The No.1 Website for Pro Audio
 All  This Thread  Reviews  Gear Database  Gear for sale     Latest  Trending
Bass traps enclosed in cardboard boxes? What do you guys think?
Old 15th October 2013
  #1
Lives for gear
 
nms's Avatar
Bass traps enclosed in cardboard boxes? What do you guys think?

Hey gents,

I wanted to run this by you and see what the regulars think of using cardboard boxes as enclosures for thick bass traps. I used this method for the big 18" x 18" floor to ceiling soffits I did in the front corners of my room. Built in 2' blocks it lends itself to easy stacking, configuring, and transport. Lightweight but sturdy enough to stack.

I want to know what you think might be the possible acoustic disadvantages of this method though.

I'd love to hear your thoughts also on a few options I have when doing this:

-One open face (as pictured) which could be faced in a particular direction. How this would influence things (if at all) I'm not sure. Open to suggestion!

-Leave no open face. Seal off the entire thing with Tuck Tape.

-Wrap the whole thing with a layer of fleece followed by the nice stretchy exterior fabric I use.

-Don't bother with the fleece as extra dampening. Just wrap it for appearance.

To reiterate, this is only for front wall boundaries.

I do have a bit more than I'd like in the 180hz region that I'd like to reduce still. I wonder if that would be affected in any way by having those soffits enclosed this way as opposed to a thin wood skeleton frame?
Attached Thumbnails
Bass traps enclosed in cardboard boxes? What do you guys think?-cubes.jpg   Bass traps enclosed in cardboard boxes? What do you guys think?-corner-soffits.jpg   Bass traps enclosed in cardboard boxes? What do you guys think?-stereo-oct-14.jpg  
Old 15th October 2013
  #2
Lives for gear
 
sheggs's Avatar
Yes you can use cardboard boxes to build your bass traps but ideally you want the sides exposed to the room open. The trouble with the fully enclosed box is that it will reflect miss and highs but not in a manner that you may expect and you could find yourself treating the treatment that you have made in your room. Just use the box as the frame and cut out a window on the two exposed sides.
Old 15th October 2013
  #3
Lives for gear
 

You can do a before and after test.
Old 15th October 2013
  #4
Lives for gear
 
nms's Avatar
Yeah definitely. I always do before and after tests with every adjustment to my room. In this circumstance it'd take building another soffit of a different design to explore the differences there though. Since this is the front wall I didn't think any consideration for mids & highs was needed. All but the bottoms 2' of the soffits is cardboard exterior on both outer sides.

I'm hoping Rod, John, Glenn or someone can weigh in on the science here! I mean, all this cardboard.. I wouldn't want it to make my room boxy

I'm about to grab my final bag of Roxul for this room though to finish off a few boundary spots, so now's the time if I need to make changes to the cardboard frames on those soffits.
All panels on sides, ceiling, and rear of the room are cardboard free.

I've done a lot of work to this room and pretty happy with the progress. The low end is flat within +/-2dB down to 49hz where my monitors roll off. Much better results with the soffiits than the triangular superchunks I had prior due to twice as much insulation in the space. Soffits kick much ass!

Old 15th October 2013
  #5
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Soffits kick much ass!
YES THEY DO!!

Can you post the IR file from REW or zip the REW file and post it? I want to view it a bit different then you are.

The box thing is fine as long as they are not in the early reflection points. You don't need to worry about opening up the sides.
Old 15th October 2013
  #6
Lives for gear
 
nms's Avatar
Quote:
Originally Posted by Glenn Kuras View Post
YES THEY DO!!
Can you post the IR file from REW or zip the REW file and post it? I want to view it a bit different then you are.
The box thing is fine as long as they are not in the early reflection points. You don't need to worry about opening up the sides.
Glenn! Would be an honor to have you look over my mdat and offer any treatment advice! I've zipped and attached it. I was actually just watching your video on the scatter plates before seeing your reply! Something to grab in the future perhaps for left and right wall early reflection panels. I'm not sure if my room is large enough for diffusion though. Are things like slats or scatter plates able to actually do anything on the front wall or should that just be implemented for sides & rear?

Measurements were done with a Dayton mic w/cal file. Tweeter to mic was 88cm. Too close to reliably capture the upper frequencies of course.

It's a small room. H= 8' 11", W= 8' 7", and the length is 10ft for half of it and 16ft on the other half. No studio specific wall constructions. The Right wall has concrete behind it (outer structural wall ) which is why you'll notice a significant difference between L & R speakers. Luckily they seem to complement each other though and even out in the low end.

