Fun with Hydrophones

This month I have begun my MA program and so far it seems like it’s going to be loads of fun.

The other folks on my course all seem very nice and they have a diverse range of interests in all kinds of things sound related, from the super high tech, to the very low tech.

So far, aside from the obvious beginning of essay writing, I have mostly been focusing on making some underwater recordings.

I hired out some Jez Riley French hydrophones from the uni’s asset store and have been making lots of recordings with them. Mostly this involves trying to get them to stay underwater by sticking them in slightly awkward places like this:

Results have been varied to say the least but I’ve got some recordings that I’m pretty happy with and the process itself really encourages you to listen and experiment with placement a lot, which has been very fun.

I’ll update this post with some of the recordings I’ve made in the next week or so.

Update: Here’s a recording I made at Bristol Harbourside from the end of a pontoon. I dropped the hydrophone about 4 metres down into the water and came across this terrifying scraping sound. Ten nerd points for anyone who can identify it. My best guess is some kind of sluice/valve thing or some part of a boat (although there were no obviously moving or loud boats around at the time)

DIY Parabolic Mic!

After some months of faffing around and one botched attempt I have finally finished building a rudimentary DIY parabolic mic to use for field recordings. In total, the project probably cost me around £15 and I’m pretty happy with the result.



The materials I used are as follows:
1x Large Plastic Bin Lid
1x Jam Jar Lid
2x Jubilee Clips
1x Wooden Dowel
1x Metal Pipe
1x Lavalier (around £8 from amazon)
Gaffer’s Tape
Cable Ties

The only tools I used were a hacksaw, hot glue gun, drill, ruler, pen and a pair of scissors. The basic idea for my design came from this article and it was pretty simple to construct. I modified their design slightly after calculating (very roughly using the formula found here) where the focal point of my parabola was. Seeing as the bin lid I used as a dish is not a true parabolic curve, it doesn’t reflect quite as well as it would if it was, but i’m happy with it anyhow for the time being.

There are lots of folks out there who have made substantially better parabolic reflectors than me and some who have  constructed their own mics for the purpose. Check out examples here and here for starters.

Field recordings to follow shortly!

Update: Here’s a field recording made with the mic.


Update: I’ve now retired this mic as it was a bit unwieldy, fragile and not that effective. Still a good learning experience for me though! I took the lav mic and repurposed it into a DIY stethoscope mic which you can read more about here.