Group Buy : Polymax ABSORB XHD 100mm x 1.2m x 2.4m

[Stump]

ABSORB XHD 100mm x 1.2m x 2.4m

Here are some picks.I first used a electric knife to cut it but later use a 9inch grinder with cutting disk.

[Drizt]

Thanks for the pictures. I hope black looks good enough to leave it naked

[Stump]

Thanks ,Im in no hurry to get them covered but will later on.

[Drizt]

Hi Guys,

Someone else pointed me out to these guys -> http://www.megasorber.com/

The P100 seems to be equivalent to the Polymax XHD.

It has a coloured face which means it would look a bit prettier naked

[shogun2]

we just did a music room for a university where we used absorption from I metre up and perforated membrane bass traps below. Works great. Cleaned up the room acoustics nicely. The actual design of the acoustics was done by Hanson Associates in Melbourne. when we purchased the 100 mm fluff there was 3x100 mm. sheets in each pack.

That is a good price. Effectively one pack, if I understand it right, is equivalent to 8 sheets of the 50mm stuff I've used in volume, and they were $70 or so, maybe $77 (GST?). So would cost more like $600. However, rigid fibreglass has a higher absorption coefficient (yep I know you hate the stuff Drizt!) 0.33 for glass, 0.2 for polymax. Hence if using this stuff I'd consider making it more like two sheets thick (200mm) and you end up with about 3 traps from one pack.

Being able to get black is attractive. I'm thinking it could be used behind a perforated membrane without issue. So let's say you build a bass trap with a 6mm perforated MDF membrane, it then becomes both a bass trap and a diffuser very much like an RPG BAD panel. Great for those who really just want their bass trap to absorb bass and low mids, but keep some life in the room. Shogun, do you think this stuff could work nicely like that, without a fabric covering? That's the thing I dislike most about fibreglass, you must cover it to keep the fibres in. The material adds to the cost and it also says to cats "climing toy!"

If anyone is considering this and not sure how to do bass traps, I've written up some info here so you can basically "design" your own:

http://www.hifizine.com/2011/09/bass-integration-guide-part-2/

When are you thinking of ordering Drizt? Is there an option to get 50mm versions?

[Drizt]

I have been in talks with Harvey from megasorber and he has been a wealth of information.

He has done a lot of experimentation and has the data to back up his claims.

I thought this one was rather interesting.... adding an air gap increased the lower end efficiency (absorption)

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Hi Guys,

Someone else pointed me out to these guys -> http://www.megasorber.com/

The P100 seems to be equivalent to the Polymax XHD.

It has a coloured face which means it would look a bit prettier naked

[Drizt]

Hi all,

Looks like I can get what I want now without needing a group buy to get the deal across the line. Please feel free to use this thread to organise your own group buys.

[jrisles]

I don't suppose you considered other material? I have been eyeing off the Bradford range of products.

http://www.bradfordinsulation.com.au/Bradford/UploadedFiles/8c/8c6580e1-8058-4db0-ba4e-016585a4d55c.pdf

Page 7 shows some great sound absorption measurement comparisons for their range of products. It would appear that the Ultratel 75mm R2.3 Premium Ductliner has some excellent sound absorption properties at the range you are looking at 0.69 @ 125Hz & 1.19 @ 250Hz and a pretty good spread at the other ranges too. Having said that i have no idea how much this stuff costs so it might not be as good value for money? Although my gut feel is that perhaps not as expensive because it is a "Batt" after all??

[Drizt]

Good find, the ratings for the Ultratel 75mm looks good. Do you know what the stuff is made of (I had a quick look but couldn't find it) ? I couldn't tell what sizes the stuff comes in either?

I'm set on the stuff I am ordering but this info might help others.

[jrisles]

Good find, the ratings for the Ultratel 75mm looks good. Do you know what the stuff is made of (I had a quick look but couldn't find it) ? I couldn't tell what sizes the stuff comes in either?

I'm set on the stuff I am ordering but this info might help others.

That information can be found on this page

http://www.bradfordinsulation.com.au/Products/Commerical/HVAC/Ultratel.aspx

[Drizt]

Thanks. Looks like it a fibre glass / wool hybrid batt (from what I can tell). I'm not a fan of fibre glass myself but others don't have a problem with it. It certainly seems to be very good for audio applications though.

[Paul Spencer]

If you want to compare materials, look at the absorption coeffs at 125 and 250 Hz as a guide, with emphasis more on 125 Hz, must be with the same thickness.

Drizt, did you go elsewhere, or did they decide to take a smaller order?