EDIT: I have no panels straddling the ceiling to side wall boundaries so I'm considering putting in either single layer straddled panels or 12" thick soffits, but not sure how necessary soffits would be there. The rear corner on the short 10ft side also has nothing in it so I'm thinking to do something there. I have room for a 2ft x 2ft x 6" thick panel on the floor next to my right soffit (where the concrete wall is) so thinking to do that as well.
Attached Files
File Type: zip NMS-REW.zip (5.82 MB, 111 views)
Old 15th October 2013
  #7
Gear Guru
 
Glenn Kuras's Avatar
Wow for a room that size and doing it yourself, you did a great job. A bit over absorbed on the upper frequencies, but that room is pretty small so without a great deal of planning that would be hard to not do.
How do the mixes translate? Over all how does the room sound?

As far as slats you just want to keep them out of the early reflection areas. Any where else is fine, for the most part.
Video Early or First Reflection Points - GIK Acoustics
Old 15th October 2013
  #8
Lives for gear
 
nms's Avatar
Thanks man! I actually have lots of HF in here. Measurements for that are so flaky though when the mic is 87cm away. I had it pointed straight forward for all measurements. The monitors are aimed a few inches past the mic tip. Mic tip sits at center of where my head is in mix position which I think is optimal for LF measurements. For more accurate HF measurements I'd position the mic tip a few inches behind my head where the equilateral triangle converges.

In my previous room I just had 6' tall superchunks in front L&R and a 6" thick panel between them. 2.5 yrs ago I moved to my current room and have been working on the acoustics a few times a yr. The soffits were the heavy lifters though! I framed a 6" thick front wall -straddle- to cloud panel assembly that contributes nicely as well. Shooting the room with every panel placement & furniture adjustment gives you a good understanding of it all.

The room sounds great but I'll be looking for something bigger when I change cities in another year or so.

I'm dumping another bag of Roxul in there today so I'll see what I can do with it to finish it off and report back! Definitely keeping it to boundaries only. In a room that size should I pull the 4 foam tiles off my left & right side wall panels you think? Some say that in a small room there isn't much in the line of desirable reflections to be had.
Old 15th October 2013
  #9
Gear Guru
 
Glenn Kuras's Avatar
If you replace the foam with something thicker then yes it will help. If the same thickness then it might be just about the same effect. Hard to say though as not all foam is created the same. See the test I did with cheap foam that claims it to be soundproofing on there website.

Comparing Acoustic Foam to GIK 244 Bass Traps
Old 15th October 2013
  #10
Lives for gear
 
nms's Avatar
You can see where the foam tiles are in one of the pics. It's just 4 squares placed in the middle of a panel. I did that over the left, right, and rear wall panels.
Old 16th October 2013
  #11
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by nms View Post
You can see where the foam tiles are in one of the pics. It's just 4 squares placed in the middle of a panel. I did that over the left, right, and rear wall panels.
I don't see any problems with the ETC at a quick look, -20db down to 20ms.
Get to work making some music!
Old 17th October 2013
  #12
Gear Head
 

Three of five corners in my (garage) listening space can't have permanent bass traps, but I could absolutely stack cardboard boxes filled with insulation in those corners and just move them out of the way whenever necessary. For 16"x16" boxes would I need to go with fluffy bat insulation or something more dense like Roxul SafeNSound? In another thread 7' Soffit Bass Trap for boxes 18"x18" it was suggested to use fluffy insulation as something like 703 or Roxul would be too dense. Just making sure the switchover point to Roxul or the like doesn't occur at 16"x16".

- Michael
Old 17th October 2013
  #13
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by tinnitusintx View Post
Three of five corners in my (garage) listening space can't have permanent bass traps, but I could absolutely stack cardboard boxes filled with insulation in those corners and just move them out of the way whenever necessary. For 16"x16" boxes would I need to go with fluffy bat insulation or something more dense like Roxul SafeNSound? In another thread 7' Soffit Bass Trap for boxes 18"x18" it was suggested to use fluffy insulation as something like 703 or Roxul would be too dense. Just making sure the switchover point to Roxul or the like doesn't occur at 16"x16".

- Michael
Go with fluffy when they are that size.
Old 17th October 2013
  #14
Gear Head
 

Excellent, thanks Glen! That means I can get this done this weekend.

