Shouldn't we upgrade the 20-20 audible range ?!

[lashto]

There was recently a thread/test about audible DAC/filter differences and 'everyone' expressed serious doubts that the tester was able to hear above 20kHz. So I did a short check to see if that is so rare/incredible. And surprise: it is not!

Ultrasound: Hearing thresholds for pure tones above 16kHz (includes a short metastudy and a test). Quick resume (from Table1 in the study):

• 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.

Infrasound: Hearing at Low and Infrasonic Frequencies (pretty large metastudy). Quick resume (see Table3): if we keep the same 100dB limit, the infrasound audible threashold is actually ~8Hz.

Quick & clear conclusion: the audible range is actually 8Hz - 28kHz (at the fairly ok level of 100dB).

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 some 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 between ~ 1Hz and 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 ~10 years ago, Apple came up with retina-screens at 300 PPI and declared it to be the absolute 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 (again) for a long time it was considered that ~2000 DPI is "more than enough for everyone". Another round of controversy and nowadays professional gamer mice are at 10000+ DPI and the consumer ones at 2000+ too.

So, why are we in the audio world supossed to be happy with that seriously 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.
If reading is not your cup of tea, try a BBC podcast featuring those scientists:

Nature's secret, they believe, isn't the sound you can hear, it's the high frequencies you can't hear.

Or check some hypersonic art: A Study about Emotional Digital Art using Hypersonic Effect

And yes, live orchestras do go above 20kHz, some instruments even go above 100kHz: There's Life Above 20 Kilohertz:

At 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

and

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
If you do not like reading looong posts, you may enjoy someone singing it for you

 

[krabapple]

There was recently a thread/test about audible DAC/filter differences and 'everyone' expressed serious doubts that the tester was able to hear above 20kHz. So I did a short check to see if that is so rare/incredible. And surprise: it is not!

sigh. This again?

Ultrasound: Hearing thresholds for pure tones above 16kHz (includes a short metastudy and a test). Quick resume (see Table1):

What's heard with 'pure tones' is not necessarily translatable to normal music listening. Nor were the test conditions remotely akin to normal listening. This was investigation into what was *possible* for humans to hear, not into what they do hear , routinely.

• Test setup: 32 young ears tested, 19-25 years old. Max allowed/tested level ~100dB SPL.

Which is quite young and quite loud.

• 29 of 32 heard 20 kHz .. some at the very low level of 66dB!

20 Hz is within the conventionally accepted audible range.

• 16 (50%) heard 24 kHz.

....when the playback level of the pure tone in the setup shown above was at least 91.9dB

• 3 (9%) heard 28 kHz.

..when the playback level of the pure tone in the setup shown above was at least 101.3 dB

You seriously want to hang your argument that ultrahigh frequencies matter for home audio listening,on this?

Infrasound: Hearing at Low and Infrasonic Frequencies (pretty large metastudy). Quick resume (see Table3): if we keep the same 100dB limit, the infrasound audible threashold is actually ~8Hz.

The 'low' frequencies they refer to are in the audible range (20-200 Hz) and the infrasound below that can be 'perceived' if 'level is sufficiently high'. There are plenty of audiophiles who already fetishize subwoofer output below 20 Hz, so what exactly is new here?

Quick & clear conclusion: at the fairly ok level of 100dB, the audible range is actually 8Hz - 28kHz.

100dB is 'fairly ok'? Not for anything more than a short time, if you want to keep your hearing intact.

 

[kemmler3D]

If you can find me a piece of music, or a movie, or really any listening content at all that includes frequencies above 20Khz @ >90dB where there is also content at >90dB at or below 5khz, I will agree that we should start considering "ultrasound" performance more carefully.

I'm pretty sure none or virtually none exists.

Why not? Many reasons:

Most mics are not designed to pick up ultrasound and most studio equipment is not designed to work on ultrasound. Most musical instruments do not produce appreciable amounts of ultrasound in the first place, either.

And, even when ultrasound is present, lower harmonics will tend to mask it, since even among those who CAN hear that high up, hearing is less sensitive.

This is sort of like saying TV screens should produce near infrared or ultraviolet for the small portion of the population that can sorta kinda see it. From a certain over-engineering perspective, yes. From a practical perspective, no, lol.

 

[DVDdoug]

I wonder if the results are repeatable. Of course people do vary... I think 20kHz is the "normal" limit for young people with normal hearing. I'm in my 60s and I can't hear to 20kHz.

And if someone thinks that is "too much" or "unnecessary".

The highest frequencies in normal program material are weak harmonics and our hearing is less-sensitive to high (and low) frequencies. If you are listening to a 100dB+ rock band, any ultrasonics are much weaker and you're probably already getting a temporary threshold shift (temporary hearing loss)... Hopefully temporary.

