Mini bass traps

[stainless]

I call these "mini" because it's not the usual 24" x 48" piece of 4" compressed fiberglass set at a 45 ° in the corner. I did ask (both here and at Sayers forum) if there was a specific reason fro 24" (aside from being conviently the same size as the panels .... got no replies...

..this may perhaps elicit some comments

Anyway, the area treated is in a corner above my desk/console. While I had enough room to place a full panel diagonally... I didn't reall want to give up the room.

So I chose to build a solid ~ 12 x 12 x 16" (diagonal) trap. I took a full sheet of 2" (easier to cut straight) and first cross-cut 12" pieces using an electric carving knife and a simple jig (see below). Then cut the 12 x 24 pieces down to 12 x 12, then cut into diagonals.

Carving knife- Proctor Silex $9.99 at most big box outlets... much simpler than a sharp utility knife and a lot less glass on your extremities!

Jig is a simple base board (in this case a 30" x 22" piece of scrap MDF, a piece of 1 X 3 pine as a 'fence" on one side, a couple of 2" risers on each side, and another piece of 1 x 3 as a cross-fence... all in all took about 10 minutes to make. I drilled a couple of holes in the cross-fence so I could stab 8 penny nails into the rigid panels to hold in place. Set the panel with the exposed area the dimention you want, place the blade of the electric knife against the edges of the jig... and BINGO, a quick and easy cut.

I then ripped a 2 x 3 at a 45° so that both halves were the same, cut a 3/8 x 3/8" dadoo into the back side of the 90° corner to serve as a "trap" for the diagonals. Two of these were attached to the wall opposite each other and parallel/plumb. Then the diagonal pieces were stacked within to the ceiling.

The ripped down diagonal of the 2x3's will be used as a mounting surface for a fabric covered 1" panel (more cosmestic), but this also gives me about a 1" air space between the face pice and the stacked digonals, which is solid and slightly over 8" from the corner stright out.

The cover panels were back-cut ata 45° (more or less) and now my challenge will be to see if I can get the fabric attached without excessive wrinkles.

I plan on treating another corner in the room the same way (this time ceiling to floor). The JBL monitor shown in the pic has the RMC (Room Mode Correction) set-up. Initial response resulted in athe RMC making a deep cut at ~110 Hz. It will be interesting to see if the traps cause this to change

Cieilng corner traps will be the 24 x 48" panel, and then add 1" and 2" diffusers around the room

Isure hope this does something beneficial..... (besides looking neat...)

[roman]

Wouldn't a Helmholz absorber be more efficient? From a completely uneducated standpoint this looks like it might not have enough mass to help much.
So... well. Does it noticeably absorb anything?

[stainless]

Well, my understainding (as crude as it is) seems to indicate 4" of rigid fiberrglass pretty much kills LF.... so I got that much and more

and....beats the crap outta me... I haven't run the JBL thru the rMC again

ask me in a day or two....

[seanmorse]

It does look good - sure hope it does what it should. Fingers crossed.

[gfh]

So how many sheets of 2" do you have packed in that corner? Looks like a pretty cool idea to me.

[stainless]

2 1/3 sheets and it will take 1 1/2 of 1" to cover the front... all in all ~ 18 pounds of rigid FG

and the front/diagonal dimension is 20" so space savings wasn't huge...

try and finish this corner off and maybe get a couple of 'diffusers' hung on the wall on each side

[stainless]

a short update...

applying fabric to the panels

I'm using 3M spray adhesive 45... it's NOT necessary to spray the front of the panel and the back of the cloth.... no forgiveness! spraying just the rigid FG is sufficient

Smaller panels (half) are easier than full (48").... especially if you want the fabric to lay really flat...

Attaching to the wall/ corner frame.... velcro is not real effective... welll maybe if you apply lots of velco.. but it doesn't stick real well to the fabric... I suppose if you had patience (and knew how to use a sewing machine) you could sew it on.....

So now I'll try upholstery washers and drywall screws... (gotta go to the hardware store.... again)

If anybody has a clever idea, let's hear it!

[bodaddy]

Can you tell me how much the fiberglass cost and would it be better to just go to Markertek and buy traps for $20.00 a pop? I do like the Idea you have and the looks possibility though.

[seanmorse]

I'd be surprised if the Markertek cheapies would do as good a job (though I haven't seen their rating). Even if they did, they're only 2 feet tall, so you'd need a couple hundred bucks worth to cover the same area.

[stainless]

I paid $48 a carton for the 2" (they were out of 4 and i didn't want to wait and the cost was pretty much equal), 6 pieces/ carton so each 2 x 4 panel is `$8.00cut into the 12 x 12 x 16 triangles, one sheet will cover 32" of corner compared to the 23.5" of the Aurelex foam, and the aurelex trap/diffuser weighs 2 pounds whereas each sheet of 2" weighs ~8 pounds (or for an equivalent 24" about 6 pounds of mass)
so absorbtion should be much better (3X the mass).

The material is Certainteed Acoustaboard CB-350 and i found it thru a local building supply distributor (not Home Depot). all total with the cost of the 2 x3, the clothe and adhesive an 8' corner would cost me under $40 plus the time to do it.

I never used the Auralex corner trap/diffusersso I don't know know how well they work

Not only do i like to think I'm saving money (which is a silly concept as I just go buy something else! ) but I enjoy (most of the time) the projects I start

[bodaddy]

Like I said, I really like your traps and now plan to build myself some. I did have The markertek traps in my old building and they worked just fine with 2 in each corner but since this project is a little cheaper and I think will look better, I am going with yours. Thanks for the info. I also had 2 Primacoustic packages that were great but the acoustics and a ton of gear went with the sale. Now I'm starting over at home and would rather save my money on acoustics(but still have a working product) and buy more equiptment(I'm a gear junkie)

[mblindsey]

Would two uncut panels, stood floor to ceiling covering the corner, help the sound of a room at all? Or, do you really need all the mass created by the "triangles"? Just wondering if I can get by with a short cut...