A few more questions....do the boxes need to be pushed firmly into the corners so they are touching the wall(s) or will an air gap of about 2" degrade their performance? One of the corners has shelves on one wall corner and a workbench on the adjacent wall corner that will only allow me to locate the stack of boxes maybe 1.5'-2' out from the corner (I'll get a picture uploaded shortly). This being the case, is a stack of boxes here an exercise in futility? The LF response in that corner is pretty strong when I stick my head back into it.
And finally, I'm guessing facing vs. no facing on the FG matters since the cut-to-square pieces will be stacked one on top of another....correct?
Old 17th October 2013
  #15
Gear Head
 

Quick question - would it be overkill to cover softfit superchunk basstraps (outside FRP) with 9.5m wood? Or would it become to much of a tuned trap?
Old 17th October 2013
  #16
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by tinnitusintx View Post
Excellent, thanks Glen! That means I can get this done this weekend.

A few more questions....do the boxes need to be pushed firmly into the corners so they are touching the wall(s) or will an air gap of about 2" degrade their performance? One of the corners has shelves on one wall corner and a workbench on the adjacent wall corner that will only allow me to locate the stack of boxes maybe 1.5'-2' out from the corner (I'll get a picture uploaded shortly). This being the case, is a stack of boxes here an exercise in futility? The LF response in that corner is pretty strong when I stick my head back into it.
And finally, I'm guessing facing vs. no facing on the FG matters since the cut-to-square pieces will be stacked one on top of another....correct?
I would go with no facing since in cardboard.

As far as spacing, I would not over think it. Just get them in the corner. It will work either way.
Old 17th October 2013
  #17
Gear Head
 

Boxes ordered and insulation readily available at multiple nearby locations. Looks like I'm in business for a weekend project and will report back with results. Thanks OP and Glen!
Old 9th October 2014
  #18
Gear Head
 

I was considering using cardboard myself. Mostly because my landloard would kill me if i put 25 screws in the walls, also i have doors in 3 corners. my plan was to use a rectangular box maybe' maybe one sqaure foot boxs stacked to the ceiling. would there be any disadvantage to using a rectangle longer box vs a sqaure.
Old 9th October 2014
  #19
Lives for gear
 
nms's Avatar
I don't recommend 12" x 12" at all. The bigger you can make them, the better. That's more important than shape. Try to go with 16" batts stacked as thick as you have room for.
Old 9th October 2014
  #20
Gear Guru
Boxy

Way back I treated a small vocal room in a 'guerrilla' or temporary manner.
I gathered all the shipping boxes I had and stuffed them with anything absorbent to hand, including large amounts of balled up newspaper! When thumped the bigger ones were very obviously damped resonant.
These varied size boxes pretty much lined a whole side wall to a depth of more than a foot. Big speaker shipping boxes and such. I hung a huge cheap Thomann pyramid foam sheet in front. I have since replaced all of that with two 24 inch wide SSC's and fibre mounted on the wall.
The vocal and acoustic guitar sound is not as good as with the boxes. I will go again. Replace those SSC's with square traps like nms and Glenn's Soffit Style.
Deepen the fibre on the wall, and cover the whole wall. I also intend incorporating a Pyramid foam element near the singer/mic.


DD
Old 9th October 2014
  #21
Lives for gear
 
nms's Avatar
It was an interesting experiment. There was a clear performance boost vs stacking tbe squares of insulation with no box.. even with just a single 24" cube placed along the front wall.
Old 10th October 2014
  #22
Lives for gear
There is a thin corrugated plastic panel material similar to, but more rugged than cardboard, maybe which could offer similar benefits, if one desired something in custom built size, a little more permanent and more finished looking?

Yesterday did an experiment on an area in vicinity of front ceiling-- A space near the ceiling 8' wide, 14" tall, 2' deep. Did before-after testing placing three bundles of safe'n'sound batts stuffed in thin plastic garbage bags. Each packet 24" X 15" X 12", distributed left to right to mostly fill that space with absorption. IOW, a few inches of air space separating each bundle.

The before-after fr and waterfall graphs were near-identical. Very little noticeable difference, and no improvement at all on remaining sonic defects.

Which might make one conclude that this particular ceiling space would be unproductive to permanently trap. Or possibly putting the same amount of material in cardboard or a proper open fabric faced trap would somehow turn the sow's ear into a silk purse?

Improvement from minor improvement with better packaging might seem more encouraging than improvement compared to "no detectable difference".

Would you guess the improvement in this case, packaging the rockwool in a "better" enclosure, might have enough potential to even bother doing the experiment?
Old 10th October 2014
  #23
Gear Guru
Sign in

I would try playing sine waves at your Modal and SBIR notch frequencies. See if there is loud action up there. If not it confirms the lack of benefit in placing traps there.