The people working on lossy compression have found that the highest-audible frequencies are masked by not-as-high frequencies in the context of normal music. Lossy compression mostly works by throwing away sounds that are masked (not just the highs). Most people can't tell if the highest-highs are missing. If you hear an MP3 compression artifact you are probably hearing something else. I'm not saying you should eliminate those frequencies (without good reason) but I'd say, "probably unnecessary".

Also higher frequencies are attenuated in the air. I think I've read that there's a measurable/audible difference between the front and back of a concert hall (and that's in the "traditional" 20Khz range).

I don't think 8Hz is considered "sound". You might feel it in your ears or body but it's not sound and not a normal part of music. You can feel air pressure in your ears down to 0Hz but nobody is trying to simulate going up & down in an airplane in their home theater.

The lowest note on a standard bass guitar is about 32Hz. That's low enough for bass you can feel in your body if it's strong enough. (Pipe organs can go down to 16 Hz.) The lowest note on a piano is about 27Hz but I don't think we hear it.... The harmonics are louder than the fundamental and I'm pretty sure that's what we hear.

Digital audio can go down to 0Hz (with the upper limit determined by sample rate) and it's not hard to make an amplifier that goes from DC to over 100kHz. Speakers (and microphones) are the big limiting factor. Often subsonics and ultrasonics are filtered out because they can cause more trouble than they are worth.

 

[Brian Hall]

There was recently a thread/test about audible DAC/filter differences and 'everyone' expressed serious doubts that the tester was able to hear above 20kHz. So I did a short check to see if that is so rare/incredible. And surprise: it is not!

Ultrasound: Hearing thresholds for pure tones above 16kHz (includes a short metastudy and a test). Quick resume (see 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.

Infrasound: Hearing at Low and Infrasonic Frequencies (pretty large metastudy). Quick resume (see Table3): if we keep the same 100dB limit, the infrasound audible threashold is actually ~8Hz.

Quick & clear conclusion: at the fairly ok level of 100dB, the audible range is actually 8Hz - 28kHz.

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 some extra kHz. And if we do a bit of rounding-up like good engineers do (to make sure that we cover everything), 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 range). 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 between ~1Hz and ~60kHz.

And if someone thinks that 3-30 is "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 ~10 years ago, Apple came up with retina-screens at 300 PPI and declared it to be the absolute 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 (again) for a long time it was considered that ~2000 DPI is "more than enough for everyone". Another round of 'controversy' and nowadays professional gamer mice are at 10000+ DPI and pretty much any consumer one is at 2000+ too.

So, why are we in the audio world supossed to be happy with that seriously truncated 20-20 audible range?!

They heard noise. No useful musical information exists at those high frequencies. Reproducing them is worse than useless.

 

[Duke]

The lowest note on a standard bass guitar is about 32Hz. That's low enough for bass you can feel in your body if it's strong enough. (Pipe organs can go down to 16 Hz.) The lowest note on a piano is about 27Hz but I don't think we hear it.... The harmonics are louder than the fundamental and I'm pretty sure that's what we hear.

The fundamental of low-B (31 Hz) on a bass guitar is normally quite low in level compared to the overtones. I am only aware of ONE bass guitar cab manufacturer (Acme) who builds cabs that actually deliver a strong first overtone of low-B. None of my bass cabs do because the penalty in weight and size is simply too great; my target is normally the 62-Hz first overtone of low-B.

Along similar lines, not only is the 27 Hz fundamental of low-A on a piano not (normally) audible, neither is its 54 Hz first overtone! In fact the lowest tone produced by a piano that is normally audible is, once again, the 62-Hz first overtone of low-B. I learned this when researching "where the goal posts are" for a cab intended for use with an electric piano.

The ear/brain system detects the overtone sequences (in particular the overtone spacing) and infers the pitch of the fundamental even when it's not actually audible. It's almost like whatever engineered human hearing made it work better than its raw specs say it should: I'm friends with a luthier who makes electric subcontrabasses with tunings south of 20 Hz, and we can't begin to hear those fundamentals but we can still hear the notes because we can detect the overtone sequences.

Edit: I should have specified that low-B is the lowest note on a typical 5-string bass; most 4-string basses are tuned to low-E (41 Hz fundamental), thanks @krabapple. There are of course other tunings; for a while I made a cab tuned for the 46 Hz first overtone of low-F#.

 

[lashto]

sigh...

without going into any details, this is the kind of viewpoint/attitude that I just cannot understand.

Pretty much every other domain is progressing, going up, going for more etc...
Like in the examples I posted: the vision-guys more than doubled their ranges and minimum requirements this century, the touch-guys did the same ... almost every other tech domain is advancing at moore-law pace.

