Turntable isolation platforms

brotw71
Ok, had to look that up. Mass on spring looks effective for isolating turntables through other means. I’m more interested speaker and component vibration solutions that drain sources of vibration to the floor. Haven’t seen many spring solutions for those. I think springs just solve the floor moving up and down problem rather than lateral.

>>>>As I already pointed out, mass on spring iso system operate in both directions, up 🔝and down ⬇️ That’s why you have such devices as inverted pendulums, etc. That’s why everybody and his brother says go watch the Townshend YouTube video on speaker isolation. A video is worth a thousand words. The mass on spring system is used for all (rpt all) isolation applications, including tube and solid state electronics, turntables, speakers, etc. By the way, even cement slabs move up and down, 

brotw70
We’re all talking about the same thing here. I’ve just provided a alternate, general way to understand what’s going on, not just with turntables but speakers and components with noisy transformers as well. Mass on spring works well at low frequencies because of bass energy loss in the spring. Sand is likely needed for the high frequency isolation through absorption.

>>>>At the risk of you thinking I’m picking on you, we’re not talking about the same thing here. In fact, mass-on-spring isolation is better (more effective) as you go up 🔝 in frequency. By the time you get to 25 Hz on the way up 🔝in frequency - even for a modest iso system - the effectiveness of isolation is more than 95%. By the time you get to 30 Hz it’s 99.5%. So, it’s more effective for high frequencies than for very low frequencies. Hel-loo! Not to rub it in too much but mass-on-spring isolation is not due to losses in the spring. It’s more complicated. That’s why it’s called mass-on-spring. It functions as a mechanical low pass filter with a 6 dB per octave characteristic.

brotw69
I look at vibration control through an RF impedance matching background. Spiking heavy speakers or platforms improves sound by rejecting high energy bass frequency vibrations in a suspended wood floor moving up into the component or speaker.

Varying pressures in the floor and around supporting beams due to concentrated weight on spikes causes diffraction or reflection of sound, stopping travelling waves in the wood medium moving up the speaker or component. An abrupt change in density is a fraction of bass frequency wavelengths, rejecting sonic conductance which minimizes cross talk between woofers from left to right speaker or speaker to component. Bass frequencies have the most energy and can morph into higher frequency resonance in cabinets and audio racks.

That is just the start of treatment as I understand it. Performance improves if the fraction of vibration that finds it way up the feet or leaving the feet is attenuated as loss or sound absorption through the use of rubber, sand, isolation feet or platforms - whatever provides wideband absorption of vibration energy.

>>>>I’m not sure I agree with your detective work. What seems clear is that spikes and cones minimize contact area and reduce the contact with compliant or springy materials like carpets/pads. There are several variables just for cones and spikes, e.g. material, shape.

For traditional mass-on-spring isolation devices we know they function as 🔜 mechanical low pass filters 🔙, 6 dB per octave, preventing or at least reducing the transmission of vibration from the floor to the component. The vibration of concern is both the seismic type - traffic, Earth crust motion, etc. - and speaker mechanical feedback and footfall.

If you like sand and sugar and things of that nature you might give some consideration to glass micro beads, perfectly round teeny tiny hard glass spheres, the ones sold for use in airport runways, much more suitable to use in isolation stands since they are more easily moved by external forces which is the hallmark of effective isolation - ease of motion. You can put the micro bead box up on cones or springs for an additional stage of isolation. Throw caution to the wind!