Vibraplane: Should it be loaded close to limit?

I did hear back from Kinetic Systems and from Sounds of Silence. Tony at KS suggested I contact Steve Klein at SOS as he has more experience with the VP in audio applications. The maximum net design load of my passive 24" X 20" Vibraplane 2210 is indeed 275 lbs. Steve wrote me that there will be audible improvements when pre-loading the unit in the 125-150 lb. range and then diminishing improvements from that point on.

Neither gentleman recommended one type of slab over another but Steve did mention that a critical decision would be what material to use between the slab and the top of the VP. He recommended researching materials from EAR.

My VP arrived today and I think I will start by just setting it up as is and comparing it to my Townshend Seismic Sink. I may end up moving my TSS under my phono amp as I have another one under my pre amp and it did improve the sound. After I live with the VP under my TT for a while, I will experiment with pre-loading it. The unit weights about 150 lbs, so if I add another 150 lbs plus my 30 lb TT, that will be a lot of weight on the top of my rack.

Thanks for all the feedback and if anyone has anything else to add, I would appreciate it.

Great info thanks

I've been poking around the web trying to come up with a BOM list for building something like this. As it turns out, even though I already have a compressor it would cost me at least $1200 just in parts to get the features of the 2210.

Here is a spec sheet for an air spring similar to what is used in the Vibraplanes. The graph at the bottom shows the information Peter was looking for, just not specific to that exact product. Still, we can see how adding mass moves the frequency at which damping is the least farther down the graph. Neat stuff.

Air Spring

Thanks for digging this up Pete, much obliged.

It certainly is an interesting unit. Since my table weighs around 120 lbs, I've also simply placed it on top of the Vibraplane. The active system makes leveling a whole lot easier than the passive version I'd guess - mine maintains level perfectly once you set the three thumbwheels to the correct height (I'm at 3.75 inches for now). The compressor kicks on once every six hours or so, so I either have a very very slow leak, or that's just how it functions...comments on the interval of compressor cycles would be welcome. The compressor is a Jun-Air, and is the most silent air compressor I've ever experienced - you only hear it click on and off; I think they were designed for dental offices.

My initial impressions are of a drop in background noise by several orders of magnitude, not a softening of the sound, but rather a very black background. Low frequencies certainly have better control and articulation, especially way down low. My concern at the moment is the nature of the top plate itself - given that it's non-magnetic stainless steel, the same material as the cones on the bottom of my deck, I notice a bit of stridency introduced into the upper midrange, a quality that was absent with my aluminum top-plate sandbox. I'm guessing I'm getting a bit of 'chatter' due to the two equally hard materials interfacing with slight surface imperfections exacerbating the situation. I'm going to experiment carefully with intermediary materials between the deck and the Vibraplane, either substituting cone material or introducing another shelving layer between the two.

At 180 lbs, the Vibraplane is a two man lift to be sure, so haphazard swapping in and out is not on the agenda. It will be a while before I solidify my thoughts on what, exactly, it brings to the table over alternative isolation methods, such as my beloved sandbox.

Palasr, doesn't the top plate have three mounting bolts? I wonder if a different material could be used.