Why is everyone in audio so complacent and 'happy' with that 50 years old 20-20 range?! Which isn't even the ear's range, it's just a tech limitation from 50 years ago: i.e. that's what Philips/Sony engineers were able to (practically) cover during the 70s-80s.

So what if most people (presumably) cannot hear over 20kHz? Most people cannot distinguish 300 PPI either. But the vision/display guys are building 600+ PPI. Because they want ... because they can ... because progress...

Isn't there anyone in audio who wants to join the 21st century?
And if so, why is that? Is it because audio is actually dominated by old-farts (like most of us) who can barely hear 15kHz? Is it because young people are actually unaware that they are getting a truncated version of what they can actually hear? Is it because lack of money/funds? Lack of interest? Lack of imagination? Lack of competence?
Lack of ... what exactly?

 

[kemmler3D]

a truncated version of what they can actually hear?

Can hear? Maybe. Will hear?

Is it because lack of money/funds? Lack of interest? Lack of imagination?
Lack of ... what exactly?

It's a lack of audible content above 20khz. If you play someone a square wave (pretty much a worst-case for this kind of thing) band limited to 20khz or 100khz it probably won't sound any different, even to these kids with pristine ears. I'd be interested to know if it did, but I'm fairly sure due to masking effects, it won't.

And a lot of gear is capable of 100khz or more if you look for it. It's just that you'll need to add a supertweeter to your speakers, but nobody is stopping you. Digital audio goes down to 0hz no problem and you can buy subs to hit single digits if you want.

Anecdote on audibility of this stuff: my LCD-XCs go below 20hz pretty well. They also have really low distortion... down around 15hz doesn't sound like anything to me. A lot of times what we hear from sub-20hz tones is actually THD at 2-3x the fundamental frequency. If you are able to get JUST a sub-20hz tone going, with no distortion, it can be somewhat disconcerting.

 

[Brian Hall]

Why is everyone in audio so complacent and 'happy' with that 50 years old 20-20 range?! Which isn't even the ear's range, it's just a tech limitation from 50 years ago: i.e. that's what Philips/Sony engineers were able to (practically) cover during the 70s-80s.

It covers the human ear's useful range. Those high frequencies above 20khz that only very young people can hear are not pleasant sounds. They are actually used as a deterrent to keep teenagers from loitering around certain areas. They can hear those unpleasant irritating high frequency sounds and it drives them away.

Why do you think there is any value in having our systems be able to reproduce those frequencies?

As for the bass tones below 20hz, again, not audible to us. What benefit do you think they would add?

 

[MRC01]

Most adults cannot hear 20 kHz, though many with healthy ears, and depending on their age, can hear 15 kHz.
Most adults can hear lower than 20 Hz, and we don't lose low frequency perception with age like we do high frequencies.
So a more realistic range of human hearing might be 16 Hz to 16 kHz. That is still optimistic. But nothing says it has to be a range of 1:1000. It could for example be 17 Hz to 15 kHz.

However, no definition can be perfect because human perception varies by age and by individual. The best approach would be to study randomly selected people from the population and set the range at what 85% of them can hear. But even that will depend on how old they are, where they live, their occupation, etc.

 

[MRC01]

... As for the bass tones below 20hz, again, not audible to us. What benefit do you think they would add?

Most people can hear below 20 Hz. However one could argue speakers don't need it because very little music has energy in that range.

 

[krabapple]

The title of this thread is misleading btw. It isn't about upgrading the 20Hz-20kHz range (which could be a legitimate goal, though there's little to do there other than in the realm of transducers and room acoustics) . It's about extending performance to frequencies outside that range. Which already happens, depending on what gear you are talking about.

The fundamental of low-B (31 Hz) on a bass guitar is normally quite low in level compared to the overtones. I am only aware of ONE bass guitar cab manufacturer (Acme) who builds cabs that actually deliver a strong first overtone of low-B. None of my bass cabs do because the penalty in weight and size is simply too great; my target is normally the 62-Hz first overtone of low-B.

To be clear, you're talking about a 5-string bass guitar here. (A typical bass has 4 strings and its lowest note is the E fundamental of 40Hz.)

 

[krabapple]

without going into any details, this is the kind of viewpoint/attitude that I just cannot understand.

Pretty much every other domain is progressing, going up, going for more etc...

Which can be useful or a pointless reflex, depending

Like in the examples I posted: the vision-guys more than doubled their ranges and minimum requirements this century, the touch-guys did the same ... almost every other tech domain is advancing at moore-law pace.

Just because vision and smell and hearing and touch are senses, doesn't make them analogous. The different sensory reproduction technologies proceeded at different paces because they present different challenges. Audio turned out to be one of the easier ones to 'perfect'.

