Multiple Density Traps?

[embrionic]

I have ended up with a rather large batch of varying densities rigid... Lots of 2.5 inch thick OC "Curtain Wall" (Called OC CW225) which is 2.25 pcf, and lots of 1 inch OC703. Have about equal square footage of each, maybe slightly more of the OC225...

almost all of the OC CW225 and 703 is foil faced. :-)

Was thinking about combining the two into a 3.5 inch trap with a 2 inch airgap:

What do you think? Lots of questions:

OK to combine densities?

Does it matter - if the densities are combined - which side the denser stuff goes on? Obviously the foil faces out and I will remove from the wall side and interior layers - but does the "density order" of materials matter?

3.5 inch thick enough to be effective for bass trapping / broadband?

Suggestions for another arrangements instead?

I should state up front I am trying to compromise between trap thickness / air gap and maximum effectiveness as my room is very small/ narrow.

Will be making some superchunks too, assumed the 2.25 pcf stuff was best for those areas...

Looking forward to getting started and sharing some pictures of the build.

[Glenn Kuras]

OK to combine densities?

You could be fine, BUT.....................

Does it matter - if the densities are combined - which side the denser stuff goes on? Obviously the foil faces out and I will remove from the wall side and interior layers - but does the "density order" of materials matter?

I would think the less dense stuff will absorb a bit more high end, but might work either way.

3.5 inch thick enough to be effective for bass trapping / broadband?

Sorry but NO. Min is 4" when using only the 703. 6" when using less dense.

Suggestions for another arrangements instead?

I would go with not mixing but making 4" panels with the 703 and 6" (filling the corner) with the less dense stuff.

I should state up front I am trying to compromise between trap thickness / air gap and maximum effectiveness as my room is very small/ narrow.

If using some of the panels for early reflection points than us the less dense which can be made to 2"

Will be making some superchunks too, assumed the 2.25 pcf stuff was best for those areas..

.

Yes, then you can make 2" (early reflection points) and 4" panels for the bass traps with the 703.

Looking forward to getting started and sharing some pictures of the build.

[embrionic]

Originally Posted by Glenn Kuras

Yes, then you can make 2" (early reflection points) and 4" panels for the bass traps with the 703.

This seems like the plan thenn Glenn

OC CW225
corner super chunks


OC703
2" RFZ Panels (FRK removed)
4" broadband (FRK or cling wrap on face) with 2 inch air gap.

Make sense?

Couple more Q's -

Any help in using a limp mass membrane, like mover's cling wrap, on the face of superchunks to improve bass absorption?

What about facing the front of the superchunks with 1 inch of the 703, (placing a panel standing up against the face, like this if looking from above:

(back/corner) <| (front/face)

This will certainly provide a clean face for the material to be smooth rather then "the wedge effect". Will it help or hinder performance of the corner trap?

Thanks so much Glenn, as always glad i asked. btw, headin' your way for some FR701 in a few weeks. thnx.

[Glenn Kuras]

4" broadband (FRK or cling wrap on face) with 2 inch air gap.

If you plan on straddling corners then make them 4" and edges should touch the walls or ceiling (depending on how you plan on straddling)

Any help in using a limp mass membrane, like mover's cling wrap, on the face of superchunks to improve bass absorption?

Use the facing that you have now.

This will certainly provide a clean face for the material to be smooth rather then "the wedge effect". Will it help or hinder performance of the corner trap?

It being smooth or not is not going to change the performance of the trap. But putting the 703 on the front will increase the thickness which is a good thing.
BTW I would not put a gap between the 703 and the filled area.

Glenn

[embrionic]

If you plan on straddling corners then make them 4" and edges should touch the walls or ceiling (depending on how you plan on straddling)

I am going to mostly go with superchunks in the corners becaue I have so much of the CW225 stuff, I believe enough to do eight corners floor to ceiling with the 17 x24 design. And it is definitely not quite as rigid as 703...

For the 703 panels I will focus on walls.

Originally Posted by Glenn Kuras

Use the facing that you have now.

For a superchunk design the facing would be removed because it would end up inside the layers, no? So I was wondering about "facing" a superchunk - does it help? Anyone ever tried putting cling wrap on the face of a superchunk, the part that is exposed to the room... or using a layer of FRK 703 (without airgap) as an outer layer right against the CW225?


It's all starting to make sense, I have a big stack of fiberglass that wants to get to work

[Glenn Kuras]

For a superchunk design the facing would be removed because it would end up inside the layers, no? So I was wondering about "facing" a superchunk - does it help? Anyone ever tried putting cling wrap on the face of a superchunk, the part that is exposed to the room... or using a layer of FRK 703 (without airgap) as an outer layer right against the CW225?

Could you not put the facing back on the front? I have never done it but................ Sorry have never used cling wrap, but don't see a problem if you did.

Glenn