Comment by gwbas1c
7 years ago
When I casually researched the upper limit of human hearing, I came across something that mentioned that some people can detect lowpass filtering up to 27khz.
That's less than half an octave over the "traditional" 20khz limit. Even the 20khz limit is more of an average then a strict biological limit.
It also means that a sampling rate somewhere at 54khz is the "ideal" limit when trying to pick a sampling frequency that is completely transparent to everyone.
This is less than half an octave higher than the traditional 44.1khz rate, just 22% more data.
That's the thing that really drives me nuts about high sampling rates. The minute improvement really only needs a very slight boost in sampling rates, not 96khz or higher.
I've been in an internet argument among very serious digital audio experts (such as from Bell Labs) where the consensus reached was this: for properly done audio export as a final stage to be heard by the most critical listeners, and by properly done I mean the output is dithered and not simply truncated and everything else is done properly:
20, possibly 22 bit, and 60 to 80K.
Given that people screw that up by failing to dither to fixed point formats, you could push it to 24 bit, which is a generally supported word length. Since multipliers of common lower sample rates (44.1 and 48) give us 96K, that is also a good 'extra padding' to be certain of never encountering an issue.
I'm with Dan Lavry w.r.t 192K being unnecessary. Done properly, 96K gets everything, including extreme phenomena or artificial sound (for instance, I have a Farfisa organ that's capable of producing reedy thin sounds of extraordinary clarity, from simple electric tone generator circuits). I use 24/96 for my music stream recordings, while also streaming to YouTube at a much lower quality.
> When I casually researched the upper limit of human hearing, I came across something that mentioned that some people can detect lowpass filtering up to 27khz.
Link?
I'd want to know (a) if it was an analog or digital filter, (b) if the >20kHz signal intensity was normal/plausible and (c) how they ensured that the playback system wasn't generating intermodulation distortion products.
https://en.wikipedia.org/wiki/Hearing_range#Humans
Thanks. It's wikipedia but there's actually some good stuff there. The important link from that page seems to be:
https://asa.scitation.org/doi/full/10.1121/1.2761883
A decade has passed and it would be interesting to know how many people have reproduced the results detailed in the abstract. I gave it a quick read and at first glance it looks like an impressive experiment:
Hearing thresholds for pure tones between 16 and 30kHz were measured by an adaptive method. The maximum presentation level at the entrance of the outer ear was about 110dB SPL. To prevent the listeners from detecting subharmonic distortions in the lower frequencies, pink noise was presented as a masker. Even at 28kHz, threshold values were obtained from 3 out of 32 ears. No thresholds were obtained for 30kHz tone. Between 20 and 28kHz, the threshold tended to increase rather gradually, whereas it increased abruptly between 16 and 20kHz.