There was recently a thread/test about audible DAC/filter differences and 'everyone' had doubts that the tester was able to hear above 20kHz. So I did a short check to see if that is really so rare and incredible. On short: it is not!
Ultrasound hearing range:
Hearing thresholds for pure tones above 16kHz. Quick resume (from Table1):
Hearing at Low and Infrasonic Frequencies. Quick resume (Table3): at 100dB SPL the audible threashold is ~8Hz.
Quick & pretty clear conclusion: the audible range is actually 8Hz - 28kHz.
(at the fairly ok level of 100dB SPL)
But ASR measures distortion/etc at 114dB and at that level the infrasound threshold is 4-5Hz. No data for ultrasound but probably fair to assume a few extra kHz. If we do a bit of rounding-up, like good engineers do to make sure that everything is covered, the range becomes 3Hz-30kHz. That sounds like the absolute bare minimum to me!
And maybe we can stop building devices like shrewd salesmen (i.e. barely cover the minimum required). And start building them like good engineers (i.e. clean to double the specs, just to be sure).
In that case, we should have audio devices and recordings that are 100% clean approx 1Hz-60kHz.
And if someone thinks that 3-30 or 1-60 are "too much" or "unnecessary", here are two examples from other fields/senses:
- vision. For a long time and based on various studies, the 'consensus' was that ~150-200 PPI resolution was "more than enough for everyone". But then Apple came up with retina-screens at 300 PPI and declared it to be the minimum required. After a bit of controversy, nowadays we have smartphones at 500+ PPI.
- touch. In the gaming community the mouse sensitivity/speed is very important and for a long time it was considered that ~2000 DPI is "more than enough for everyone". Another round of controversy and nowadays gamer-mice are at 10000+ DPI and consumer ones at 2000+ too.
So, why are we in the audio world supossed to be happy with the heavily truncated 20-20 'audible' range?!
P.S.
a 'bit' of extra science
Studies (many hundreds) about the effects of inaudible infra & ultra-sounds on the human body: here and here.
An AES meta-study on ultrasonics in music: A Meta-Analysis of High Resolution AudioPerceptual Evaluation:
Living cells do react to both infra- and ultra-sounds over the entire 1Hz-1MHz range, with some interesting hotspots in the 10-150kHz area.
The Hypersonic Effect detailed in 30+ studies from various Japanese scientists/universities as summarized by AES. Or as a BBC podcast:
And maybe you will enjoy some hypersonic art: A Study about Emotional Digital Art using Hypersonic Effect.
Live orchestras do go above 20kHz, some instruments even go above 100kHz: There's Life Above 20 Kilohertz:
P.S.2
someone else posted a nice list of (technical) reasons why 44kHz recording/playback is actually not enough.
P.S.3
If you do not like reading looong posts, you may enjoy someone singing it for you
Ultrasound hearing range:
Hearing thresholds for pure tones above 16kHz. Quick resume (from Table1):
- Test setup: 32 young ears tested, 19-25 years old. Max allowed/tested level ~100dB SPL.
- 29 of 32 heard 20 kHz .. some at the very low level of 66dB!
- 16 (50%) heard 24 kHz.
- 3 (9%) heard 28 kHz.
Hearing at Low and Infrasonic Frequencies. Quick resume (Table3): at 100dB SPL the audible threashold is ~8Hz.
Quick & pretty clear conclusion: the audible range is actually 8Hz - 28kHz.
(at the fairly ok level of 100dB SPL)
But ASR measures distortion/etc at 114dB and at that level the infrasound threshold is 4-5Hz. No data for ultrasound but probably fair to assume a few extra kHz. If we do a bit of rounding-up, like good engineers do to make sure that everything is covered, the range becomes 3Hz-30kHz. That sounds like the absolute bare minimum to me!
And maybe we can stop building devices like shrewd salesmen (i.e. barely cover the minimum required). And start building them like good engineers (i.e. clean to double the specs, just to be sure).
In that case, we should have audio devices and recordings that are 100% clean approx 1Hz-60kHz.
And if someone thinks that 3-30 or 1-60 are "too much" or "unnecessary", here are two examples from other fields/senses:
- vision. For a long time and based on various studies, the 'consensus' was that ~150-200 PPI resolution was "more than enough for everyone". But then Apple came up with retina-screens at 300 PPI and declared it to be the minimum required. After a bit of controversy, nowadays we have smartphones at 500+ PPI.
- touch. In the gaming community the mouse sensitivity/speed is very important and for a long time it was considered that ~2000 DPI is "more than enough for everyone". Another round of controversy and nowadays gamer-mice are at 10000+ DPI and consumer ones at 2000+ too.
So, why are we in the audio world supossed to be happy with the heavily truncated 20-20 'audible' range?!
P.S.
a 'bit' of extra science
Studies (many hundreds) about the effects of inaudible infra & ultra-sounds on the human body: here and here.
An AES meta-study on ultrasonics in music: A Meta-Analysis of High Resolution AudioPerceptual Evaluation:
The overall conclusion is that the perceived fidelity of an audio recording and playback chain can be affected by operating beyond conventional levels.
Living cells do react to both infra- and ultra-sounds over the entire 1Hz-1MHz range, with some interesting hotspots in the 10-150kHz area.
The Hypersonic Effect detailed in 30+ studies from various Japanese scientists/universities as summarized by AES. Or as a BBC podcast:
Apparently, those 'inaudible' 20-120kHz sounds are still perceived and do make a difference in listeners' mood an level of enjoyment. Their presence/absence is also visible in EEG measurements.Nature's secret, they believe, isn't the sound you can hear, it's the high frequencies you can't hear.
And maybe you will enjoy some hypersonic art: A Study about Emotional Digital Art using Hypersonic Effect.
Live orchestras do go above 20kHz, some instruments even go above 100kHz: There's Life Above 20 Kilohertz:
andAt least one member of each instrument family (strings, woodwinds, brass and percussion) produces energy to 40 kHz or above, and the spectra of some instruments reach this work’s measurement limit of 102.4 kHz. Harmonics of muted trumpet extend to 80 kHz; violin and oboe, to above 40 kHz; and a cymbal crash was still strong at 100 kHz
Given the existence of musical-instrument energy above 20 kilohertz, it is natural to ask whether the energy matters to human perception or music recording ... experimenters found that the listeners' EEGs and their subjective ratings of the sound quality were affected by whether this "ultra-tweeter" was on or off, even though the listeners explicitly denied that the reproduced sound was affected by the ultra-tweeter.
P.S.2
someone else posted a nice list of (technical) reasons why 44kHz recording/playback is actually not enough.
P.S.3
If you do not like reading looong posts, you may enjoy someone singing it for you
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