DD
Old 11th October 2014
  #24
Lives for gear
Thanks DanDan

I got curious about thin garbage bags vs cardboard boxes for temp absorptive traps, and did some testing likely inconclusive but grist for boring data dumps. Not generalizable, but some data anyway.

Measurements attempted as consistent possible, both mains + sub, 80 Hz Linkwitz Riley 24 dB crossover, no EQ, mic at ear height exactly 41.25" from each main monitor. REW 1 M sweeps, 8 repetitions for each measurement.

Test probably conducted better in a bare room. Though the Freq Response isn't ideal, the room already has 8 fairly substantial traps, so the effect of added experimental traps is very minor.

Objectives included looking for "low hanging fruit" for additional trapping, and comparing the performance of 2.5 lb per ft^3 rock wool in thin garbage bags vs cardboard boxes.

Am guessing that in audible bass and perhaps low mids, thin garbage bag enclosure would be very similar to raw exposed rockwool. If floppy sealed over a window to the outside, the thin plastic should show little measurable impedance to audible bass, and so perhaps the same result wrapped around rock wool.

The cardboard might have more resonant panel effect, more high-passing than the thin floppy garbage bag plastic, but I'm too ignorant to guestimate what effect such would have. Different cardboards and sizes of boxes probably matter to ultimate performance.

The bags test condition uses three garbage bags, each containing two batts roxul safe'n'sound rockwool, cut in half. Each bag about 2.45 ft^3 of rockwool, 23.5" X 15" X 12". Total volume 7.34 ft^3.

The boxes test condition uses six identical cardboard office document storage boxes, each which contains 1 batt of safe'n'sound, cut in quarters and stacked. Each box 15" X 12" X 12". Six boxes hold the same volume of rockwool as the bags test condition.

All the freq response charts are 2 dB per vertical division, 20 to 20 KHz. The reference line in black is the 8 previous room traps in default positions. The bags condition and the boxes condition are offset down by exactly 10 dB, both set so that the loudest peak of the test condition is -10 dB lower than the loudest peak of the reference response. Bags condition red trace, Boxes condition Blue trace.

First test, top-front location--

Bags Placement--
Bass traps enclosed in cardboard boxes? What do you guys think?-fronttopbags_web.jpg
Boxes Placement--
Bass traps enclosed in cardboard boxes? What do you guys think?-ctrfronttopboxes_web.jpg
Freq Responses--
Bass traps enclosed in cardboard boxes? What do you guys think?-fronttopbagsboxes_web.jpg
Old 11th October 2014
  #25
Lives for gear
Next test rear center ceiling wall boundary. Space only available for 2 of the 3 bags, and 4 of the available 6 boxes--

Bass traps enclosed in cardboard boxes? What do you guys think?-rtcenterreartopbags_web.jpg

Bass traps enclosed in cardboard boxes? What do you guys think?-ctrreartopboxes_web.jpg

Bass traps enclosed in cardboard boxes? What do you guys think?-backtopbagsboxes_web.jpg

====

Test under desk--

Bass traps enclosed in cardboard boxes? What do you guys think?-underdeskbags_web.jpg

Bass traps enclosed in cardboard boxes? What do you guys think?-underdeskboxes_web.jpg

Bass traps enclosed in cardboard boxes? What do you guys think?-underdeskbagsboxes_web.jpg

====

Also tested both rear corners, but the trend continues so here is only the right rear corner--

Bass traps enclosed in cardboard boxes? What do you guys think?-rtrearcornerbags_web.jpg

Bass traps enclosed in cardboard boxes? What do you guys think?-rtrearcornerboxes_web.jpg

Bass traps enclosed in cardboard boxes? What do you guys think?-rtrearcornerbagsboxes_web.jpg
Old 11th October 2014
  #26
Lives for gear
As best I can see, in the bass, rock wool in bags is near-identical to rockwool in boxes. At least these particular bags and boxes. Perhaps different with some other bags or boxes.

Similarly, high freq performance seems near-identical.

The most noticeable (but mostly trivially minor) differences seem to be in the midrange. In the "not target-rich" environment of my room, the midrange behavior of the bags might be a little better than the midrange behavior of the boxes, but it is hard to say.
Old 12th October 2014
  #27
Lives for gear
 
nms's Avatar
Quote:
Originally Posted by jcjr View Post
As best I can see, in the bass, rock wool in bags is near-identical to rockwool in boxes. At least these particular bags and boxes. Perhaps different with some other bags or boxes.
Although your implementation didn't show it, there's a definite difference between cardboard and plastic. The thickness of cardboard or plastic, the size and shape of the traps, and their location in the room make all the difference.

