Vibration isolation or absorption?

Erik, have you watched all the videos Max Townshend made and put up on YouTube? Worth your time, at the very least.

Actually, Townshend Audio has been in business since 1975. Max started the company to manufacture and market a turntable design that was the end result of intense research into the playback of LP records led by Professor Jack Dinsdale at Cranfield University in England---the legendary Rock Turntable.

The original Townshend Audio isolation product was named The Seismic Sink (introduced in 1989), which was a top and bottom platform separated from one another by from one to three inflatable inner tubes, a very old idea dating back to the 1950’s (WWII-era audiophiles made their own, using bicycle inner tubes and paving stones). I placed my Rock Elite table on one for years---very effective. My Rock now sits on a platform supported by a set of four Seismic Pods, even more effective.

The current Seismic Pod, Bar, Platform, and Podium are state-of-the-art isolation products, the best on the market in the opinion of many. Not cheap, but priced lower than products by the likes of HRS.

The EAR damping products mentioned by @atmasphere are available from Michael Percy Audio, a great hi-fi accessories mail order business. The sheets of EAR damping material (developed for industry) work great at absorbing the mechanical vibrations of the enclosures of electronic components.

For speaker enclosures, bracing is the first defense against cabinet resonances (look at the bracing inside Salk speakers and subs)---they raise the resonant frequency of the enclosure panels above that mostly excited by the drivers, with GR Research NoRez used to mop up what remains. Adding bracing to an already existing speaker is rarely possible (the bracing eats up air space volume inside the enclosure, changing the tuning of the design), but NoRez can be, as it is volume-neutral.