Headphones are actually a fair bit less critical than speakers... uncorrelated white noise disappears somewhere around or a tad under +20 dB SPL, getting lost among our ears' internal racket (blood flow and such; it's even worse for in-ears). The threshold for speaker playback is lower only because those aren't literally strapped to our head, so a location of sound is possible by evaluating correlation between ears while potentially using head movements as well... AFAIK it's about +4 dB SPL.
So this one might get me the stupid question of the week award or something... but anyway: We all know hearing threshold curves, which are taken using narrow bandwidth tones AFAIK. What do they mean for minimum detectable white noise level though? How low typically is it? Are there any studies...
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It's still a
subwoofer. It would generally sport a lowpass somewhere. Say we've got an effective bandwidth of 200 Hz to be generous, then noise would already be down by 20 dB over the full 20 kHz. The way our hearing threshold is going up down there (not to mention how hard it is to get rid of low-frequency ambient noise), I doubt what remains would be audible.
Mind you, we've had a guy cursing his Genelec subwoofer here because the driver's breakup modes at a few kHz made internal Class D amplifier noise rather audible. He ultimately got a revised plate amp from Genelec, then the pillow in front of the driver could go.
I can't delete the thread because of some forum rules, so I'm just deleting the content
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This illustrates one point - it's all fine and dandy if the DAC is capable of such a dynamic range, but what if the limit is the power amplifier(s) instead? The kind of brute typically used for subs often is a bit rustic in the dynamic range department and might top out at around 105 dB(A).
BTW, a 170 dB dynamic range for an audio DAC is
insane - any analog stage you'd want to get that through would have to sport mic preamp level input noise and almost +/- 70 V power supply rails at the same time, even when only asking for unity gain (which isn't the most useful).