There's a common misconception that the sound we hear from adjacent wall neighbors is conducted through the speakers' physical coupling to room surfaces such that mounting the speakers on a rubber/soft silicone base might help. This is primarily incorrect. It is the sound waves in their room striking the common wall surface we share with them which vibrates as any diaphragm does. The goal is to minimize the sound that strikes that surface by:
A) adding distance
B) not aiming your speakers' strongest output side, the front, directly at that surface but instead away from that surface.*
C) making the wall surface heavy and sound absorbing, say by hanging a heavy rug on it or filling the wall with a dense, heavy material.
*Unfortunately the sound which most easily migrates from one room to the next, through walls, is largely the bass and the output of most speakers is almost uniform in all directions regarding the bass; it is mostly the highs which you redirect when aiming a speaker, not the lows.
Last edited by m. zillch; 09-15-2015 at 11:48 AM.