sound proofing

so when you have a huge rack setup, how to you keep its sound from leaving the house? foam doesn't work for sound proofing; however, we want to use it for acoustics. we're renting out a house, so we couldn't do any house construction. i've looked into sheetblocks, but i'm not sure if you could install it on the outside of the wall. thanks!

I answered your question in the Construction forum - please only post questions in one forum; otherwise the answers tend to get spread out and make it too time-consuming for us to keep up. If you choose the wrong forum, one of the mods will move it for you, and you'll automatically be re-directed. Thanks... Steve