Energy damping or energy transfer?

I've been thinking about this topic some lately. It seems to me that the ideal system would be a combination of isolation and coupling. Depending on where you live, floor- & structure-borne vibration can really kill your hi-fi's low-level resolution, especially for vinyl playback. That's where isolation comes in--air suspensions, sandboxes, squishy feet, etc.--to keep the floor & structure-borne vibes from getting to your component. On the other hand, component-generated and airborne vibration are also destructive to low-level info. In theory, coupling seems to be the solution here, whether it's to a support that dissipates vibrations quickly (constrained layer platforms, some solid wood platforms) or to a support that resists movement in the first place (heavy stone slabs and the like). So my theoretical ideal would be to couple the component to a vibration 'sink', and then to isolate that system via some kind of suspension. This ignores energy storage in suspensions or coupled platforms, and probably other issues I'm unaware of.

This idea is based in part on personal experience. I live near a busy intersection. By far the best thing I've put under my turntable--an unsuspended Rega P3--is a DIY, inner-tube-based air platform. The improvement is not subtle. My theoretical explanation is that the air suspension is isolating my TT from traffic-generated vibrations. Second part of my idea is based on my experience that my 'table sounds better if it has hard feet between it and the suspended platform (made of mdf). The setup is pretty crude, but it will remain in my system until I buy or make something prettier that does the same thing.

I've also put my tube amp on a similar air-suspended platform, but I don't hear any obvious differences with it. With speakers, common sense tells me that the speaker cone's mass is too small a fraction of the cabinet's mass for it to make a difference, but damned if I don't like my stand-mounted speakers better on spikes than on blu-tak. This could have to do with cabinet resonances rather than movement of the cabinet relative to the speaker cone though.

Brent

If you want to maintain dynamic coherence within your system then pursue direct coupling of resonant energy and its discharge to the the higher mass or ground.

That's probably true in most cases. In my case, there's likely more energy coming from the structure of my building than from my turntable. At least that's my guess as to why I like my turntable better with the airbox. But, again, I live near a busy intersection, and I live on the third floor of an apartment building. Between the traffic and other residents' activities & appliances, I may have a higher than average amount of building-borne vibration to deal with.

Brent

1. How about putting that inner tube in a solid box with the inner tube inflated just enought to stick above the top of the box so that the shelf that the TT sits on still floats slightly above the box, but the box itself restricts any lateral type movements that result from vibrations.

That's almost exactly what I'm using. Only difference is that the top of the platform is slightly lower (~1/8") than the top of the box, but there's a big enough gap that the platform doesn't touch the box. It began life as a sandbox. I recently dumped the sand and stuck a 16" BMX tire tube in there. As I said, not elegant, but if it works...

2. Acknowledging Krell man and Stehno's assertion that "nothing can stop airborn vibrations", what if you had a large dust cover that could cover the entire TT and rest on the shelf itself and then weight that down with something quick? Would that work in helping stop airborn vibrations?

I've had similar thoughts, maybe putting a turntable inside a cabinet, & then isolating the 'table from the cabinet/shell. Rega recommends listening to their turntables with the lid on. I would guess that this is to isolate the cartridge & arm from airborne vibration. Consensus on the web is that the lid resonates and transmits airborne vibrations to the plinth & the rest of the 'table, which is sonically detrimental. I prefer listening with the lid off myself.

Brent

Shadorne,

I'll check the Patent Office website & get back to you. . .

As to my thoughts above, it's all speculation. I do prefer the way my TT sounds when it's 'suspended', though. Maybe it would sound even better with the listener suspended too. I'll look for patents of 'audiophile swings' while I'm on it.

Brent