I have some ambient noise recordings and am uncertain if the lower SPLs represent true low noise levels in the environment, or are perhaps due to the noise floor of the instrument itself.
I have plotted the third octave levels of an ambient noise recording, but am noticing that the minimum sound pressure level values increase at high frequencies where I don't expect them to. I suspect that this is a reflection of the sensitivity of my instrument, rather than a true representation of ambient noise in the environment.
I have seen some examples in the literature (see attached) of plotting the "self noise" of an instrument on top of this, however I am uncertain how to get these values across the frequency range of my instrument. How do I determine what this self noise (or 'noise floor') is, so I can plot it atop mine too? I want to get this across the spectrum of the recording range of an acoustic monitoring instrument.
EDIT: Device is a SoundTrap, so I cannot disassemble the recording chain.