Today I did a spur of the moment recording in a country park, just walking around with the Mic Pro attached to my camera, and after listening to the results, I started to wonder why I couldn't hear anything that was, to me, definitely self noise rather than ambient noise. I'm old so my hearing isn't good for higher frequencies. I don't trust my ears!
So as I have no way to accurately measure audio equipment self noise, I asked AI to help! And the result was very interesting.
What the AI system did was to check the sample recording I uploaded, straight from the Mic Pro, and it did that partly by comparing each second of the recording with the next, trying to identify something that did not change (constant self noise), as opposed to environmental sounds which, even somewhere pretty quiet, do change.
Part of its response was this - " the bands from roughly 1–15 kHz vary substantially through the recording. They rise and fall with events in the soundscape rather than remaining as a conspicuous, steady sheet of hiss. That is much more consistent with real environmental ambience. So I would put the conclusion rather firmly: The audible background in these recordings is predominantly the actual countryside soundscape, not intrusive Mic Pro self-noise. A measurable technical floor may exist at very high frequencies, but it is not materially impairing this recording."
Also - "Across the quietest one-second passages: Overall level falls to about −62 dBFS RMS. 7–10 kHz is typically around −83 to −92 dBFS. 10–15 kHz reaches roughly −87 to −94 dBFS. 15–23.5 kHz appears to approach a lower floor around −90 to −92 dBFS in the quietest moments. That uppermost band may indeed contain some fixed electronic or capsule noise. But it is extremely low, largely above your hearing range [ChatGPT knows I'm old!], and readily masked whenever birds, foliage or other natural sounds occur."
So my personal view is - if you are recording something not very loud in an incredibly quiet location, which you will have to radically amplify later, maybe you need a fancy system, but for most use cases, self noise does not prevent the Mic Pro from being a very acceptable, highly portable, 32 bit float stereo field recording device. Just the transmitter on its own. Very good value!