AnalogSteph
Major Contributor
I mean, it shouldn't be arbitrarily hard to get a good approximation of the noise floor... 0.3 µV(A) is "only" -128.2 dBu(A), which I imagine should be well within reach of at least some of the mic preamps you've got floating around. Even more so if you treat the stereo output as a balanced one with 3 dB higher noise and run that directly into the pre with a TRS --> XLR cable. (Yes, that might miss some common-mode noise, but we are not after the details at this point. Also, who cares if you need so much gain that the input clips before 50 mV, just as long as you are aware how much total system gain is. You are basically looking at the noise with a magnifying glass. Your measurement system does not need to have as much dynamic range as the output at all for this.)
Are you specifically going for a gain setting / volume combo on the L30 that gives 50 mV out with 2 V in, or just testing with volume turned down and an open (/shorted) input?
(If you need to do the math manually, here's a quick reminder that my RMS summing/unsumming calculator exists...)
Either way, even -96 dB ref. 50 mV or ~0.8 µV would still be as good as you'll ever need. That's something like -122 dBV, so should be <+20 dB SPL with any IEM in existence. Anything even better is really just showing off. But it should be reproducible if claimed, of course. We are looking for a unity gain stage with an equivalent flat input noise density of 2.75 nV/√(Hz). it's certainly not impossible if an OPA1612 (1.1 nV/√(Hz)) is involved.
Are you specifically going for a gain setting / volume combo on the L30 that gives 50 mV out with 2 V in, or just testing with volume turned down and an open (/shorted) input?
(If you need to do the math manually, here's a quick reminder that my RMS summing/unsumming calculator exists...)
The thing technically has an unbalanced output. I would make sure the measurement setup is 100% devoid of ground loops before making any such assumptions.
Either way, even -96 dB ref. 50 mV or ~0.8 µV would still be as good as you'll ever need. That's something like -122 dBV, so should be <+20 dB SPL with any IEM in existence. Anything even better is really just showing off. But it should be reproducible if claimed, of course. We are looking for a unity gain stage with an equivalent flat input noise density of 2.75 nV/√(Hz). it's certainly not impossible if an OPA1612 (1.1 nV/√(Hz)) is involved.
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