Why is everyone in audio so complacent and 'happy' with that 50 years old 20-20 range?! Which isn't even the ear's range, it's just a tech limitation from 50 years ago: i.e. that's what Philips/Sony engineers were able to (practically) cover during the 70s-80s.

So what if most people (presumably) cannot hear over 20kHz? Most people cannot distinguish 300 PPI either. But the vision/display guys are building 600+ PPI. Because they want ... because they can ... because progress...

because marketing?

 

[DVDdoug]

Another Floyd Toole quote:

"I have dedicated my work to solving the "10dB" problems first, the 5dB problems next so on."

To be clear, you're talking about a 5-string bass guitar here. (A typical bass has 4 strings and its lowest note is the E fundamental of 40Hz.)

Right!!! ...Faulty memory! Corrected above. (I did say "standard" bass guitar and I just remembered wrong.)

 

[sigbergaudio]

without going into any details, this is the kind of viewpoint/attitude that I just cannot understand.

Pretty much every other domain is progressing, going up, going for more etc...
Like in the examples I posted: the vision-guys more than doubled their ranges and minimum requirements this century, the touch-guys did the same ... almost every other tech domain is advancing at moore-law pace.

Why is everyone in audio so complacent and 'happy' with that 50 years old 20-20 range?! Which isn't even the ear's range, it's just a tech limitation from 50 years ago: i.e. that's what Philips/Sony engineers were able to (practically) cover during the 70s-80s.

So what if most people (presumably) cannot hear over 20kHz? Most people cannot distinguish 300 PPI either. But the vision/display guys are building 600+ PPI. Because they want ... because they can ... because progress...

Isn't there anyone in audio who wants to join the 21st century?
And if so, why is that? Is it because audio is actually dominated by old-farts (like most of us) who can barely hear 15kHz? Is it because young people are actually unaware that they are getting a truncated version of what they can actually hear? Is it because lack of money/funds? Lack of interest? Lack of imagination? Lack of competence?
Lack of ... what exactly?

You are not understanding what you are reading in those studies and/or how it relates to a real world situation where you are playing back music through an audio system. You will not be able to hear any content over 20khz, period.

You talk about 24-28khz at 100dB. If you had 24khz content in typical music, where 24khz is played back at 100dB, the level in the bass would be maybe 120dB. Picture yourself at the very front row of an outdoors heavy metal concert. This is the type of sound level we are talking about. Do you honestly thing you'd be able to distinguish sounds above 20khz (or even 10khz) in such a situation, when people can barely hear it with headphones on in a laboratory situation with no other sound present but that single 24khz sine wave?

 

[Wanman]

The following is my understanding as of this point in time. It is subject to revision in light of new information:
Pretty much all measurements of what humans can hear are related to the "average ear." That means things like Limits of Audibility, the Absolute Limit of Hearing, and the range of audible frequencies, are all estimates of values for the average ear (i.e. estimates of the center of a bell curve). None of them are hard limits, except maybe the limit imposed by the level of background thermal noise in a room. Not that a noise floor is a hard limit either. There may be some ability to detect/hear signals buried a little below a noise floor (noise floor is an average too since it is always to some extent fluctuating randomly).

 

[Oddball]

Given the age, I could care less for above 14-15kz level, with a notion that that will inevitably get reduced over time.

In the HT world, few people are chasing sub-bass that is present in some tracks, and could be extracted from others. Example would be the opening of Edge or Tomorrow where there is sub 10hz bass. One will not necessarily hear it but will feel it which can be positively confirmed with the sub woofers moving. It is acquired taste and some people actually feel nauseous at these frequencies. You would also need to have an army of really large subs to get this 10hz signal to 100dB, which is extremely loud overall, but in this range would actually need to be probably even "louder" aka more tactile to feel the full impact.

Most mainstream subs (even the "big ones") don't go below 15hz extension for a reason. It does cover 20hz at decent level and then rolls off. Even at 20hz, it is usual to have -10dB or more compared to the max sub output in the higher range. Also, even in HT, a lot of movies are stripped of the low bass info and bottom out at some 30hz (which can be restored by freeware software at your own risk). IMO absolutely no need to extend the range and especially not in the low end. But would be useful to have the full 20hz extension for HT.

 

[Cbdb2]

So, why are we in the audio world supossed to be happy with that seriously truncated 20-20 audible range?!

Because all the music is there, seriously. The rest is noise.

 

[Keith_W]

I think close to 100% of people on ASR would agree that anything > 20kHz is inaudible.

But infrasound is another matter. We may not be able to hear it, but we can certainly feel it - if it is loud enough.

 

[Timcognito]

Do many acoustic instruments produce sound above 20 KHz? Flute or Piccolo? Cymbals or Bells?