Benchmark, being the heavily embedded in science and engineering sorts that they are, publish very useful application notes and system calculators on their website, this being one of them:
Will my audio system produce audible noise? Will my audio system produce audible distortion? How will my audio components work together as a system? How loud will my audio system play? Use Benchmark's online audio calculators to find answers! If we know the output power of an amplifier, as well...
benchmarkmedia.com
The audibility calculator does make some assumptions about hearing, and to be fair, Amir makes similar assumptions when discussing whether noise and distortion
might possibly be audible on measured equipment. The assumptions are that any noise/distortion above 0 dB SPL is audible, even if the peak output SPL is around 110 - 120 dB. This takes into account the absolute perception range of human hearing, however it doesn't account for the effects of masking.
If you're outside in a hurricane, you're not going to detect the sound of a pin dropping.
Masking is complex and I need to do some further research, but with a 30 - 40 dB(A) noisefloor in my listening room depending on time of day, 80-85 dB(A) is more than adequate for me to enjoy a listening session without background noise distraction, which begs me to ask the question, how good a SINAD do we
really need such that noise and distortion are inaudible relative to the music?
The ~110 dB or better SINAD yardstick unequivocally guarantees audible transparency, but where is the real threshold beyond which improvement is
measurable, yet still
inaudible, even to the most golden-eared?