Our hydrophones have arrived from Jez Riley French, so it’s time to start working on the Cosmic Pond hydrophone rig.
Audio signals from the hydrophones will travel through some 50 metres of cable from the pond to our sound installation in the observatory warm room. To minimise noise from electrical and radio interference in the long cables, the first step is to convert the unbalanced connection fitted to the hydrophones to a balanced one for the long cable. Using a trusty Neutrik NTE-1 audio transformer, we can create a simple balun circuit.
We built a test rig with a hydrophone suspended in a bucket of water and made some recordings of Alka-Seltzer tablets dissolving in it, with and without the balanced cable conversion. Results were successful; no buzzing or humming from the leads, just plinking and fizzing from the Alka-Seltzer.
Here’s Cosmic Bucket, a short sound piece made from recordings of our test.
Jez Riley French: