Yes that worked thanks, I can display the traces with SpectraVue nicely. This is 23Khz to 96Khz. Theres a burble running at 52Khz that could be a street light or something.

Having said that, the link doesn't work in Chrome or IE - I get :- Page not found, but at least you tried. Or like Wernher von Braun said ... “Research is what I'm doing when I don't know what I'm doing” • Go to homepage • Browse

Thanks Justin, and I expect lots of others will find this helpful - Phil

Hello Robert, Only just placed an order for one so its going to be a few days/weeks before it turns up. Initial thoughts are to keep the electronics dry in a U/W camera housing with a waterproof gland on the surface and sink a hydrophone under it. I've made my own hydrophones in the past but unsure of their bandwidth/sensitivity so it might need a preamp. Also I was thinking about 3D printing a case with a rubber seal slot. Much experimenting to be done.

I too am planning to use it for underwater monitoring. The best way would be to replace the microphone with a hydrophone and keep the Audiomoth dry. Cetaceans such as dolphins / porpoises produce sounds up to 140KHz, obviously dynamiting will produce a high energy shockwave with a frequency probably well under 200Hz, but it should be detectable even with the unit in a waterproof camera housing weighted down.