[Drizt]

I was able to organise a smaller order elsewhere. I'm also getting getting one panel of the grey facing P100 from Harvey at http://www.megasorber.com/ for my back wall (above the stairs)

[dastrix]

I don't suppose you considered other material? I have been eyeing off the Bradford range of products.

http://www.bradfordinsulation.com.au/Bradford/UploadedFiles/8c/8c6580e1-8058-4db0-ba4e-016585a4d55c.pdf

Page 7 shows some great sound absorption measurement comparisons for their range of products. It would appear that the Ultratel 75mm R2.3 Premium Ductliner has some excellent sound absorption properties at the range you are looking at 0.69 @ 125Hz & 1.19 @ 250Hz and a pretty good spread at the other ranges too. Having said that i have no idea how much this stuff costs so it might not be as good value for money? Although my gut feel is that perhaps not as expensive because it is a "Batt" after all??

Did anyone try this Ultratel stuff? Its got a perforated foil though... maybe not good for broadband absorbption?

[jrisles]

Did anyone try this Ultratel stuff? Its got a perforated foil though... maybe not good for broadband absorbption?

I haven't tried this stuff. But i found an excellent thread on the Home Theatre Shack forum that talks a bit about this stuff. Particularly around pages 17.

http://www.hometheatershack.com/forums/home-audio-acoustics/14456-broadband-bass-traps-build-17.html

Irrespective of whether or not it is perforated what you have got are the "absorption" numbers. So it doesn't really matter what it is made of. And the Ultratel duct liner in particular looks great on paper. It is the numbers that count .... so i wouldn't get too hung up on how it is made to construct these numbers. They are standard tests after all.

[dastrix]

I haven't tried this stuff. But i found an excellent thread on the Home Theatre Shack forum that talks a bit about this stuff. Particularly around pages 17.

http://www.hometheatershack.com/forums/home-audio-acoustics/14456-broadband-bass-traps-build-17.html

Irrespective of whether or not it is perforated what you have got are the "absorption" numbers. So it doesn't really matter what it is made of. And the Ultratel duct liner in particular looks great on paper. It is the numbers that count .... so i wouldn't get too hung up on how it is made to construct these numbers. They are standard tests after all.

Thanks, Im going to use this stuff in a L shape to build a soffit, 2 columns in the corners with a long piece across the top at my front wall. I'd most likely use 150mm of this stuff, so doubled up for bass traps.

Then maybe use a sole, 75mm sheet for first reflections with a 50mm air gap for the side walls... Suitable?

[jrisles]

Thanks, Im going to use this stuff in a L shape to build a soffit, 2 columns in the corners with a long piece across the top at my front wall. I'd most likely use 150mm of this stuff, so doubled up for bass traps.

Then maybe use a sole, 75mm sheet for first reflections with a 50mm air gap for the side walls... Suitable?

I can't actually answer the question as i am about to try this route myself. But have a read of the thread i posted in my previous post as it provides alot of information.

[dastrix]

I can't actually answer the question as i am about to try this route myself. But have a read of the thread i posted in my previous post as it provides alot of information.

Seems like the Ultratel has far better low frequ absorbption , where Quietel is better for higher frequencies, although, only by a smiddgen!

I think the Ultratel looks the best, especially because its available in larger, more suitable sheets

[dastrix]

Seems like the Ultratel has far better low frequ absorbption , where Quietel is better for higher frequencies, although, only by a smiddgen!

I think the Ultratel looks the best, especially because its available in larger, more suitable sheets

I've spent a good day or two comparing products and have made myself a little spreadsheet.

Ultratel 75mm is not available at all. Unless you order 1 tonne of the stuff (Confirmed with Bradford reps and sales guys). 50mm Ultratel is available easily, but its 125hz value drops to 0.34.

I've found the best and most cost effective product, is indeed the Absorb XHD 100m, with megasorber coming in 2nd (its better acoustically, but its far more expensive at $215 ex gst per 2400x1200x100 sheet)

The Absorb XHD after speaking to Sam the rep comes in 4 sheets of 2400x1200x100 per pack at about $372 for Sydney people. $50 for delivery regardless of how much you get if you're in Sydney. That provides far far more coverage the the other products, even Bradford stuff of any type. The Absorb XHD also has 0.49 @ 100hz with a 100mm airgap.

Plugging these numbers including its gas flow resistance into my porous Absorber spreadsheet (Absorb is 13,700 according to the test report I have) gives me an optimal figure of 200mm thickness with 200mm air gap. In doing this youll get:

@ 40hz - 0.5

@ 60hz - 0.6

This should work nicely as bass traps.

I'll be using the Megasorber as side reflection traps, so I've ordered 2 sheets of that and will place a order for 3 packs of Absorb XHD 100

Edited November 4, 2011 by dastrix

[Drizt]

Good to know, thanks for the info.

Mine will be free standing so they will have substantial air gaps to increase low frequency efficiency.

[berun12]

Dastrix, thanks a lot for the research!