Where cubes are concerned I would not recommend going with smaller boxes than 15"x15"x24". With cardboard it's also useful to have one face open.
If you were to test floor to ceiling in the front corners with a larger size the differences would be apparent.

If the traps aren't built & placed well enough to perform effectively then it won't make any significant difference what (if any) membrane is used.
Old 12th October 2014
  #28
Lives for gear
 

The cardboard boxes jcjr used show a very slight difference in the lowest lows, but nothing to write home about.
Old 13th October 2014
  #29
Lives for gear
Quote:
Originally Posted by nms View Post
Although your implementation didn't show it, there's a definite difference between cardboard and plastic. The thickness of cardboard or plastic, the size and shape of the traps, and their location in the room make all the difference.

Where cubes are concerned I would not recommend going with smaller boxes than 15"x15"x24". With cardboard it's also useful to have one face open.
If you were to test floor to ceiling in the front corners with a larger size the differences would be apparent.

If the traps aren't built & placed well enough to perform effectively then it won't make any significant difference what (if any) membrane is used.
Thanks nms.

Out of curiosity I did one more test, in one location.

Open Boxes (but still the small boxes) on the top front. About 90" wide, 12" tall, 12" deep.

Bass traps enclosed in cardboard boxes? What do you guys think?-fronttopopenboxes.jpg

Also tested the array staggered front-to-back by 12", and angled, but results are not posted because the results didn't seem remarkably better or worse.

Bass traps enclosed in cardboard boxes? What do you guys think?-fronttopopenboxesstaggered_web.jpg

The Open Box straight across seems a bit flatter in freq response compared to Closed Box or Bags. Black = reference previous 8 traps. Red = bags, Blue = Closed Boxes, Green = Open Boxes. All three tests offset -10 dB from the reference. 2 dB per vertical division.

Bass traps enclosed in cardboard boxes? What do you guys think?-fronttopbagsclosedboxesopenboxes_web.jpg

I'm not expert with spectrograms, but the spectrograms show more visible differences compared to the frequency response. These spectrograms use a border line division for each 10 dB.

Reference
Bass traps enclosed in cardboard boxes? What do you guys think?-reference8traps_web.jpg
Bags
Bass traps enclosed in cardboard boxes? What do you guys think?-topfrontbagsspectrogram_web.jpg
Open Boxes
Bass traps enclosed in cardboard boxes? What do you guys think?-topfrontopenboxesspectrogram_web.jpg
Closed Boxes
Bass traps enclosed in cardboard boxes? What do you guys think?-topfrontclosedboxesspectrogram_web.jpg

Though perhaps similar to divining chicken entrails, in the frequency response plots the Open Boxes condition looks best, but on the spectrograms perhaps the Bags condition looks best, the largest spectral area enclosed by the top 10 dB division lines. Though it could depend on whatever feature one might be trying to "fix".
Old 13th October 2014
  #30
Lives for gear
For temp testing, the boxes, either open or closed, are certainly easier less messy to schlep around to different locations than floppy bags full of insulation.

Am curious how similar it would really be, comparing raw piles of rockwool to piles of rockwool in thin garbage bags. Would be expected to be rather similar in the lows and perhaps in mids. I'm currently too lazy to make a big mess piling up that much raw insulation in the room to find out.

Dunno if either bags or boxes would be a good proxy for a tight open-on-all-sides trap with tight-stretched burlap or other fabric. Maybe if I eventually build a permanent trap for one of these tested locations it would provide partial answer. It would be nice if placing temp containers of some constructions would be a good enough proxy for permanent traps, that one could easily pre-test and somewhat predict the effect of going to all that trouble to build a permanent trap.

Am wondering whether the diaphragm effect of tight-stretched burlap in contact with rockwool might be a significant factor in itself. If I play bass-heavy music fairly loud (concrete floor with vinyl flooring on-top, very little floor transmission)-- I can place the back of the hand lightly against the absorber burlap and feel significant bass vibration on the fabric, so it might be making a significant diaphragmatic contribution. Maybe if I get nerdy on it, place some piezos on some locations and try to measure the amplitudes of vibration of various surfaces, though dunno at the moment for what such numbers would be useful.

By contrast, have been making crude temp experiments with limp mass, large pieces of 30 lb roofing felt suspended behind some of my traps. I can feel a little bit of vibration on the roofing felt limp mass, but not nearly as much as can be felt on the burlap fabric. Dunno if that is good or bad, to be expected or not expected. Maybe the less-perceptible vibration on the limp mass indicates that it is doing a good thing, eating some audio. Dunno.
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump
Forum Jump