Mark ( dexterslab2013) commented on a video I did on an old SCSI hard drive starting up. He said he had connected a contact microphone to one to record the acoustics better. This got me thinking, and i remembered these little vibration sensors I had picked up a while ago, but had never used.
Lamerholm Electronics Ltd VP6 vibration sensor, now superseded by the VP7 sensor. Designed as a sensitive vibration sensor, with a 0BA mounting. So I got one out of it's little pill box, complete with it's calibration data of 91mV per 'g' at 70Hz, and a self resonant frequency of 17kHz mounted on a 100g steel block. Done 12 May 1978, so it has had 36 years of sitting unused on a shelf. Looked around and got an old low piezo cable, that was used on an oxygen sensor, and soldered it to the 2 lugs on the unit.
So I recorded the startup, using this sensor and a cheap USB headphone interface from flEaBay that was a little more sensitive than the built in audio mic input. Recorded with Audacity, and saved as FLAc and MP3, but the MP3 is 1.8M, so not attachable here.