Sound Proofing Effects of Sofa/Shelves Against wall Questions and answers on many aspects of soundproofing areas of your home

[LordLiverpool]

It's said that putting heavy furniture (especially soft furniture) against a wall reduces the noise coming through the wall. I wondered, does this work just by blocking the sound in the area covered, say, by the sofa, or does it reduce vibrations and therefore sound transmission in the whole wall?

[DNJohnston]

You will get a very minor improvement from the soft furnishings basically "absorbing" a bit of the sound energy which comes through the wall. This is unlikely to be more than 1-2dB and would make no difference if you were actually sitting on the sofa. If you covered the whole wall with large objects you would see a minor reduction. If your problem is that the wall is 'loose' (e.g. a single layer of plasterboard on a frame) then bracing it by pressing a sofa up against it can stop it resonating, but again the improvements would be minor.