Tonearm mount on the plinth or on Pillar ?

It’s a little bit difficult to isolate (no pun intended) the vibration caused by airborne Acousitc Waves from the vibration caused by mechanical vibration including seismic type vibration without making some rather elaborate arrangements. But if you could I’m confident you would find that low frequency seismic vibration of the type produced by Earth crust motion, traffic, subways, etc. is by far the worst offender as regards exciting the resonance of tonearm, platter and cartridge, all of which have resonant frequencies around 10-12 Hz or thereabout, well below the lowest frequencies almost all high end audio systems are capable of producing. So, the solution for Verdier and other high mass designs is high performance (very low resonant frequency) seismic isolation. The airborne stuff, by comparison, is relatively inconsequential IMHO.

geoff kait
Machina Dynamica

Atmasphere wrote,

"Unless, that is, if you are claiming you have a damping system so profoundly effective that ***zero*** vibration is the result- if that is the case, then you will have been successful where no-one has been before and the world will beat a path to your door."

i don’t think anyone is suggesting that damping techniques are 100% effective. Nor is anyone claiming that vibration isolation techniques are 100% effective. However, there are two points I’d like to make. One is that - generally speaking - vibration damping techniques, e.g., constrained layer damping, are regegated to frequencies, say, above 30 Hz, whereas vibration isolation techniques, e.g., mass-on-spring methods, are primarily regulated to frequencies between 0 Hz and 30 Hz. And for the latter, vibration isolation, one should address as many of the 6 directions of motion as technically feasible for best results, not to mention attempt to produce as low a resonant frequency for the iso system as possible. Since the resonant frequencies of the cartridge and tonearm as I mentioned previously are circa 10-12 Hz then even such heroic iso means as Vibraplane and some other examples, with resonant frequencies around 3Hz, can provide isolation effectiveness of perhaps only 50-70% at 10-12 Hz. Obviously, obtaining a resonant frequency below 2 or even 1 Hz would be great. Nevertheless, one should do the best one can, including isolating the other gear from seismic type vibration, too.

geoff kait
machina dynamics

The trouble is that the instabilities and so forth in the Earth’s crust and other sources of low frequency vibration actually force the entire building structure, house, apartment building, converted ICBM missle silo, whatever to move like a carpet being shaken such that everything inside the building is also forced to move and all attempts to control this very low frequency vibration with damping methods won’t accomplish squadoosh. This is not to say that damping doesn’t have it’s place. I’m actually a big fan of contrained layer damping in applications such as CD transports, output transformers, the top plate of iso platforms and capacitors, among other things. Even very rigid structures and stiff materials have their place in vibration isolation inasmuch as they can help control bending forces produced by Earth's crust motion.

atmasphere
4,796 posts
05-09-2016 5:00pm
Geoffkait: "i don’t think anyone is suggesting that damping techniques are 100% effective."

to which Atmasphere replied,

"Actually Geoff, I was being accosted about that very thing when I pointed out that it was impossible for any damping system to be 100% effective (perfect)."

Oospy daisy! In that case consider my post to be in defense of your position. As for your point about damping, I actually didn’t address damping effectiveness, only vibration isolation, in my previous post.

Cheers