Also created for laboratory environments are the active Halcyonics isolation platforms. TBG has had a great experience with them.
Depleted Uranium is nothing but regular Uranium with a slightly higher U238 to U235 ratio, and is a healthy source of ionizing radiation. Your gonads will love you for the extra attention to their well being!
Depleted Uranium is used in weaponry not necessarily because of its density, but because it enjoys a combination of 'desirable' properties: density of 19.50, extreme hardness, high flamability, and high toxicity. Are you sure you want some of it in your living room?
Lots cheaper, safer, and for our purpose just as hard and heavy is good old Tungsten (W), with a density of 19.25, or if you want to be exotic, try Iridium (Ir) with a wapping density of 22.6. Please let me know if any company introduces an isolation platform ballasted with depleted Uranium. I'll make it a point to shop where that brand is not carried.
Thank you J_Badov, and a very Merry Christmas to you too! Seriously, if you want to experiment with high density ballasts in isolation platforms, Tungsten may be a good way to explore. The Tungsten Company suggests Tungsten is being already applied to isolation devices of sorts. See:
Thank you GeoffKait, I am glad 'sesimic' is but an unofficial variant of good old-fashioned 'seismic'. I was afraid I was confronting yet a new novel Age Physics other-dimensional phenomenon measurable only through Radionics-based apparati. Even in their classic spelling, I am not quite sure I am terribly concerned about vibrations induced by tectonic movements in the Mantle, Crust, subduction faults or otherwise. If they are strong enough to be felt by me, bloating in the midbass will be the very least of my concerns. And if my house were in an area prone to anything more than sporadically occurring microquakes. . . it would be high time to move elsewhere, before anything larger than 'micro' hits that idyllic neighbourhood. On the other hand, vibrations directly or indirectly induced by human presence and transaction -- or by weather -- constitute more realistic targets for musical concern and eventual absorption.