a friends system is based in an upstairs room hence carpet over wooden floorboards. as a result the bass from the speakers (b&w 601s2) was traveling through the floor boards and could be felt under his feet several metres away. this was despite the speaker stand spikes resting on metal pucks. to combat this he has attacked wine corks to the bottom of each spike and this problem has all but been eliminated with no loss of sound quality ! might sound daft but it has worked and cost very little !