# Tackling the 20hz-100hz waterfall



## Arvtechman (Jul 9, 2013)

I realize I probably should have posted here originally considering my goals. However I am new to home theater shack and REW as well. I won't retype everything here and probably will need my original post moved here. To summarize I have taken measurements with REW and I'm looking to determine the best approach for using sound absorption and/or diffusion panels if needed, but after the REW results I may need a lot of bass trapping...

Original post here:
http://www.hometheatershack.com/forums/rew-forum/68552-room-calibration-level-checks-setup.html


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## hjones4841 (Jan 21, 2009)

Bass traps do make an amazing amount of difference. However, it is almost impossible to make much difference below about 50-60Hz. The wavelength of the sound below there is very large and very difficult to trap - think a foot or so of rockwool or Corning 703 to make even a small dent.

I got into trapping about 3 years ago for my 12x20x8ft HT. I ended up with 5 GIK Monster traps plus R30 insulation above the suspended ceiling. After adding each treatment I made waterfall measurements with REW. I was very successful in getting rid of ringing in the 60-100Hz range and made a small improvement in the 26Hz mode of the room. Again, the difference in the sound of the system was amazing.

I don't want to discourage you. Trapping makes a huge difference in most rooms. I just want to make you aware of the limits of traps in the 20-30Hz range.


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## bpape (Sep 14, 2006)

20-30 is pretty tough to do. I would say that with the right treatment you can impact waterfalls down into the mid to upper 30's. It takes some pretty thick treatment and a decent amount of surface area but it can be done. You can also get into tuned membrane absorbers but again, going that low you need a decent amount of them and they are pretty narrow in function.

Bryan


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