Bass Trap Material...

[malfunction]

this material is available from my local supermarket and i was wondering if it would help me in taming bass frequencies in my room...
http://www.isover.ch/jahia/page271_de.html
unfortunatley the page is only in German (or French and Italian) but perhaps someone here will understand anyway?
Thanx
Grant

[Getafix]

Hi,

I'm living in switzerland as well and am really interested in this since i was looking for somewhere to buy acoustic material from..I translated the pages in english & attached the pictures if anyone's interested!

[Acoustic Cloud]

Beschreibung

Halbsteife Platten aus Glaswolle ohne Dampfbremse, wasserabweisend.
Für Anwendungen ohne Überlast.

Anwendungsbereich

That seems like a good product.

Whats it used for though, being offered in a supermarket??

The Glasswoole name sounds like it is usable......

[malfunction]

Originally Posted by Acoustic Cloud

Beschreibung

Whats it used for though, being offered in a supermarket??

The Glasswoole name sounds like it is usable......

American style supermarket, D.I.Y. kind of place that sells everything imaginable...

[bpape]

The density is kind of low. You'll need some thickness if it's to be used for bottom end control.

Bryan

[loaf]

Is that stuff sealed or something? It looks a bit like the slabs they sell in hardware shops in the uk - I wonder if there is anything you can just put them in so you don't have to build a frame for them if you're only doing a bit of makeshift bass trapping in a small room

[aapee]

Ask this one from Isover. Maybe you could find it from the same store. It should have the right density.

http://www.isover.fi/en/Product%20pa...tuoteseloste=1

aapee

[airmate]

you might want to have a look at this:

http://www.thermo-hanf.de/front_content.php?idcat=46

more info here:

DIY Broadband Absorber - pictures posted

[DeeDrive]

OC 703 density is about 48 kg/m^3 and this stuff is ~20, so less than half the density of 703. I would probably skip it and buy 703 or 705.

[esaias]

Holy shit!

Check out the Paroc ROB 60 rockwool slabs!

175kg / m3 availeable in 30mm thick, 600mm x 1200mm
list price seems to be 6,18eur m2 with 0% vat....

I wonder if it is too stiff, would it act like a resonating plane?

-Tomi

[Mr. Dreq]

Yeah I also still can't decide if I should get the higher density stuff, but 175kg/m² is maybe too much? It would be very interesting to know the density of commercial bass traps like the GIK ones, Realtraps etc.!

[esaias]

I had this idea of building basstraps so that I have the surface layers made from "real" acoustic slabs(~40kg m3, kinda like Paroc AKU or Echophon Classic A) and the inside would have the thicker material.

I'll do some plans right after new year and post them to GS fo your evaluation

-Tomi

[Scott R. Foster]

Originally Posted by esaias

I had this idea of building basstraps so that I have the surface layers made from "real" acoustic slabs(~40kg m3, kinda like Paroc AKU or Echophon Classic A) and the inside would have the thicker material.

I'll do some plans right after new year and post them to GS fo your evaluation

-Tomi

Tomi:

I'd be careful about investing a great deal of time and effort in making sandwiches of different materials - such constructs can behave in unpredictable ways as the sound passes through media of varying gas flow properties and encounters multiple impedance jumps going from one layer to the next.

You generally get more benefit from shopping your local market for the best material [balance, cost, material handling ease, and the import that overall weight of the panel may have to you], and then making your panels of only that one material - of a thickness to match the abilities of the mineral fiber chosen - adding only an upholstery layer that is as sheer [breathable] as concerns of durability and aesthetics allow.

Making stacks of the same material [using two 2" panels of 703 to make one 4" panel] works out fine, as long as you stay away from panels with foil or other scrim facings.

The 4" thickness range is generally held to be the approximate efficiency "sweet spot" for panels made from 3 lbs. to 6 lbs. pcf fiberglass - or 60 to 130 kg/m3 rockwool. Making them thicker makes them better, but you get more Sabines per $ making for example - using 703 - two 4" panels versus one 8" panel. OTOH, with a lower density [gas flow resistance] fiberglass material the thicker panel would yield efficient improvement.

Getting denser than the ranges described above may work - but the cost per panel is bound to rise roughly in line with density and you may not get the results you want. Don't confuse density with performance capabilities. Its all about balancing thickness with gas flow properties - and price with ease in handling and overall panel weight.

I believe that Mini-Traps use 3" of 705 with a felt facing, and GIK's 4" panels use an 8 lbs. rockwool with canvas upholstery. Our standard 4" product, the RT424 has a 703 core - or if you desire we make them using 705 - but I wouldn't suggest you let any of those choices overwhelm your thinking. A manufacturer has a number of concerns arising from the supply process, the manufacturing process, and the shipping of finished unit that would matter little, or not apply to your circumstances. Any material from the ranges described above will work well acoustically - shop for price and ease of handling that match your local market and your project.

Good Luck!

[bpape]

The 175 kg/m3 will work for bass control but is overkill. Something in the 40-80 range will work fine. Also, the thicker you use, the less density you can get by with.

As far as the cost/Sabine, that works to a point. However, doing the 8" thick will yield better control at the bottom end. So, you'll get more 'targeted bottom end' Sabines with the thicker material vs 2x the surface area. All depends on what part of the room you're addressing, what else is in there, what it's to be used for, etc.

Bryan

[NLP]

Originally Posted by bpape

The 175 kg/m3 will work for bass control but is overkill. Something in the 40-80 range will work fine. Also, the thicker you use, the less density you can get by with.

As far as the cost/Sabine, that works to a point. However, doing the 8" thick will yield better control at the bottom end. So, you'll get more 'targeted bottom end' Sabines with the thicker material vs 2x the surface area. All depends on what part of the room you're addressing, what else is in there, what it's to be used for, etc.

Bryan

Sorry for asking, but why would be 175 kg/m3 overkill? Because of high cost of such materials?
Absorbtion above 100-130Hz is relative simple to handle, below 70Hz is very difficult.