703 and 705 Mixed?

[jonmmartin]

Would it be beneficial to glue 2" 703 to 2" 705 for more broad band absorbtion? Can you get the benefit of both this way?
Thanks for the help.

 

[bpape]

Certainly. If you want the ability of the less dense 703 for grabbing shallow reflections but still want the extra density, mount the 703 exposed to the room and the 705 behind it.

I'll say again what I've said before though - for the price of 705, you can buy almost double the quantity of 703 - so for the price of 2" 703 and 2" 705, you can almost but 6" of 703 which will do a better job. If you already have the materials or don't have the room to do 6", the mixing is a good way to go.

 

[jonmmartin]

Thanks for the reply...So if I read you correctly... 4" of 705 is better than 2" of each. Also, did you say that 705 is less expencive then 703?
Thanks again.

 

[Innovations]

Thanks for the reply...So if I read you correctly... 4" of 705 is better than 2" of each. Also, did you say that 705 is less expencive then 703?
Thanks again.

Other way around. The 5 is more expenisve. The 3 and 5 in the numbers represent the density in pounds per cubic foot. The 705 has more fiberglass in it than the 703 (and the 703 therefore has more air) Since air is a lot cheaper than fiberglass of course the 703 will be cheaper. So unless space is constrained it usually makes more sense to just go with a thicker stack of 703 on a bang for the buck basis.