Carpet underlay for sealing bass traps

[trapper]

Hi, I'm new here so "hello" to everyone

I've made some superchunk bass traps and have used thin foam carpet underlay to seal the material in the frames (i.e. airtight material). I understand this will reflect HFs, but will this be a problem for bass traps?

I'd also like to use the stuff for broadband absorbers. I figure this is where it could be a problem. Would covering them in fabric (i.e. over the top of he underlay) resolve this?

Thanks in advance

[Weasel9992]

Originally Posted by trapper

I've made some superchunk bass traps and have used thin foam carpet underlay to seal the material in the frames (i.e. airtight material). I understand this will reflect HFs, but will this be a problem for bass traps?

Not a big problem to do the fronts this way, but I wouldn't wrap it all the way around the trap.

Originally Posted by trapper

I'd also like to use the stuff for broadband absorbers. I figure this is where it could be a problem. Would covering them in fabric (i.e. over the top of he underlay) resolve this?

Don't use it for panels where your goal is controlling higher frequency stuff; that will be a problem.

Frank

[trapper]

nice one, thanks for the advice

so what would the deal be with wrapping the underlay in fabric? I guess the HFs would be partially absorbed by the fabric then reflected back out by the underlay... would these two negate each other? TBH HF is not really a problem in my room, I'm taking steps to tame the mids (more so the lower mids) and lows, so would my approach be counter-productive than, say, not treating the walls with regards to HF (i.e. will it make my top end worse off, or merely 'not as good as it could be without the undelay')?

(btw the underlay is 2mm thick if that helps)

[Weasel9992]

Originally Posted by trapper

nice one, thanks for the advice

so what would the deal be with wrapping the underlay in fabric? I guess the HFs would be partially absorbed by the fabric then reflected back out by the underlay... would these two negate each other? TBH HF is not really a problem in my room, I'm taking steps to tame the mids (more so the lower mids) and lows, so would my approach be counter-productive than, say, not treating the walls with regards to HF (i.e. will it make my top end worse off, or merely 'not as good as it could be without the undelay')?

(btw the underlay is 2mm thick if that helps)

It really depends on the specific nature of the problem you're addressing. Are you treating for a mix position or for a recording space? If it's a mix position then you're looking to create a space where reflections are minimized, so you'll want your high frequency treatment to be as effective as possible there. If it's a tracking space then you can adopt a more hybrid approach depending on the size and shape of the space you're working with.

I know these are kind of general answers, but it's hard to address them specifically and succinctly in the same post.

Frank

[trapper]

The room will be used for mixing. I see your point about minimizing reflections so a cheap solution I can do is to cover the absorbers & traps in thick rugs (or a material of similar characteristics). My problem is the materials I have at hand makes using fabric both costly and time consuming. Underlay has sped up my builds and kept my costs down to a managable budget. I do have thick fabric at hand, but working with it is beyond my skill level (and time requirements )

Again, thanks for the input

[trapper]

any thoughts, anyone?

[trapper]

sorry for the shameless bump but does anyone have any thoughts on wrapping traps & absorbers in air-tight carpet underlay (as in the material is airtight)?

I understand the concerns of reflections but I propose to remedy this with judicious wrapping in heavy fabric. AFAIK, the mids & lows will still penetrate the trap and the heavy fabric will handle HF reflections. Any problems with my line of thinking?