[DSK]

I have some DIY fabric covered acoustic panels on the wall behind the listening position that are filled with fibreglass batts. I would like to replace the batts with semi-rigid panels for more effective absorption that also extends down a bit lower.

Owens Corning stuff is not available and local insulation manufacturers only supply trade or large minimum quantities. Anyone know/suggest where I could find some 50mm thick semi-rigid stuff? My 3 panels are each only approx 137cm high x 45cm wide.

[Red Dragon Audio]

I would start calling those places that carry any brand of rigid fiberglass products and find out what you can get in smaller quantities.

maybe there is a manufacturer in Austrailia or perhaps another brand other than owens-corning might be cheaper.

[Hegemony]

I am having the same trouble.  Maybe there is some way the batts can be squashed into a more compact package to afford the same lower frequency absorption as a rigid type batt...

[DSK]

I am having the same trouble.  Maybe there is some way the batts can be squashed into a more compact package to afford the same lower frequency absorption as a rigid type batt...

It can be achieved in cylindrical bass traps, where the fibreglass batts are compressed inside or between layers of fencing mesh, but is difficult to achieve in flat wall panels that are only 2 or 3 inches deep and need to satisfy WAF.

I've contacted various fibreglass manufacturers and trade suppliers etc, but the problem is that there are minimum quantities and they just don't want to deal with the public ...especially for small quantities. As I'm only concerned in using these wall panels to treat frequencies down to around 500hz, I'm just going to re-build my panels a little deeper but still use the flexible acoustic batts (wrapped in fabric). I would prefer to use the semi-rigid fibreglass panels as they offer superior low frequency absorption for the same thickness, but I am now giving up on being able to obtain some.  

[Hegemony]

I just went to Mitre 10.  They have acoustic fibreglass by bradford.  it comes in rectangles 2000 x 450 or thereabouts.  $25 for six batts.  they are a 1.6 batt.  Maybe that helps, the guy there said they do make a 3.2 as well.

Cheers,
Russ

[DSK]

I just went to Mitre 10.  They have acoustic fibreglass by bradford.  it comes in rectangles 2000 x 450 or thereabouts.  $25 for six batts.  they are a 1.6 batt.  Maybe that helps, the guy there said they do make a 3.2 as well.

Cheers,
Russ

I assume you are referring to flexible fibreglass batts or blanket as used in walls and ceilings, as opposed to non-bendable (semi-rigid) fibreglass panels/boards? If so, this is what I have used in wall panels for the last couple of years ("Acoustitherm" batts: 95mm thick, 1200mm x 430mm, 8 batts per compressed pack) available at Bunnings. They have it in 65mm thickness too.

Unfortunately, the semi-rigid panels are unobtainable by the general public.

[Hegemony]

yeah, thats the stuff, closest I could find, did you find it did the job or was it a bit of a waste of time?

Thanks,

[DSK]

yeah, thats the stuff, closest I could find, did you find it did the job or was it a bit of a waste of time?

Thanks,

Yes, fibreglass (floppy batts and/or semi-rigid panels) are very effective. You just need to use thicker batts to equal the performance of the semi-rigid panels. For example, 75mm thick acoustic batts have very similar absorption specs to the 50mm semi-rigid panels (depending on the density). The fibreglass is much more effective than absorptive foam like Sonex, Willtec etc. You need about 4" thickness of these to match the above fibreglass.

On the wall between my speakers, I mounted an 8'w x 5'h x 3" deep frame stuffed with 3" acoustic batts and with a thick rug mounted over the top. It provides useful broadband absorption down to around 200hz or so and promotes a "quieter" room and better imaging and inner detail.

On the wall behind the listener, I have 3 DIY wall panels (4'h x 18"w x 2" deep) filled with 2" acoustic batts and covered in decorative fabric. They are hung vertically with about 3" space between each. When I first built them I was a little concerned about absorbing too much of the high frequencies so I placed a very thin plastic membrane between the fabric and the fibreglass batts (as used in the ASC tube traps) to reflect the higher frequencies. I had read somewhere that this would reflect everything above 4000hz. However, I later learned that the correct figure was 400hz. As 2" deep fibreglass won't absorb much lower than this anyway, these panels are currently doing nothing. Also, my room still needs a bit more high freq absorption.

So, I am about to remove the plastic membrane, add a 0.5" strip around the front edge (to deepen the frames to 2.5"), fill them with 2.5" fibreglass acoustic batts, and re-fit the decorative fabric. This will be much more effective and should be useful down to around 375hz.

[Hegemony]

Cheers, Thanks for the info.  I am going to build 4 DIY panels about 6' x 2 1/2' and 2" thick and 4 Base traps which will just be similar panels but about 8-10" thick.  I will then re-evaluate.  My room is 8.5m x 4.5m and is brick on 2 sides and fibro cement on the other 2 with a cement floor.  I currently have thickish rugs over about 2/3rds of the floor.

Anyway, will see how it goes.

Thanks again.

[DSK]

Well, a few days back I finally rebuilt the 3 absorption panels as described above. I removed the fabric and plastic membrane, nailed an 18mm (0.75") square rod onto the front edges (to extend the inside depth of the panels to 62mm), filled them with Insulco Acoustitherm R1.5 fibreglass batts (65mm thick), then recovered in the fabric.

