https://www.zachpoff.com/resources/building-contact-mics/
Contact mics' signal can be recorded and analyzed in eg. REW and Audacity. Response linearity remains a big question. Typically we look at resonances as waterfall of decay/freq
Contact mics' signal can be recorded and analyzed in eg. REW and Audacity. Response linearity remains a big question. Typically we look at resonances as waterfall of decay/freq
Ditto the contact mics. I have a few, they work well as long as you have a high input impedance preamp. If you don't, you won't get much bass at all, which you do want for measuring cabinet resonances.
An easy accelerometer that is low impedance and biased toward low frequencies is to use a small speaker as a microphone and add weight to the cone. You could probably add 10 grams or so to something kind of like this and have something that is relatively flat from low frequencies up to several hundred or even 1kHz: https://www.parts-express.com/Dayton-Audio-CE40P-8-1-1-2-Mini-Speaker-285-117
You just hold it against the side of the speaker while you do a measurement with REW.
Stereophile uses PVDF piezo film sensors in their cabinet vibration measurements, which probably have the same high impedance problems as the ones mentioned by posters above.
You just hold it against the side of the speaker while you do a measurement with REW.
Stereophile uses PVDF piezo film sensors in their cabinet vibration measurements, which probably have the same high impedance problems as the ones mentioned by posters above.
I believe my thinking was flawed in post #4, typically accelerometers are used "below" resonance, so you would want to use a small press-in tweeter, and somehow seal off the front of it with a small damped chamber to prevent it acting like a microphone. Then you could stick it to the side with blu-tak. If I had a little tweeter lying around I'd try it to confirm.
That one from meniscusaudio looks like it will require the 5V bias from a PC microphone jack to work. I have never tried to use that as the input in REW.
That one from meniscusaudio looks like it will require the 5V bias from a PC microphone jack to work. I have never tried to use that as the input in REW.
You might think so, but the accelerometer in phones is meant to detect phone orientation and shocks mainly, so it won't detect vibrations much higher than 50Hz (if that) as the sampling frequency is limited to about 100Hz.