption at the actual bare wall, and the third time coming back thru the trap before arrival at the ears.

Just bringing it up for everyone's educational sake...

thanks Bryan. I am looking towards putting cotton on the floor between the white carpet and my dual black Ikea rugs where the center speaker is sitting, angled up. I realize having the center ceiling mounted would be better, but I have my reasons for not going there.

Wouldn't high density be desired here? Also, I think some "high prices" I saw were because the pieces were sold in bulk. Are there any links you can provide me for one or two pieces? Whether here or PM? Thank You!!

(sorry fred for the hijack! hope it works out well )