[stainless]

I'm by no stretch on anyones imagination an expert on this, so take my comments FWIW

Standing the uncut panels in the corner is the way most folks do it...

which is what sent me to question whether it is the best way to do it, or simply convenient since that's the size the panels come in. It'd certainly be quicker

I would need to glue two 2" panels to get to the recomended 4" thickness, so cost would be ~32 + fabric and fasteners... so about the same material cost... and it would take a bit more space out of the corner and then there's that big air space behind... seems the filled corner will absorb better, but then again it might not be enough to be really advantageous (I'm leaning towards more dense is better)... and if you have un-coordinated musicians, if anyone leans on the panels spanning the corner, it will fold... and it doesn't unfold/uncrush worth a damn... With the solid corner, it's remarkably firm

either way, it's going to be better than an untreated/bare corner

[mblindsey]

excellent points. i'm currently building panels, and now kind of wish i built the corner traps in addition to the panels. oh well...when someone smashes the ones i have in the corner, i'll have an excuse to copy yours.

[tmix]

Stainless,
It is my understanding, when it comes down to bass trap size it is mostly a question of cubic feet.
I mean thickness matters, because it takes thicker panels to trap the bass frequencies but once you get to solid corners like what you did (and me) it is a matter of quantity.
Have you ever seen the Auralex LENRDS?
Small by comparison to what you did!

The air gap behind panels in corners is not as effective as solid absorbant material.

[stainless]

I've looked at them, but pretty pricey corner treatment (although they look nice)

this corner (70") equals right at 3 cubic feet, which , based on the physical dimentions of the LENRDS is roughly equivalent. So
if I extrapolate the Acoustic performace data (which may not be proportionately scientific) to my greatest depth I get 1.45 (NRC increases by 0.05 for each additional 1/2" of thickness), and I didn't include the cover panel.

I was originally going to fill the air gap with a piece of of 1", but after looking at some of the plans for traps on other forums, the air gap seems to come into play with the higher freqs... so I decided to leave it... and OK, it's one less thing to do and some more material to use elsewhere

I've got another corner to treat (ceiling to floor) and then I'll use the same method for some ceiling/wall traps... then I'll run the JBL's RMC again and see how much of a difference it makes at the low end. By no means hard science- but since so much of the 'sound" of music is subjective anyway, I suppose everything is ... well subject to someones opinion

....of course all my dialogue is to try and justify/rationalize my methods/madness and why I bought 32 cubic feet of the stuff

[tmix]

[stainless]

200!!!!! holy sh!% didin't like the cost of the LENRDS either?

[tmix]

ha ha ha!
NOPE I would have spent more for the Acoustic treatments than I did for my equipment!

I had 3 rooms at about 800 sq/ft total with ceilings to treat and 3 deep corners...... still not through actually!

If you ever get curious , you can see some of it here in My build thread (TMIX studio diary?) or check out a couple views at my web site:

www.tmixstudio.com

later,
Tom

[stainless]

I followed your RP thread, but after going to your web site, didn't realize how spacious a place you have (compared to my place which takes up what used to be the family room and garage... ~450 sq ft... more or less as the control room is still a throughfare to an upstairs room and the backyard)

Very Nice!

[bodaddy]

@tmix. Wow, nice looking place. Mine stays just the oppisite. It only looks like yours(all clean and organized) about 10 minutes before a band shows up. lol

I like how your control area is bordered by the booths. And your cieling looks good. Do you like having your control area out rather than in a booth? I was thinking about doing something like that but putting a wall behind where you are sitting and turning the desk around so I could see the main tracking room as well. Do you feel you get better translation with it open though? (I am rebuilding to put my studio at home since I sold my other building(I was gone too much, haha) my wife wanted me closer. We have an apartment connected to our house that we rent out to college kids but are turning it in to the new studio which will be nice because when my wife puts me in the doghouse for being in the studio too much, I can just go live i the studio, lol. I triy to post build pics soon. Thanks

[tmix]

Bo
I guess part of me got used to being right there in the thick of stuff, but I guess ultimately, I felt I did not have enough room to have a large enough control room to be meaningful, AND have a rehearsal room big enough for our band.
That coupled with the fact I often do drum tracks for folks (like here) where I am by myself, I did not want to spend all my time running down hallways and opening and closing doors while running like a mad man to be at my drums before the click started.

Most of the time I record I have the performers out in the room with me listening over speakers while I have the amps and acoustic stuff either in the large drum / percussion booth or the smaller vocal / amp room.
It is also nice when tracking the whole band at once I can let them stay right where they are for play back and not have them filing in and out of the control booth.
At mixdown there is plenty of room for all to sit around.

I guess ultimately it works for me, and recording drums in the big control / rehearsal room sounds great!

Post pics of your place when you can!


Tom

[bodaddy]

[stainless]

Tmix-

It looks like in the pics of your studio that you have panels on the ceiling? Are these flat against the ceiling? or is here a space behind them?

[tmix]

I hung them on chains.
There is about a 6-8 inch air gap behind the perimeter ceiling panels and mix nook panels to allow for the HVAC vents / returns to do their thing (an unexpected benefit is it silenced any residual noise from the air blowing through the vents) and the ones in the center are about 2-3 inches from the ceiling.

It was a bit of a pain in the rear but I'm glad I did it, so that if I want to add more thickness, I can just plop more mineral wool on top.