absorbing 400hz-1.8khz

[kgveteran]

My new setup calls for shelf mounting my monitors (not real happy about this,but ).

As you see in the pic there is some of the shelf below the midrange.There is also an edge of the shelf too.

I want to place wool felt below the mid to absorb sound. How thick should the wool felt be to absorb most of the midrange sound that will want to bounce off that edge ?

[Chris D]

Don't quote me on this, but I think that for mid-range freqs, you want to have thick, heavy stuff. If I were absorbing mid-range, I would intuitively think of something other than wool. Perhaps another expert would weigh in here.

[warnerwh]

Being as a 400hz wave is 10.2" long, the felt won't do anything at all. For 400hz you should probably have at least 2 thicknesses of rigid fiberglass to do any good. Why not pull the speakers out so the baffle is in front of the shelf?

[kgveteran]

Being as a 400hz wave is 10.2" long, the felt won't do anything at all. For 400hz you should probably have at least 2 thicknesses of rigid fiberglass to do any good. Why not pull the speakers out so the baffle is in front of the shelf?

I can't get the baffle out too far, because it will get closer to the aleady too close acoustically transparent screen.

I do have some 2" thick OC 713 board left over from another project.

Thanx guys

[kgveteran]

After looking over what scraps of 2" OC board I have on hand, I'll be cutting a piece for each speaker to sit on. It will be the lenth of each monitor and stick out enough so the sound will hit the 2" piece of insulation instead of the wood shelf. Maybe this will be enough.

KG