Go to Orion telescope's website or similar. Celestron, Orion, several others sell liquid filled vibration dampners for telescope mounting isolation from tube and wind vibration, passing traffic vibration, etc. Come in sets of three though
(for tripods.) Maybe you can buy four, heh, heh.
They are miraculous on long period vibration isolation (read, audio bass for our purposes.) Probably will work for higher freqs. too.
So you can tell what they look like here's a link to a random (British) page.
http://www.scsastro.co.uk/it030065.htmI think hi-fi stores sell liquid filled vibration pads too. Maybe even in sets of four.