Just made my first hydrophone contact mic. I’ve been wanting to work with microsounds and field recordings. Hydrophones seem to offer another way to gather sound (as has been discussed here). Playing around with contact microphones that I already had, I wanted to finally get around to making my own.
The first thing I noticed about all the DIY hydrophones is that many are made of plastic and need to be weighted down. Thinking about how I could make this mic with fewer pieces, I opted for a brass plumbing cap. It’s heavy, the piezo element I purchased fit inside of it nicely, and I was able to not only seal it with hot glue, but also fill the entire case with it, for extra vibration reduction. Before filling the cap with glue/gluing in the piezo, I knotted the cable to make sure it wouldn’t pass through the hole in the cap.
Pairing this with my ZOOM F1 recorder / @pulplogic CTACT box, I am able to get some really nice lo-fi recordings from my bathroom sink. Much to explore and other casings, wirings, piezo pieces to test, etc. At this point, I’m happy enough that it’s waterproof and heavy, and looks nice.
A short audio example - first through CTACT box into ZOOM F1, then just straight into the ZOOM F1. The CTACT offers a different sound, with more audio present, but does accentuate different bands of audio.