New isolation platform

Doc B. · 33

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Offline Doc B.

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on: Today at 08:19:37 AM
We have got some momentum going on the new product front. Along with the Subette subwoofer, Sublime subwoofer amp and the Crack Up leg kits being released Matt and I have been playing with an isolation platform. My story is probably a little too familiar to those of you who have been around for a while. But here it is anyway - When I was a senior at Berkeley in the early 80s I did a physics lab in which the goal was to understand and take a hologram. The optical setup sitting on the third floor of LeConte Hall required an incredibly stable platform, which was composed of a huge sand filled platform sitting on inner tubes. It worked amazingly well. Other companies have made isolation platforms with this basic concept in years past. I told Matt I always wanted to do one and we set about working up one that was simple, elegant and effective. Matt made a prototype using a couple pieces of plywood with silicone caulk between to create a constrained layer. He then machined a nice little set of curved "fences" attached to the bottom in order to center a small inner tube under the platform. I also asked for a sand filled version. Being a competent engineer, Matt took measurements with an accelerometer (iPhone with app) on the platform and dropping a ball from a fixed height onto the surface the platform sat on. This was done with and without sand, with and without innertube, etc., until he had a reasonable amount of data to interpret. Turned out the sand didn't do much, but the inner tube and constrained layer worked really well.

The final version is made from sapele plywood for the main platform, with an alder skirt to hide the inner tube. Tests done by dropping a lead weight on the equipment rack shelf upon which the iso platform sat, with my Analog Engineering modded Empire 208 ttable sitting on it, showed about a 7 fold reduction in the peak energy transferred to the iPhone accelerometer placed on the ttable platter vs. the turntable sitting directly on the shelf without the isolation plaform. I call that significant.

Next up was a sonic comparison of platform vs. no platform. The platform definitely cleans up the sound - tighter, punchier dynamics and less of the lower midrange false "fatness" that tends to take away from the natural presence of a recording. It was quite a bit more of a difference than I was expecting. Should work great for amps and preamps too. Those tests are in the near future.

We're working up production and pricing. This will be an assembled product aside from the fact that you pump up the inner tube and put it under the platform.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.