How I built my bass traps (superchunk method)

Here's the way I did the studiotips superchunk bass trap. I'm sure that this design has been posted before, but I just wanted to give my input on it, and share the pictures on how I did it. I did the bass traps about a year ago and have just gotten around to posting these pics! Hope it's useful to someone.. Pic 1 First I bought a bunch of fiberglass insulation. I bought johns manville, and whatever the best was recommended around these forums. It was about $40 per bag. Pic 2 Then, I cut the pieces in half, and then into triangles. I cut them using a drywall saw (if i remember correctly). I also found that you can cut multiple pieces at once - I was able to successfully cut three or four pieces at one time. That saved time. Pic 3 Next, I stacked these triangles up in the corner. They were kind of toppling over, so... Pic 4, 5 I drilled these fish-eye hooks into the drywall and used some wire to secure them from falling over. The wire goes overtop of the stack, then down the face of the stack, then up and behind it, to meet the hooks again. Even though it's not mega-powerful, it was enough to keep them from falling over. (post continues)

Pic 6, 7 I stacked the triangle pieces to the ceiling, essentially in two groupings, each secured with a wire tied around the stack. I also added two small poles. I added the poles by using the silver things in picture 7. Their name escapes me (it's very late at night), but they are basically metal studding/framing pieces which I found in the lumber section. Pic 8 Then I added clear painter's drop cloth around the insulation, to prevent fibers from leaking in the air. I just kind of stuffed the dropcloth at the very top and underneath the bottom of the stack. Pic 9 The final step was to get some fabric from a fabric store and then use a staple gun to staple the fabric to the wood posts I put up. This was excellent and they look great. I made sure to pull the fabric taut so that it would look nice and flat. Very effective: just long fabric and a staple gun. This first pic is of the one next to my mixing desk. Pic 10 Here is another bass trap behind my drumset (not me drumming though.. I wish I could play like he did!. :) ) All and all they are awesome looking and very easy to build. However, it did take some time to figure out how I would be building them. Hopefully this will save you some time. I didn't do any intensive before and after tests, but I did play a test sine wave down to 20 Hz and it was pretty even throughout. I believe that these bass traps are effective. Anyways, this post was done late at night, so it's probably not the most well-written. Maybe I'll revise it later - hope it helps somebody out!! BTW - there was too much foam on the walls next to my mixing desk, but I am redesigning the studio - and definitely keeping these bass traps!

cool. i think your bass trap might be a lot more effective if you remove the plastic sheet in between your insulation and fabric.

my thoughts on that, from my limited knowledge: having the plastic doesn't affect the functionality of the bass trap, at least for the actual bass frequencies. the 1 or 2 millimeters of plastic sheet has almost no effect on low frequency content. imagine standing behind a plastic painter's dropcloth like the ones i used - it offers almost no sound barrier whatsoever. however, the plastic might function similarly to RFK fiberglass, giving a slight reflection in high frequencies. having the plastic does keep the glass fibers in better than not having it, although that may not be entirely necessary either. now, i may be entirely incorrect - in this case, would someone please put me on the right track? thanks, John

NO, you're right; this can also be done with thinner, wall or ceiling absorbers to keep the room a little "brighter"... Steve BTW, moved this to Acoustics and added it to DIY treatments "sticky".

Excellent how-to with photos. 8) Thanks for sharing!! :) --Keith :mrgreen:

John, You didn't mention flame-proofing the fabric. Did you do that or did you buy already flame-proof stuff? When you mount fabric vertically like this, it's ability to burn at an alarming rate is increased. You can get spray-on flame retardant (see References thread at the top of the forums). If you started with flame-proof fabric, an extra 2 points! len

Hey Nice work there John!! BTW, 4mil palstic srim seems the norm for bringing back the high end. How would 6 mil work out, anyone? T

Not familiar with any semi-serious documented test of the diff; although this would be much easier to do than MOST acoustic treatments - just put up all the rockwool you're gonna use, test without plastic, temporarily tack really thin (like painter's drop cloth) plastic up, test exactly the same way/place, tear that down, put up 1 mil, repeat, etc... Steve

Great stuff. great pictures! Thanks for sharing Andre

I did not use flame retardant fabric, nor did I spray the flame retardant spray on. -2 points! I will get some on it soon!

this can also be done with thinner, wall or ceiling absorbers to keep the room a little "brighter"

Do people think the superchunk method is a little too space consuming? Are there increased bass-trapping gains due to the bulkiness? I am building some more bass traps soon, and was planning on using the exact same strategy, unless someone chimes in to say otherwise. I remember this superchunk strategy tested very well while I was researching bass trap designs. Thank you, John

knightfly wrote:

Not familiar with any semi-serious documented test of the diff; although this would be much easier to do than MOST acoustic treatments - just put up all the rockwool you're gonna use, test without plastic, temporarily tack really thin (like painter's drop cloth) plastic up, test exactly the same way/place, tear that down, put up 1 mil, repeat, etc... Steve

