Materials to use for DIY bass trap/absorbers in australia

[Luke K]

HI,

I am very new to room acoustics and have been reading through various articles and forums extensively. I do realize there have been a few postings similar to this but they were posted a few years back and some of the links in them do not work.
So im trying for a new thread.

I am looking for materials (as the title suggests) to make some bass traps absorbers. I have been looking through various suggestions and the best ones i have found so far are

Bradford soundscreen 3.0

bradford fibertex 350

Are their others that are available in aus? I live in sydney so i would prefer if it is available locally.

If these two are my best options, Which would you suggest and why?

Thanks,
Luke K

[Dayl]

hey mate, I'm in NZ and noticed that Aussie has a distributor for owens corning 703 etc.. look it up. other wise, you will no doubt be able to find some rockwool.

cheers

[Max Dread]

See

Gas Flow Resistivity of Rockwool RW3 and/or Knauf Rocksilk RS60...any have this data?

Bradfords actually publish the gas flow resistivity data for their products - which can be very helpful. Many mineral wool and fibreglass manufacturers don't - and perhaps don't because they have never tested it! So Bradfords is definitely a good choice.....

I'm sure others here will tell you the same, so let me get the ball rolling....:

measure your room

using something like Room EQ Wizard.

This will help you determine what the problems are in your room. Once you know what the problems are, you know what to fix! Otherwise, you are working blindly.

From my own experience.... I'd read this many a time but always shrugged it off thinking A) it will be too much hassle to learn how to measure, and B) surely lots of bass traps and reflection panels is the way to go with or without measurements. So in other words - I've learnt the hard way!!!

Back to your situation, once you have measured the room as it is now - you can use this calculator:

Porous Absorber Calculator V1.58

to figure what your best remedy is. The calculator will tell you which thickness, how much of an air gap, and which gas flow resistivity, etc. works best for ??? frequency. Armed with such knowledge, you will be able to then choose your materials accordingly and (hopefully) successfully.

I'm in a position where the readily available mineral wools in the UK do not have the gas flow resistivity spec and I therefore have to hazard a guess when using the calculator. Stick with Bradfords and you'll take the guessing out of the equation - which is always a nice thing to do!

Good luck

Max

[Luke K]

Originally Posted by Dayl

hey mate, I'm in NZ and noticed that Aussie has a distributor for owens corning 703 etc.. look it up. other wise, you will no doubt be able to find some rockwool.

cheers

I just googled to look again... and only came up with this

John Sayers' Recording Studio Design Forum • View topic - OWENS CORNING 703/705 IN AUSTRALIA - HERE TO PURCHASE:

[Wiz_Oz]

Originally Posted by Luke K

HI,

I am very new to room acoustics and have been reading through various articles and forums extensively. I do realize there have been a few postings similar to this but they were posted a few years back and some of the links in them do not work.
So im trying for a new thread.

I am looking for materials (as the title suggests) to make some bass traps absorbers. I have been looking through various suggestions and the best ones i have found so far are

Bradford soundscreen 3.0

bradford fibertex 350

Are their others that are available in aus? I live in sydney so i would prefer if it is available locally.

If these two are my best options, Which would you suggest and why?

Thanks,
Luke K

I used tontine Acoustisorb 3 ...I got it through ATT controls in melbourne.

cheers

Wiz

[Luke K]

Originally Posted by Wiz_Oz

I used tontine Acoustisorb 3 ...I got it through ATT controls in melbourne.

cheers

Wiz

Cheers, i am looking them up now. No prices listed on the site though...do you remember what you paid for yours?

Thanks

[Sebg]

Get no-obligation quote from

Independent Building Supplies 1300 662 554 for the Tontine (not listed on the site but just email and ask).

Pretty sure they do Bradford as well.

Also can try the Building Materials Mall - buybuildingsupplies.com.au

Have used both online stores with good experiences.

Otherwise, Martini Insulation

Polymax - Specialised Projects

do a product range similar to the Tontine Acoustisorb. Called Polymax Absorb. Ring them direct for suppliers.

Gyprock Trade Centres will sell/supply Bradford insulation if you ring and order.

