I don’t have experience with the ambient one. But if they deliver what the specifications are i think it’s better then the H2a.
I’ve been using the h2a a few times couple of months. The pro side: It’s got a really huge signal level and low noise. Much better then my previous diy hydrophones. The downside is there a really steep cutoff of high frequencies above 5kHz or so. Some of my Diy hydrophones did better. So recordings tend to sound very dull.
The Ambient one says it delivers 70Hz to 20kHz.
I’ve done some new recordings and looked at the spectrograms and analyzed some more.
The roll of from the aquarians not so low. Actually i found sounds recorded up to and above 40khz. There seems to be a really strong emphasis on sounds around 1 KHz or so. So it tends to sound very mid sounding.
All sounds above about 6 KHz are much softer in th recording. But when i filter out all the lower frequencies there actually is still a lot recorded on the high frequencies. I think it’s nice to use quite extreme EQ on the recording results.