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Discussion Starter · #1 ·
I'm building some corner bass traps from 703, cut into wedges for a "superchunk" style trap. For WAF purposes it will only be a four foot stack of wedges capped with an oak corner shelf.

For WAF purposes it will also be up off the floor above the baseboard (the bottom will be about 6 inches from the floor). I realize I'm missing that floor/corner intersection point, but the bottom of the trap will be open (wedges sitting on 2X2's screwed to the wall) so I'm hoping that will catch some of the corner waves.

Will I lose much performance having it elevated above the corner?
 

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SOunds like you're doing as much as you can to stay within the parameters you have to work with. On the floor would be better but 6" isn't bad.

Bryan
 

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Discussion Starter · #3 ·
Thanks Bryan. Maybe once she gets used to it in the corner I can wrap a few more wedges in burlap and just shove them under the trap so they can be easily removed if needed...
 

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Discussion Starter · #4 ·
Speaking of extra wedges - would it help if I stuck a 3-wedge stack in the four upper wall/ceiling corners of the room? These would each be a six-inch wedge of 703 with a 24 inch wide face. Just wondering if it is too little to have any effect.
 

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Speaking of extra wedges - would it help if I stuck a 3-wedge stack in the four upper wall/ceiling corners of the room? These would each be a six-inch wedge of 703 with a 24 inch wide face. Just wondering if it is too little to have any effect.
**** yes that would help..

Glenn
 
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I'm building some corner bass traps from 703, cut into wedges for a "superchunk" style trap. For WAF purposes it will only be a four foot stack of wedges capped with an oak corner shelf.
Do you absolutely NEED the shelf on top? To be honest, you are better to leave the absorption surface exposed at the top of the trap, rather than covering it up with something that is not acoustically transparent.

It is not *only* thickness and mass that affects how much absorption you will get, but also the amount of actual absorption material that is exposed to the room.

You do need a certain amount of mass and thickness to deal with the lower frequencies, but after a point you want to aim for a greater amount of exposed surface.

TBH, I'm not entirely sure that a gap of few inches below the trap is going to give you less performance. It may actually give you more, because it gives you a little extra exposed absorption surface. But I'm only guessing on this point, as I haven't had a chance to test the differences with this particular trap design.

And I'll add my vote as well for putting some traps in the upper corners as you suggest. That will definitely offer you some benefit -- again, preferably keeping as much of the absorption surface exposed as possible, rather than covering it with wood. I think if you were to put the wood on one surface of a smaller trap like that it would have a particularly detrimental effect (more so than with a larger trap, because you get an even smaller ratio of exposed surface to covered surface on the small trap). Further, you end up creating additional corners when you put wooden end caps on these traps! Better to be absorbing from as many directions as possible, rather than just focusing on absorbing in the horizontal directions!

Better yet would be to treat the whole corner from floor to ceiling with a superchunk-type trap . . . and it might even look nicer to do it that way than having a break in the middle, with a big trap on the bottom and then another trap on top. If you build it right and use a covering fabric that matches closely with the colour of the walls, it may actually be less noticeable as being an "object", and my look more like a natural part of the room design.

Perhaps, if you have room, you could throw some plants on stands, or a small indoor tree, in front of the traps. Or you could put some kind of lattice with a climbing vine-type plant across the front of the trap (though it's best to keep a lattice as light/sparse as possible, rather than having wider wooden slats across the face of the trap). Just a few possible ideas for accomodating WAF while maximising the amount of acoustic treatment you can install into your room ;)
 

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Discussion Starter · #8 ·
Thanks for the ideas Scott. The wife wasn't too crazy about the floor to ceiling idea, and liked the idea of a shelf which is how I ended up with my plan. I hadn't actually talked to her about the extra chunks in the upper corners....I thought that might be something I could squeeze in later, but your right about one large color-matched column blending in better. Of course that would cost me another case of 703....

If I do go with the shelf, what if I leave a gap between the top of the fiberglass and the bottom of the shelf (the gap will be covered with burlap like the rest of the front anyway)?
 
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I thought that might be something I could squeeze in later, but your right about one large color-matched column blending in better. Of course that would cost me another case of 703....
It would be well worth it, though, for the additional improvement you'd get.

If I do go with the shelf, what if I leave a gap between the top of the fiberglass and the bottom of the shelf (the gap will be covered with burlap like the rest of the front anyway)?
Tough to say for sure, as with the difference between gap/no gap at the bottom.

Is the plan to actually put something on the shelf, or is it just supposed to look like a shelf that you *could* put something on?

If you MUST put the end cap/shelf on there, you might consider cutting a series of parallel slits in the shelf, preferably at least 1/2" to 1" wide, so that all but the outer inch or so of the triangle ends up being like a grid of sorts, so it will let sound pass through it. You want the slits to be big enough to easily let through a decent amount of sound pressure, but obviously not so big that something would fall through if you set something on it.

From there, I'd say it's better if you don't put anything on the shelf, though you could probably put something relatively small on the shelf, or something that doesn't significantly impede the openings. Or you could hang a small plant or some kind of sconce or whatever above it. Main thing is to try to keep it as open as possible.

Another idea, if you don't want to see the slits in the shelf, is to make an appropriately sized triangular fabric "place mat" to put on the shelf. And perhaps, if you are going to put something like a potted plant or something on the shelf, you might put the plant on a small stand of sorts, to leave a little breathing space between the bottom of the pot and the shelf.

Maybe you'll have a few better ideas of your own.

I'll add a (very) quick and dirty sketch here so you can get an idea what I'm talking about.
 

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I was kind of thinking the same thing. If you have a scroll saw and are handy (or want to hire it out to a woodworker looking for a fun project), you could potentially make the top shelf a decorative thing. Think about the old scrolled woodwork on speaker fronts, or a floor HVAC grille.

Maybe something like this:

http://www.signaturehardware.com/product3040?tr=sh&Prod=144307

with a cloth backing on it? Wouldn't have to be quite so intricate but you get the idea. You could even do a school logo, your monogram initial, etc.

Bryan
 
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That's a cool suggestion too, Bryan. :cool: Surely one could come up with a design to fit just about any decor.

On another subject, I've been meaning to point out:

I am serious... and don't call my Shirley.
I hate to break it to you, but your Shirley's actually the one who's been calling ME! ;) :bigsmile:
 

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Discussion Starter · #12 ·
Those are some great ideas guys! I'm pushing my limited wordworking skills just making the frames for the fabric covers, but the slatted or scrolled shelves would look really nice.

I might just hold off on the shelf for now and cap it with a burlap covered wood frame like the front. This would leave it open to sound on top and I can always add a slatted or scrolled shelf later OR remove the cap and continue the stack to the ceiling at some point in the future.
 

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Doh! I need to go change that - thanks Scott.

Bryan
 

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I owe you a beer at RMAF this year :coffee:

Bryan
 
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Would that corner trap be better or worse with the back of the trap open with fabric covering it only, or with plywood covering the back?

Thanks
 

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Ethan,

I'm not sure if vfrjim is referring to panels or superchunks but to clarify, when you say straddling, that refers to panels. Since the edges of superchunks are against the wall, it should be ok to back them with plywood, correct? My apologies if this was obvious to everyone.

Bob
 

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If you're doing triangular chunks and it is going to fit right into the corner then a hard backer wouldn't be a problem.

Bryan
 
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