Tonearm microphonics

I submit that tapping tests are inconclusive or misleading. We know that cartridges (and tonearms) are designed to have resonant frequencies around 10-12 Hz. That’s so acoustic waves won’t excite their natural frequencies (since they the acoustic waves don’t go that low). So it’s the very low structureborne frequencies we should worry about, not acoustic waves or tapping. Isolation, not damping, is the answer. If you don’t like the way tapping sounds don’t tap it. Tapping is not necessarily an indication of anything since most likely nothing natural will have the same impact or amplitude.

Tonearms are designed to have a resonant frequency around 12 Hz or so that they can't  be excited by speaker generated acoustic waves. Tonearms are, however, subject to very low frequency seismic type vibration coming up from the floor which contains vibration in region 0-20 Hz and higher.