I asked what to use to isolate a 1*12 guitar speaker cabinet sitting on a wood box. Many things in the room are rattling at surprisingly low volume. Herbie suggested Big Fat Dots. And it was suggested I use Tenderfeet between the amp head & the speaker cabinet. I'll report back after I get them.
I was going to use an Auralex Gramma but the size of it wouldn't have worked with the wood box and the Dots aren't going to be as visible. Besides, if I haul the guitar cab somewhere, the Dots are going to be a lot easier to carry than the Gramma.
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After putting the speaker cab on the Big Fat Dots, I noticed a tightened & clearer sound the the lower strings on the guitar had a piano quality. Trying the Gramma, the sound was slightly hollow & harsh and less full.