Mixing absorber material

[kasmira]

The biggest problem is when you introduce a new material with a different GFR, it will cause some reflection which is obviously unwanted.

How can you get the Audimute for so cheap? OC703 costs about $8-9 per panel (~$1.10/sq ft). Stop looking online for prices and call insulation distributors in your area. Audimute doesn't do anything to the low end...I wouldn't imagine the combo to do much either. Go with at least 4" thick panels with a 4" thick airgap if you plan on doing any damage to your low end.

[Jamman]

Thanks.

I'm not looking online.

There is a guy here in town who is leaving town who has a bunch of the audimute and offered to sell it to me cheap. He doesn't want to take it with him.

I've already bought part of my Knauf (OC 703 equivalent) locally. I couldn't buy all that I needed in one trip (filled the car). AFTER I bought some of the Knauf, I got the offer for the audimute.

So the question is whether to go back and get the rest of the Knauf, or use the audimute that is about 1/2 the cost (based on what he offered it to me for) of what I would pay for the rest of the Knauf.

I plan to have panels that are 4" thick with 4" airgap. If I go with the audimute I could buy more of it, so I could potentially make some 6" traps, too.

My Knauf is 2" ( they didn't have 4" ) and the audimute is 2". So - the question is whether 2" Knauf (faced) plus 2" audimute (unfaced) is the same as 2" Knauf (faced) plus 2" knauf (unfaced).

I bought the faced Knauf first.

[kasmira]

Originally Posted by Jamman

So - the question is whether 2" Knauf (faced) plus 2" audimute (unfaced) is the same as 2" Knauf (faced) plus 2" knauf (unfaced).

I bought the faced Knauf first.

No. If you can find the gas flow resistivity of the absorbents you can then put them in an absorption calculator to find out how they will perform, but there isn't a real way to estimate this without knowing.

[Jamman]

Thank you, Kasmira.

[OpusOfTrolls]

You should put the lower GFR material on the back of the panel (part closest to the wall).

[Jens Eklund]

Originally Posted by OpusOfTrolls

You should put the lower GFR material on the back of the panel (part closest to the wall).

[OpusOfTrolls]

Originally Posted by Jens Eklund

Attachment 300017

And what device achieved those GFR numbers? Also, did it take diffraction into account?

[Jens Eklund]

Originally Posted by OpusOfTrolls

And what device achieved those GFR numbers? Also, did it take diffraction into account?

All the info you request is included in the screen shoot. Click the thumbnail to enlarge it.

[Jamman]

Thanks everyone for all the info!

[kasmira]

Originally Posted by Jens Eklund

Attachment 300017

Just to boot, he's doing 2" and 2", not 4" and 4"

Porous Absorber Calculator - Results

Much lessened differences between the two with only a 100mm total depth