Can also try:

Eureka Insulation
Patnicar

Sorry, look up the web sites / phone numbers

[gouge]

the tontine is a polyester fibre product, the bradford products are rockwool.

the tontine product has very good test figures. you need to use the 100mm version to get the best from the bass frequencies.

out of the bradfords soundscreen 3 or fibertex 350 i'd go the soundscreen 3 off the top of my head. it's 30kg/m3 and 120m thick, i can't find the absorption coefficient so i'l dig that up tomorrow.

the fibertex 350 test data os for the 50mm sheet which is more common is pretty poor in the bass frequencies. the thicker version should be better but i'm not sure how easy they are to get.

another one to put on the table for bass traps is the bradford anticon 95 thermofoil LD. it has excellent test results. but doesn't perform as well across the whole spectrum as the tontine.

http://www.bradfordinsulation.com.au...50d8e2f453.pdf

[Sebg]

Gouge,

most of the time, corner bass traps are constructed using plain insulation rather than foil-faced insulation like the LD thermofoil you mention.

[chrisjade]

Originally Posted by Luke K

Cheers, i am looking them up now. No prices listed on the site though...do you remember what you paid for yours?

Thanks

i used acoustisorb too.
works well.
and there is less of a safety issue.

[gouge]

Originally Posted by Sebg

Gouge,

most of the time, corner bass traps are constructed using plain insulation rather than foil-faced insulation like the LD thermofoil you mention.

yep it is, but, my understanidng is that foil backed products with the foil facing into the room achieve better bass attenuation.

[Luke K]

Originally Posted by chrisjade

i used acoustisorb too.
works well.
and there is less of a safety issue.

If i did buy the acoustisorb how would i be able to use it without attaching it (gluing etc) it to walls? (i am renting so things have to be removable with ease)

Can i glue it to some kind of backing material?

If i was going to go the bradford (or related options) i would build a frame and lean them into the corners as much as possible. Would not be able to do from floor to ceiling though but i would try and build them as high as is practical.

Thanks for the help...it has me thinking more.

Luke K

[Luke K]

2 Acoustic Foam Bass Traps - Free Delivery | eBay

Was just looking around on ebay and i found this.
It claims to have these specs

Dimensions: 600mm (h) x 300mm (w) x 300mm (w)
Frequency NRC 125 Hz 1.25 250 Hz 1.26 500 Hz 1.47 1000 Hz 1.42 2000 Hz 1.24 4000 Hz 1.29

Too good to be true? I am led to believe foam does not really have such a good rating.

Luke K

[gouge]

i'm not familiar with that product. i'd ask them for new zealand standard test certificates before i believed their figures.

i also spoke with bradford today, they have no coefficient data for the soundscreen. very odd. they must want people to buy a more expensive product.... lol.....

it is nearly identical to their old product which was a rockwool ceiling insulation. that had excellent test results and is listed in their acoustic design handbook. however as there is no specific evidence for the soundscreen i can't recommend it to be used. a qualified acoustic engineer might be able to though.

bradfords advised me that they recommend the fibertex 450 for bass traps. but didn't say what type of bass trap. looking at the fibertex data i can't see how it is the best choice for a bass trap. so not happy with that answer i looked further and thought the ultratel might work for your purpose.

for a cheap bass trap you could get some 75mm hardies ultratel (it's rigid), give it a very light coat of black paint to the foil side and just hang it in the corner from the ceiling with the foil facing inwards.

or you could leave it unpainted and glue on the foil side (or screw from the non foil side) some dressed and stained pieces of 19x19mm hardwood in a random pattern to make it look nicer. think shoji screen, mondrian, whatever looks good. :-)

that would work very effectively as a bass trap.

edit - forgot t oadd, if you use screws you need to cut away the batting as you don't want to compress it.

[Luke K]

Originally Posted by gouge

i'm not familiar with that product. i'd ask them for new zealand standard test certificates before i believed their figures.

i also spoke with bradford today, they have no coefficient data for the soundscreen. very odd. they must want people to buy a more expensive product.... lol.....

it is nearly identical to their old product which was a rockwool ceiling insulation. that had excellent test results and is listed in their acoustic design handbook. however as there is no specific evidence for the soundscreen i can't recommend it to be used. a qualified acoustic engineer might be able to though.

bradfords advised me that they recommend the fibertex 450 for bass traps. but didn't say what type of bass trap. looking at the fibertex data i can't see how it is the best choice for a bass trap. so not happy with that answer i looked further and thought the ultratel might work for your purpose.

for a cheap bass trap you could get some 75mm hardies ultratel (it's rigid), give it a very light coat of black paint to the foil side and just hang it in the corner from the ceiling with the foil facing inwards.

or you could leave it unpainted and glue on the foil side (or screw from the non foil side) some dressed and stained pieces of 19x19mm hardwood in a random pattern to make it look nicer. think shoji screen, mondrian, whatever looks good. :-)

that would work very effectively as a bass trap.

edit - forgot t oadd, if you use screws you need to cut away the batting as you don't want to compress it.

