I wanted to share my finds and give recommendations to you on this awesome material. I had been looking for the perfect dampener for my diy transmission line monitors for a while (Statement monitors from HTguide.com). The acoustic foams in the transmission tunnels had such a significant effect on the midrage that soundstage, imaging, distortion, dynamics were all being dramatically affected by the material choice. Naturally I went ahead and tried every kind of acoustic damping I could get my hands on. These are the stuff that I used, listed in descending order according to their ratings.
bonded polyster sheets- almost useless
eggcrate foam
sonic barrier (from partsexpress)
sonic barrier on top of vinyl deadner (also from PE)
sonic barrier on top of cork sheets
polyfil
polyfil +steel wool mix
and then for a huge leap in performance here comes...
3M Thinsulate!
this stuff is so good that my transmissions now sound almost like open baffle. sonic barrier did wonders for resonance, much better than the eggcrate foam. but since it's not porous enough it affected air volume and the dynamic would suffer. vinyl deadner and cork sheet helped additionally but they both brought their own coloration to the sound. Polyfil+ steel wool was the best compromise but I still wasn't satisfied. I wanted something that dampens so well that it killed resonance like cork+sonic barrier but took up barely any air volume. then I tried thinsulate. It does everything I wished for and has no weaknesses. Of course I didn't try fiberglass but I hate the stuff for the dust and plus the tunnels are out in the open where children can stick their arms into.
I was so impressed with thinsulate that today, I tried modding my AKG K271 with it. And it was a success :). Previously I tried damping the inside of the cups with polyfil for improving the bass. But the the drums always came out damped and recessed. But today I cut some thinsulate into circles and put them in. and bam, it opened up, the bass is much more powerful and deep. Give this material a try next time. I don't think you'll regret it.