All I had hoped for was that they would assist in making the room slightly less reverberant. What I got was a whole lot more. Soundstaging well outside the speakers and more depth too. On top of this, the soundstage is much better balanced and more coherent. By this I mean that the positioning of the performers and the space between them is far more natural. Backing vocals and instruments have more detail and life, yet the lead vocalist has even greater palpability and relief than before, sounding even more real and better articulated. Everything is more dynamic, more alive, more detailed, more real, and more harmonically complete and beautiful. The improvement in PRAT, already pretty good, was surprising. There is also a stronger sense of the venue coming through now and, despite the increase in detail, harmonics and dynamics, the system is easier to listen to and quieter (less phasey or chaotic). I can now turn up the volume further without the loudest female vocal notes becoming irritating, and this no doubt assists with the dynamics. Also surprising, given that these panels are only effective down to approx 300hz or so, was that the bass became more alive ...more detailed, more noticeable and more growly.  

The system was quite engaging before but now I am really there ...the system and walls have disappeared and there is nothing between the performers and me. I have heard far more expensive systems than mine, but none have sounded as convincingly lifelike as this. A good part of this is most likely the room. Due to success in the past with room acoustics treatments I have always recommended that listeners treat their rooms. However, I didn't expect this scale of improvement, or this many different aspects to improve, from just treating the wall behind the listener...especially in a reasonably large room. In retrospect, the music was flat and unfocussed before. For some reason, I had always paid more attention to treating the reflections from the side walls and the wall behind the speakers.  

I know this post sounds a little gushy, but after 8 hours of listening I'm still dumbfounded at the improvment from 3 little panels on the wall 5 feet behind the listener. This from someone who has been involved in this obsessive hobby for many years and already had a greater respect for the importance of room acoustic treatments than most.        

Hegemony, hoefully this inspires you to get cracking with those treatments.  

[HumanMedia]

Anyone know of Australian companies (or DIYers) selling acoustic treatment products for reasonable prices?

There is a RealTrap distributor in Melbourne but their stuff has ridiculous prices.
If I had a workspace or garage (I live in a city apartment) I'd do it myself, but I dont so Im happy to pay for someone/some company to do it.

[MrCool78]

To: Human Media

Anyone know of Australian companies (or DIYers) selling acoustic treatment products for reasonable prices?

There is a RealTrap distributor in Melbourne but their stuff has ridiculous prices.
If I had a workspace or garage (I live in a city apartment) I'd do it myself, but I dont so Im happy to pay for someone/some company to do it.

How much is your budget?
This is one of the cheapest panel in USA,  gotten good reviews:
http://www.gikacoustics.com

I've never bought from them, but I'm gonna give it a try soon


Cheers

[HumanMedia]

Thanks Ive just emailed them to see if they ship to Australia.  Another high quality low cost supplier in the US is ATS Acoustics, but they wont ship here.

One thats more mid priced, but does ship to Australia, is Michael Greens.
http://www.michaelgreenaudio.com/forum/

Any to be found locally?

[MrCool78]

Hi Human Media
Do they(GIK) ship to Australia? before I inquire them

[DSK]

Several years back I bought some RPG products (Skylines & B.A.D panels) through their distributor in Singapore. Even from there, shipping was NOT cheap.

My wife won't let me use the Skyline diffusion panels in the new house, so I have 6 of them (2' x 2') to sell 

[HumanMedia]

Hi Human Media
Do they(GIK) ship to Australia? before I inquire them

On the GIK site they have a page to submit for an international quote (so they do ship).  But Im still waiting for a response. 

I was hoping to get the bass traps from GIK, but in the meantime I ordered a deflection kit from Michael Green.  The prices on Michael Green site seem to be retail.  I seem to have been lucky as the Room Tune kit with Air Mail to Australia cost less than the US Retail price.

[HumanMedia]

Still cant get a response from GIK.  Shame as their prices are (were?) reasonable and offerred international shipping.

An opportunity for a local company to do Bass traps for Australia?  (hint hint)

[jules]

Splendidly laconic this post ... just chalked up two years with the question still hanging in the air 

In relation to your comment "if I had a workplace ......". Would it be possible to source the materials, draw up details of what you want and take the whole lot down to the nearest joinery [or sim. general duties operator] and get them to do the noisy bit? Then you can take the bag of parts home and assemble them quietly at your leisure.

I do this with all sorts of things myself and often find it's cheaper to have something made than to buy it ready fabricated.

go DIY

jules

[DSK]

Still cant get a response from GIK.  Shame as their prices are (were?) reasonable and offerred international shipping.

An opportunity for a local company to do Bass traps for Australia?  (hint hint)

My father bought a pair of cylinder bass traps a few years back from Tivoli Hifi (Camberwell, VIC). From memory they were approx $500 or $600 the pair. Not sure if they still carry them or now carry other acoustic treatments (they didn't back then).

www.tivolihifi.com.au

[lonewolfny42]

Still cant get a response from GIK.  Shame as their prices are (were?) reasonable and offerred international shipping.

An opportunity for a local company to do Bass traps for Australia?  (hint hint)

Have you tried a PM to Bryan.......???