Vibration Isolation

Based on information supplied by Diversitech personnel, materials used to construct EVA MP2E anti-vibration pads have hardnesses roughly comparable to Tenderfeet from Herbie’s Audio Lab.

Hardness specs for Diversitech’s EVA MP2E 2”x2” anti-vibration pads are as follows:
The black rubber component has a Shore A scale rating of 55 +/-7.
The blue foam layer has an ASKER C rating of 70 +/- 7 [as defined by SRIS 0101 (Standard by the Society of Rubber Industry, Japan)].

Durometer values for various Herbie’s Audio Lab (HLA) components are listed on the site’s Component Isolation “home” page (see link) and are based on the Shore A scale. Values are:

Tender Soft Tenderfoot 46
Extra-Firm Tenderfoot 50
Soft Fat Dot 28
Big Fat Dot 70

Since its hardness rating is based on the Shore A scale, the EVA black rubber can be directly compared to HLA products. The black rubber component of the EVA pad has a Durometer value somewhat greater (i.e., indicating it is harder) than Herbie’s Extra-Firm Tenderfoot (i.e., Shore A 55 +/-7 or 48-62 ~/> EFT 50).

The hardness rating of the blue foam material is more difficult to compare directly to HLA products since it is based on something other than the Shore A scale. Using information from the Rubber Properties pdf found at the misumi-ec link below (see section labeled “Hardness images”), an ASKER C rating of 70 corresponds to a Shore A value of around 45 (ASKER C of 70 falls approximately midway between Shore A values of 40 and 50). Consequently, the blue middle layer of an EVA pad has a hardness roughly comparable to that of a Tender Soft Tenderfoot from HAL (Shore A 45 ~ 46).

https://us.misumi-ec.com/pdf/fa/2010/p2121.pdf
https://herbiesaudiolab.com/collections/component-isolation

Any mass-on-spring system works both for vibrations going up to the component or speaker and those going down. What I had in mind is another layer of resonance control that addresses the “residual vibration” on the top plate of an iso platform, e.g., motor vibration, acoustic wave vibration, what gets through from the floor. There will always be residual vibration because the mass-on-spring iso system acts as a low pass filter, so some relatively high percentage of *very low frequencies* gets through to the component or speaker, depending on Fr. Speaker vibration frequencies don’t extend nearly as low as seismic frequencies, maybe only as low as 30 Hz, so in terms of mechanical feedback speaker isolators work very well, indeed, close to 100%.

+1, been using these for about a year with good results. 

I am perfectly happy with the result: my 2 speakers, and dac and the amplifier are on the same desk...I put each one on one sandwiche constituted by pieces of sorbothane duro 70+Bamboo+ cork plates+granite plate +sorbothane+ another granite plate+quartz pieces... on top of speakers 60 pounds of stones.... Almost perfect isolation to my ears...