I googled the hardies ultratel but could not find links to buy it...do you know of suppliers?
Also what are the specs on it? do you use it yourself?

thanks

[gouge]

my apologies, it's not hardies it's bradfords, that was a typo. work clouding my mind again.....

http://www.bradfordinsulation.com.au/Bradford/UploadedFiles/5a/5a88221e-2a5d-43aa-8cb7-86c8b9c54e51.pdf

it haven't used it myself as my bass traps are built in, but it's been specified on projects i have designed by acoustic engineers for hvac systems. it's test figures (only part of the picture) are very good,

for the type of trap i described above (which is hanging) you need to use a rigid type board and not the fluffy stuff otherwise the whole build needs an mdf board to stiffen it.

the ultratel being a rigid type product lends itself to the design i mentioned above. i believe it is very similar to the UC 703 product if that helps. should be available from hardware shops via order.

the other item is that hanging the panel with an air gap behind increses it's bass absoroption.

you can also check out bob gold's figures. csr bradford stuff down the bottom.
http://www.bobgolds.com/AbsorptionCoefficients.htm

anticon is very easily available, has very good test figures in the bass region and is foil faced (which will hold it together) and would suit hanging traps with a couple of pieces of timber on the face to stiffen them as the design above describes. there are lots of products, you just need to get the product that suits your design.

[Luke K]

One of the issues i have with this is i am renting, So anything i use has to be free standing. Would it work to just lean it into the corner?
Or does it need a frame/stand?

[gouge]

freestanding will still work. you make a frame, fix a base to it and either use a rigid insulation or use the acoustisorb type stuff and hold it in place with chicken wire or glue depending on insulation type.

edit* you can fix the base at 45deg to the frame so it extends into the corner for stability.... hope that makes sense.

you can also use slotted plywood as the face and glue whatever insulation you desire to it. you used to be able to buy a 3mm slotted plywood from the hardware store. it's not as easy to find these days and in the past i've ended up using custom routered and laser cut sheets in commercial applications but that's very expensive. the off the shelf slotted ply used to be very cheap if you can find it at your local hardware store.

most diy'ers build the frame and encase it in acousticly transparent fabric. it's a matter of taste but i'm not a fan of that, i'd rather use plywood or random timber battens to face it with. to me it looks much better.

it doesn't really matter how you put it in the corner, in simple terms the bass notes run along the wall, go through the trap, loose some energy and bounce around in the corners loosing more energy everytime they pass through the insulation.

you can do a google on bass traps and there are pages of details on how to build them. with any of the insulations mentioned in this thread you will get results.

some people prefer no solid facing in front of the traps to reduce higher freq reflections. it's all a matter of aesthetics and function.

[Luke K]

Ok so i am going to go with the glasswool ultratel 75mm, trying to find a dealer close by. sent an email off to bunnings. Any suggestions for good suppliers in the northern beaches sydney?
Thanks for all the help

[gouge]

i'm not sure of specific places.

i always ask the supplier/manufacturer. when you call them you get the sales department usually. they will have a list of resellers and certified installers of the products. you could even try getting a sheet sample to test some bass trap construction. 1 sheet (cut vertically) should cover 2 traps.

in general, if i need technical information i ask the person i first get through to for a technical adviser and they put me through. this is usually my first contact.

[Sebg]

Ultratel (48kg/m^3) would be approx equivalent to Owens Corning 703. (also 48kg/m^3)

Most ppl around here suggest lighter fluffier stuff if you are going to do thick "superchunk" style corner bass traps. And often when 703 or 705 is suggested, ppl are relying on its rigidity as part of its usefulness.

75mm Ultratel "board" has a list price of $55/m^2. I don't know why you would use it at that price in a home studio.

Thicker and fluffier (less dense) would be much more cost effective as an acoustic absorber.

Soundscreen hasn't been tested for absorption as it is a relatively new product in Bradford terms (less than 10 yrs old) and was developed purely for cavity infill applications.

edit: did you ring Patnicar, a Bradford supplier I listed earlier?

[Luke K]

Originally Posted by Sebg

Ultratel (48kg/m^3) would be approx equivalent to Owens Corning 703. (also 48kg/m^3)

Most ppl around here suggest lighter fluffier stuff if you are going to do thick "superchunk" style corner bass traps. And often when 703 or 705 is suggested, ppl are relying on its rigidity as part of its usefulness.

75mm Ultratel "board" has a list price of $55/m^2. I don't know why you would use it at that price in a home studio.

Thicker and fluffier (less dense) would be much more cost effective as an acoustic absorber.