To anyone interested in buying smaller quantity of Absorb XHD100 in Sydney area. I would need 1 (max 2 sheets) 2.4x1.2. Anybody else interested remaining of one pack (4 sheets in total, so you can get 2-3)? I can order and share a cost accordingly. Please sent me a message, I dont want to hijack this great thread with details.

Thanks, berun

[Shiki]

Would cutting one sheet in half and placing those 2 sheets across a corner work well as bass traps?

[jrisles]

I've spent a good day or two comparing products and have made myself a little spreadsheet.

Ultratel 75mm is not available at all. Unless you order 1 tonne of the stuff (Confirmed with Bradford reps and sales guys). 50mm Ultratel is available easily, but its 125hz value drops to 0.34.

I've found the best and most cost effective product, is indeed the Absorb XHD 100m, with megasorber coming in 2nd (its better acoustically, but its far more expensive at $215 ex gst per 2400x1200x100 sheet)

The Absorb XHD after speaking to Sam the rep comes in 4 sheets of 2400x1200x100 per pack at about $372 for Sydney people. $50 for delivery regardless of how much you get if you're in Sydney. That provides far far more coverage the the other products, even Bradford stuff of any type. The Absorb XHD also has 0.49 @ 100hz with a 100mm airgap.

Plugging these numbers including its gas flow resistance into my porous Absorber spreadsheet (Absorb is 13,700 according to the test report I have) gives me an optimal figure of 200mm thickness with 200mm air gap. In doing this youll get:

@ 40hz - 0.5

@ 60hz - 0.6

This should work nicely as bass traps.

I'll be using the Megasorber as side reflection traps, so I've ordered 2 sheets of that and will place a order for 3 packs of Absorb XHD 100

Be keen to see your spreadsheet? I have received the following prices from a Bradford dealer on the following products;

Bradford Ultratel 75mm R2.3 Premium Ductliner (Thermofoil HD Perf) - 2400x1200 (2 per/pk) $ 98.30 Sheet

Bradford Ultratel 50mm R1.5 Premium Ductliner (BMF) “ “ ( 3 per/pk) $ 67.60 “

Bradford Quietel 25mm “ “ (2 per/pk) $ 91.00 “

The Bradford dealer made no mention that there would be an issue with getting hold of the Bradford Ultratel 75mm R2.3 Premium Ductliner (Thermofoil HD Perf) which has an absorption co-efficient for the following frequencies;

0.69 @ 125Hz

1.19 @ 250Hz

1.15 @ 500Hz

Your Absorb XHD comes in @ $93.00 per sheet. So just trying to work out the "value" proposition of the Absorb XHD product against the other products listed above? When i am quite sure the Utratel (75mm) has better broadband absorption specs?

Edited November 5, 2011 by jrisles

[berun12]

Shiki, yes thats what I am planing to do. To have a sheet size 60x120 cm placed diagonally in the corner between floor and wall and in few more places. It will also work with wall corners. Other way is filling corners with triangular shape stack on each other so they fill the corner completely. Will work better, but question is how much better and how much more material and money would be necessary for this solution. Alternativly, if you place the panel accros the corner, later you can always fill space behind with less dense insulation, which means cheaper insulation and check it a change fits you.

For me, my room is acoustically reasonable and I prefer to do improvement slowly, step by step rather then do all in once and find its somehow overdone. Thats why I need only one sheet or two.

berun

[dastrix]

Be keen to see your spreadsheet? I have received the following prices from a Bradford dealer on the following products;

Bradford Ultratel 75mm R2.3 Premium Ductliner (Thermofoil HD Perf) - 2400x1200 (2 per/pk) $ 98.30 Sheet

Bradford Ultratel 50mm R1.5 Premium Ductliner (BMF) “ “ ( 3 per/pk) $ 67.60 “

Bradford Quietel 25mm “ “ (2 per/pk) $ 91.00 “

The Bradford dealer made no mention that there would be an issue with getting hold of the Bradford Ultratel 75mm R2.3 Premium Ductliner (Thermofoil HD Perf) which has an absorption co-efficient for the following frequencies;

0.69 @ 125Hz

1.19 @ 250Hz

1.15 @ 500Hz

Your Absorb XHD comes in @ $93.00 per sheet. So just trying to work out the "value" proposition of the Absorb XHD product against the other products listed above? When i am quite sure the Utratel (75mm) has better broadband absorption specs?

Call bradford again, you cannot get the 75mm stuff in Ultratel that works 0.69 @ 125hz, i would have got that if you could. The next best thing is Megasorber (expensive) or Absorb XHD.

I just paid $815 including gst and delivery for 2 packs of Absorb XHD. I also purchased 2 x 2400x1200x100 mm sheets of Megasorber that should arrive this week. Ill be using the Megasorber as the material with an airgap for my side reflect poins and using Absorb XHD as my corner bass traps and also the overhead soffit.

Cheers