Red-legged frog with Pacific Chorus frog

dpa-hydrophone-whales-alaska ©BBC

©martyn stewart
These sounds were recorded with a DPA Hydrophone placed underwater in the left channel and a Sennheiser MKH-20 placed above water in the right channel then mixed. (Unfortunately the DPA Hydrophone has been discontinued) The idea wasn’t to get a stereo field but to obtain the surface and underwater sounds of the same species simultaneously. This actual file was used in a TV production on Amphibians.
The deeper croaks are that of the Red-legged frog from underwater.