Audiopoint wrote,
Mr. Kait states: - The only way you can possibly deal wih seismic waves is to decouple the component from them, and I'm referring to rotational (bending) forces in additional to the usual vertical forces and forces in the horizontal plane.
To which Audiopoint responds,
"Your springs are actually functioning as a “direct coupling mechanism”. Depending on the actual materials and dimensions of springs used, the speed of the resonance transfer will vary as will the bandwidth of frequencies across the audible and inaudible spectrum, yielding different sonic results in comparison. Frequency and Speed with springs is complexly related to the mass and mass distribution of the component. We too have used springs in our studies and development processes and have found that there are too many variables in each possible usage scenario; there is no “one-size fits all” with spring coupling. Ultimately, you are ‘NOT Decoupling’ with the use of metallic springs - try another material."
if it weren't so funny I suppose it would be sad but let me clue you in to how springs actually work, not as couplers as you surmise, but as Isolators. It all has to do with what I've been referring in my posts on this and related threads to mass-on-spring isolation, which is the physical principle on which almost all vibration isolation devices are based. Mass on spring isolation requires both springs and mass to accomplish the isolation. The isolation is noted by attenuation of structural vibration according to the characteristics of the low pass mechanical filter, analogous to an electronic filter we are perhaps more familiar with. The mechanical low pass filter behaves such that the roll off of structural vibration begins around the resonant frequency of the iso device. The effectiveness of iso increases with frequency as you would expect.
The mathematics of mass on spring isolation is very simple. It is represented by the equation, Fn = square root (Rs/m), where Fn is the natural or resonant frequency, Rs is the spring rate of the device and m is the mass (load). If there are 4 springs the total spring rate is 4 times the spring rate of an individual spring. That's why my first iso device, the sub Hertz Nimbus, has only one spring: to reduce spring rate and thereby reduce resonant frequency.
There is more to vibration isolation but that's the fundamentals. So, to summarize, springs are not really couplers. They're Isolators. That's precisely why the LIGO project was finally able last year to detect and observe gravity waves the amplitude of which are on the order of the diameter of a neutron. It's because the springs in LIGO's vibration isolation system prevent seismic type vibration such as Earth crust motion from interfering with the optics and electronics of the LIGO detectors. It's the same concept that audiophiles use to prevent seismic type vibration from interfering with laser assmblies, tonearms, stereo cartridges, printed circuit boards, etc. by incorporating mass on spring isolation.
geoff kait
machina dynamica
give me a strong enough spring and I'll isolate the world