I am familiar... get this info out there gentlemen...maybe sticky? Bob Golds? ........ the BBC comes to our aid again on this one http://www.bbc.co.uk/rd/pubs/reports/1992-11.pdf Figure 9 on page 4 of this report shows test graph with plastic and without on a rockwool absorber. The absorption appears to be the same below about 500hz.... so it would be a true broadband bass absorber by the fact that its absorbing all bands (broadband)considered to be "bass" but NOT high frequencies... the thicker the trap the lower the included frequencies of absorption. thank you

That BBC article doesn't even mention plastic. It's refering to something entirely different. cheers john

John Sayers wrote:

That BBC article doesn't even mention plastic. It's refering to something entirely different. cheers john

Hi John.... maybe I put the wrong link... this is the graph I was refering to, in the article , the call it polythene, but on the graph you can see they say plastic peace

Ah - I found it - it was on page 4. thanks cheers john

Cool, thanks for the info!! .14mm plastic. Off to do some testing. T

mike0370 wrote:

John Sayers wrote:

That BBC article doesn't even mention plastic. It's refering to something entirely different. cheers john

[size=18][/size Hi John.... maybe I put the wrong link... this is the graph I was refering to, in the article , the call it polythene, but on the graph you can see they say plastic peace

knightfly wrote:

Not familiar with any semi-serious documented test of the diff; although this would be much easier to do than MOST acoustic treatments - just put up all the rockwool you're gonna use, test without plastic, temporarily tack really thin (like painter's drop cloth) plastic up, test exactly the same way/place, tear that down, put up 1 mil, repeat, etc... Steve

Sorry for the delayed reaction, especially seing I posted right after your post that I now replying to. :o Do you mean anything similar to fig 9 (pdf page 10) in BBC RD 1992-11? Eventually remembering: Andre

"Eventually remembering" - You obviously "eventually remembered" sooner than I did :? Steve

i still think that removing the plastic would help, these traps can act as broadband absorbers too, unless you want them strictly for very low frequencies.

Has anyone actually ever measured the performance of these so called SuperChunks? Just curious - I mean its what you hear vs. doing the correct math or things by the book. But, I am curious as to documented results in relationship to other trap, any/all general bass type traps, tube trap type concepts etc. I mean cutting em triangular to fit in the corner is more for ergo functional reasoning - not for anything else. So, why not just cut squares and stack em and get even more surface area and trapping potential? Like in these photos its not like a square is gonna use up any space that is functional i.e. the triangle cut isnt saving space you might otherwise use, though it probably gives perceived feeling like not so much floorspace is being up by traps. But, if they perform so good, seems like it would be even easier to slice em once into squares and stack em and get more density etc. Additionally, has anyone compared the triangled Superchunks vs. Square Superchunks (i.e. take a package of Rockwool bats 4' long and stack em two high in every corner)...? I guess this concept is the easiest way to go, and know many of you are great advocates of em, and certainly in a basic shaped room (rectangle vs. angled walls) or bad rooms (square or cubes) - this sort of trap or really any deep type trap (John's corner traps or ASC or DIY Tube Traps) makes a heap of sense and is a requirement. I guess scientific data or at least straight up shoot out between them would be nice detailed info to have... Just thoughts - David David

dk01 wrote:

Has anyone actually ever measured the performance of these so called SuperChunks?

Try here for starters. The "Studiotips" in Studiotips Super Chunks. Enjoy! Andre

I've been interested in that thread at studiotips.... were the superchunks they tested 24" wide, or 32"wide? I'm wondering how much mass there were in the tested units.... I was also surprised by the good performance of the MegaLENRDs, better than I expected... but then I didn't realize until recently just how huge (ie, lots of mass) those units actually are....

jwl wrote:

I've been interested in that thread at studiotips.... were the superchunks they tested 24" wide, or 32"wide? I'm wondering how much mass there were in the tested units....

Uhh, I'm confused. Superchunks are by design 32" wide, and material filling the triangle. SCA's (Studiotips Corner Absorbers) (don't you just love proprietary trade names? and this is just a bunch of internet acoustic practitioners! :D ) are the batts vertically postioned, creating a space behind. Enjoy! Andre

I'm referring to the two different cutting patterns on the superchunks site, one of which yields a 34" front (4 triangles from a single 2'x4' sheet), the other of which yields a 24" front (8 triangles from a sheet). On the superchunks page, it says:

A compromise size versus efficiency cut pattern is shown in the cut pattern attached below, but of course bigger is better - so use whatever fits your room dimensions / budget.

So based on that I was just wondering which cut pattern was tested.

jwl wrote:

I'm referring to the two different cutting patterns on the superchunks site, one of which yields a 34" front (4 triangles from a single 2'x4' sheet), the other of which yields a 24" front (8 triangles from a sheet). On the superchunks page, it says:

A compromise size versus efficiency cut pattern is shown in the cut pattern attached below, but of course bigger is better - so use whatever fits your room dimensions / budget.

So based on that I was just wondering which cut pattern was tested.

32".