Originally posted by Ian J
Many people live in attached houses or flats that have thin walls and grumpy neighbours. Sub bass frequencies travel through party walls and floors much better than higher frequencies and you may have to keep it turned down to such a low level that it isn't worth having.
Here is an extract from the front of the B&W Sub-Woofer guide. This is at the front in a bright yellow box in order to draw attention to it.
Courteous warning
Bowers & Wilkins respectively asks all owners of subwoofer systems to take care. All B&W subs are capable of reproducing potentially unsociable levels of subsonic energy. Low frequency sound is incredibly powerful, and users should respect the privacy of others residing withinthe same or even nearby buildings.
Even without a sub in my system, with in room loading my 603's go below 30Hz and can be easily heard outside my detached house

, still got my eye on a ASW675 as next upgrade though.