Soundscreen hasn't been tested for absorption as it is a relatively new product in Bradford terms (less than 10 yrs old) and was developed purely for cavity infill applications.

edit: did you ring Patnicar, a Bradford supplier I listed earlier?

I have not made any phone calls yetbeen sticking to looking on websites till easter long weekend is over. I think i have found a good one!

Tontine Acoustic Insulation Polyester

has the range tontine acoustisorb 3

Its in the northern beaches sydney too!

Edit- should i go with the 100mm or the 75mm? I am awaiting a mic to measure my room but im fairly sure its safe to start working on some bass traps for it

[Luke K]

Originally Posted by Luke K

I have not made any phone calls yetbeen sticking to looking on websites till easter long weekend is over. I think i have found a good one!

Tontine Acoustic Insulation Polyester

has the range tontine acoustisorb 3

Its in the northern beaches sydney too!

Edit- should i go with the 100mm or the 75mm? I am awaiting a mic to measure my room but im fairly sure its safe to start working on some bass traps for it

I look at the stats for acoustisorb 2 as well and it seems to perform even better then the acoustisorb 3 and it is much cheaper

http://www.tontineinsulation.com.au/...sion%2010s.pdf

http://www.tontineinsulation.com.au/...sion%2010s.pdf

So tontine acoustisorb 2 100mm could be a good option then?

[Mr Darcy]

Great find on the Acoustisorb insulation, as well as the Northern Beaches supplier. I live on the Northern Beaches (in fact only five minutes away from the supplier's warehouse) , and I also happen to be looking to treat my room.

The performance ratings on the Acoustisorb 2 look good, but I wonder how well it stacks up against the usual studio insulation stalwarts. According to this website, the density of Acoustisorb 2 is only 32 kg/m3, while the density of the Acoustisorb 3 is 48 kg/m3 (here), which I'd think would be much more suitable, although pricier.

[Luke K]

Originally Posted by Mr Darcy

Great find on the Acoustisorb insulation, as well as the Northern Beaches supplier. I live on the Northern Beaches (in fact only five minutes away from the supplier's warehouse) , and I also happen to be looking to treat my room.

The performance ratings on the Acoustisorb 2 look good, but I wonder how well it stacks up against the usual studio insulation stalwarts. According to this website, the density of Acoustisorb 2 is only 32 kg/m3, while the density of the Acoustisorb 3 is 48 kg/m3 (here), which I'd think would be much more suitable, although pricier.

Ah yes i never thought to look at that! thanks!

Where is the warehouse? i looked on google maps and it showed me it was opposite forestway shops in frenches forest...but looking closer on street view it just seems to be houses there?

But yeah very handy and good prices. I live only about 10-15 min away myself.

[Mr Darcy]

I don't think they have their actual address on the website - I assume they'll give it to you when you order. Although, you could almost make a guess where the warehouse would be, either on Frenchs Forest Rd or near Allambie.

[Sebg]

Look at the price in terms of $/kg of product. You are def. paying a lot more for Acoustisorb3. Note that I doubt they actually stock the product in Frenchs Forest, which means the delivery charge may be mandatory. It would be interesting to know.

As an aside, it is worth contacting Martini as well for a comparison price on the equivalent product. Especially if you have to pay anyway for delivery of the Tontine.

[gouge]

an easier product to get is the bradfords R6 gold ceiling batts,

it's about $70 per bag (i think) which should do 2.5 traps,
has a density of 6-7kg/m^3
gass flow is around 5000

but, you need to build it as a superchunk and not the type of traps we are talking about here. so would cost more in mdf/ply

[Luke K]

Originally Posted by gouge

an easier product to get is the bradfords R6 gold ceiling batts,

it's about $70 per bag (i think) which should do 2.5 traps,
has a density of 6-7kg/m^3
gass flow is around 5000

but, you need to build it as a superchunk and not the type of traps we are talking about here. so would cost more in mdf/ply

What are the absorption stats on them? i can only find the R2.0 listed

Also if i was going to use the acoustisorb 3 100mm...would it be better to use 2 slabs per trap? so have it 200mm thick? or just make more panels with 100mm?

[Mr Darcy]

I've gone ahead and ordered a pack of Acoustisorb 2, since it seems to be the best stuff I could find. The readily available alternatives just don't have the same performance, or tended to be more expensive. While the Bradford Gold ceiling batts have similar performance and are available fairly cheap from Bunnings, I would have needed to build proper frames to use them.

I'll post my progress in this thread. The only downside is that my pack of Acoustisorb has to ship from Melbourne and won't be delivered until Monday. No matter, I'll look into building monitor stands in the meantime.