[golgi15]


JOHNS MANSVILLE SPECIFICATIONS.pdf 271k .pdf file

I am posting this thread so that someone can weigh in on the right acoustic panel material to choose for my bass traps. I have access to the line of Johns Mansville 800 series products which seem to fail in line with other products from Owens Corning. I have attached the performance specifications of the 800 series product line. I have bass traps that will allow me to put 4" of acoustic material in the frames. Cost is a consideration for this project and for that reason I am leaning towards the 814 type. Also should I go with a faced or unfaced panel?

 

[Ethan Winer]

A density of 6 pcf, faced type, is probably your best bet for corner bass trap. More here:

Density Report


For panels at reflection points 3 pcf unfaced is better, though 6 pcf (unfaced) is fine too.


--Ethan

 

[arnyk]



Quote:
Originally Posted by golgi15  /t/1469907/acoustic-panel-density-pcf#post_23243917

JOHNS MANSVILLE SPECIFICATIONS.pdf 271k .pdf file

I am posting this thread so that someone can weigh in on the right acoustic panel material to choose for my bass traps. I have access to the line of Johns Mansville 800 series products which seem to fail in line with other products from Owens Corning. I have attached the performance specifications of the 800 series product line. I have bass traps that will allow me to put 4" of acoustic material in the frames. Cost is a consideration for this project and for that reason I am leaning towards the 814 type.

One of the problems related to modeling the performance of porous absorbers is coming up with numbers for "Absorber flow resistivity". It seems that the data sheet linked above is a little light in that area, no?


My method for dealing with this problem is a bit backhanded, but seems to work. I take the sample absorber designs from the absorptive material manufacturer data sheet and adjust "Absorber flow resistivity". to get the frequency versus absorbtion numbers that they claim or as close as possible to them.


If you do not have it, Chris Whealy's porous absorber calculator (XLS spread sheet) can be used this way:

http://www.whealy.com/acoustics/Porous.html


Corning porous absorber material is named by its pounds per cubic foot so Corning 703 has about 3 pounds per cubic foot, etc.

http://www.owenscorning.com/comminsul/documents/Fiberglas700Series.pdf


One of the rules of thumb for designing absorbers is to use less dense material for thicker absorbers.