Quiz about adding dense mass to a vibration isolation application!

@dadork 

Yeah, I'm experimenting with the Nobsound spring devices too, and I agree they should include springs which are a little less stiff.  So far my results have been that they are pretty effective with four of them placed under my two heaviest components, as well as on top of my Auralex subwoofer isolation platform (under the sub).

But under my four other lighter components, the results aren't as good and I'm looking for other solutions.  Hopefully Townshend will ship out my first set of 4 Seismic Pods soon. I may end up combining two Pods with one foam damped Nobsound under two components.

There is natural resonance of the device versus the resonance of the device environment as it floats on a non-rigid mount. Both of those are on a platform that is vibrating, we presume, at different amplitudes based on the SPL and frequencies.

Not unlike running a sine and random vibe sweep of a piece of electronics for your car, plane, or tank. If the platform was to be your shaker table, then what happens to the device on the floating mount?

Adding the weight to the unit changes its natural frequency but you are still then floating it so now the forces are more about the floating device than the unit itself (assuming the weighted unit is in a non-coupling frequency with the sound, and it actually causes some sort of negative performance across its circuits).

Here's an opposite view, an accelerometer in your car's air bag sensing device must be as close to 1:1 transmissibility with the vehicle "frame" as possible so it gets as pure a deceleration signal it can to tell the bags to deploy. So, in this case, stiff mounting is desired. As long as the PCB in the sensing box is not floating, then the 1:1 is achievable. And we really don't care too much what the natural frequency of the sensing device is as long as it does not cause the accelerometer to misfire on bumps (and it won't due to axis's and severity[G's]).

Since we are not banging our stereos at 10 or 20 G's, presumed negative impacts are on a much lower level but nonetheless rapid cycles. Decoupling our gear from earth is beneficial for the micro-vibrations affecting our sensitive electronics which are not built with vibration in mind like an aerospace black box, for instance.

Of course we float our devices and then put on heavy cables, especially power cables, that carry vibrations back into the unit. And all of this making the presumption the vibrations cause negative sound and they may be enough for us to "hear". 

I do isolate all my gear so each device can try and act as it was designed on the bench and given a chance to perform that way. Can I hear a difference? Not sure, but I like the tweaking aspect and avoid the math because it's a hobby and not the job. ha

Ideally, you want the system resonance to be around 3 Hz.  Compressing the springs to 50% doesn't mean much.  The springs could be compressed to 90% and the isolation affect will be the same as long as the total spring rate and mass make for a (ideal) 3 Hz system resonance.  I am able to get down to 5 Hz on my components using the Nobsound springs and they are compressed to about a 0.200" gap.  So I have no room to add mass (weight on top of my components) in order to get the resonance down to 3 Hz.  Still, 5 Hz provides very effective isolation. The isolation added clarity and detail to the music.   The added detail to the music was distracting at first but now I'm used to it and I could never go back.  

Interesting stuff guys.  @tonywinga ​​​​: What method are you using to measure the resonance in Hz on your components?

A DAC is not a turntable! You could encase it in a block of concrete - no effect upon sound quality! Same thing applies to a digital transport - immune to vibrations. The old analog ideas do not apply!