Drum set and a brick wall - reducing noise with a PARTIAL barrier/panel


Had a strange software hiccup, but I managed to find an isolated bass drum sound. A rough analysis reveals the absolute highest peak is at around 70 Hz and it peaks quite wide, spans 30-300 (anything around that is much quieter). Interestingly, it still has quite a bit of high end, lowpassing it as high as 6 kHz totally changes the sound. I'd have expected that otherwise but on this particular recording, the pedal had a felt beater and the drum was stuffed with a pretty big blanket and a pillow. (that's one nice thing about bass drums, they can be muffled quite a lot. For quieter practice or if that sort of sound is desired.) Oh, and this was recorded with an NT-1000 from roughly one meter directly in front of the drum. I didn't do any frequency response adjustments yet. I'm assuming the mic's pretty flat.

In any case it looks like somewhere around that low to low-mid frequency range is what I'd most need to absorb or otherwise handle. I'll also have to check the cymbal thing, is it that there's so much LOW mid? Definitely sounds like that's much higher up though, like around 1 k.

Anyway... I was reading more about absorbers etc. and always came across constructions using rockwool. I can't use rockwool (no suitable space, can't deal with the dust etc.) I need something safer. I somehow thought of sasquatch's suggestion to use mattresses. Mattresses are too expensive, at least ones that would have the certain, correct, density needed for these traps/panels. I thought could foam rubber possibly work? I checked an industrial supply store here, they have among other things, foam rubber in several thicknesses and it's reasonably cheap.

But I have no idea what the density of foam rubber is and can't for the life of me find that information anywhere. Anyone here? The density of flooring carpets, neoprene or rubber mats, and others would also be interesting but I can't find that info anywhere either.

I was hoping to get started on building something pretty soon, but damn... there's too much information everywhere and it's not the right kind :/
Mass Loaded Vinyl pound for pound is the thinnest material that actually works. 1/8” has an STC of 26. Expensive.