Let's assume a perfect source that produces constant background noise / hiss that is audible with certain headphones. The noise is constant and does not vary with volume. The source is also able to properly drive high impedance, low sensitivity headphones. Which characteristic of headphones will make them less prone to reflect that hissing audibly: sensitivity or impedance? I know that a low sensitivity, high impedance combo is the best, but am curious to learn which parameter has more effect on making the noise signal too weak for a pair of headphones to reproduce it.
As an example, which one of these headphones would be more opaque to the mentioned hiss:
A: 400ohm, 112dB/mW
B: 16ohm, 95dB/mW
C: 64ohm, 102dB/mW
B. Because it has lowest sensitivity in dB/V. And in your example noise always has the same voltage.
You can translate dB/mW to dB/V here - https://reference-audio-analyzer.pro/en/dbv-dbmw.php
You might consider an inline attenuator (volume control) or a headphone amplifier (with a volume control so it can be used as an attenuator).