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

[Geert]

the human body actually has lots of specialized receptors for sound/vibration, e.g. People Hear with Their Skin as well as Their Ears.

What this article explains is how feeling air puffs that go along with certain letters ("p," "b", "t", "k"...) can support the identification of them. The other articles you linked dicuss another feeling, namely pressure. So:

1. The skin doesn't hear sound, it feels air flow or pressure. Hearing and feeling are different sensations. And air flow and pressure or not sound. So no, we shouldn't extend the audible range with frequency ranges related to others senses. Otherwise we might as well add the frequencies of light to it to include eye sight, which also supports identification of sound.
2. The skin doesn't identify sounds, it only supports what we hear for sounds that provide a clue via puffs of air.

Just like in that other distaster topic of yours, the missing 15kHz fundamental thing, you're abusing scientific work to dress up your fantasies.

 

[dlaloum]

"Theory" in the sense of "speculation" or "conjecture" rather than the scientific use of the word...

There was a test done with the participants at an AES convention some decades back... it demonstrated that at least a small minority could indeed differentiate between recordings with content above 20KHz and recordings without....

You would need to seek it out.... but there is reasonable scientific evidence that some people can indeed hear (or perhaps more accurately "sense" ) beyond 20Khz

 

[sonitus mirus]

There was a test done with the participants at an AES convention some decades back... it demonstrated that at least a small minority could indeed differentiate between recordings with content above 20KHz and recordings without....

You would need to seek it out.... but there is reasonable scientific evidence that some people can indeed hear (or perhaps more accurately "sense" ) beyond 20Khz

Unless this is about Oohashi’s somewhat famous and controversial 'hypersonic effect' experiments, which were full of flaws and never properly proven or repeated, the claim about people sensing sounds above 20 kHz doesn’t make much sense. Maybe very young people with perfect hearing could detect something at those frequencies, but there’s very little in the way of actual musical content at 20 kHz or higher, and certainly nothing that could be considered a musical note. Saying a small group of people at some event decades ago could hear these frequencies isn’t real evidence. It’s more of a vague anecdote than anything meaningful.

 

[Sal1950]

You would need to seek it out.... but there is reasonable scientific evidence that some people can indeed hear (or perhaps more accurately "sense" ) beyond 20Khz

Ah, in this case you would need to seek it out since your presenting it as evidence.
Also just being presented at the AES doen't prove the test wasn't flawed in some way.
And in all the decades since it's never been repeated?
Any scientific test with a controversial result would always get repeated, repeatedly.
I'm not buying it.

 

[MAB]

There was a test done with the participants at an AES convention some decades back... it demonstrated that at least a small minority could indeed differentiate between recordings with content above 20KHz and recordings without....

You would need to seek it out.... but there is reasonable scientific evidence that some people can indeed hear (or perhaps more accurately "sense" ) beyond 20Khz

Please see post #471 for the most recent clarification on this.

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

Glad you seem to enjoy mr Reiss and his work a bit more than this-japanese-fellow. Would you care to cite some of those "experts who do not"? Particlarly the one study which already debunked mr Reiss' meta .. and why not, everything else beyond-20-20. You'd have found some of them in comments...

www.audiosciencereview.com

There is in fact no reproducible or credible evidence. And the evidence, like studies on ultrasonic content with material that actually lacked ultrasonic, points the opposite direction. It's not like ultrasonic content, drivers, and measurement gear doesn't exist.

 

[dlaloum]

Unless this is about Oohashi’s somewhat famous and controversial 'hypersonic effect' experiments, which were full of flaws and never properly proven or repeated, the claim about people sensing sounds above 20 kHz doesn’t make much sense. Maybe very young people with perfect hearing could detect something at those frequencies, but there’s very little in the way of actual musical content at 20 kHz or higher, and certainly nothing that could be considered a musical note. Saying a small group of people at some event decades ago could hear these frequencies isn’t real evidence. It’s more of a vague anecdote than anything meaningful.

The contention is that some people can sense frequencies beyond 20kHz - there is enough evidence out there to state with confidence that this is indeed true.

Is the fact that you can sense (barely!) with statistical positive confidence - the presence of ultrasonics, make those ultrasonics in any way useful? no.

Anecdotally, I had a friend who worked in security / alarms, he used to install a lot of ultrasonic movement sensors.... which are typically tuned to frequencies up above 20kHz (21kHz to 23KHz are typical).

In setting up the alarms they had to manually adjust the frequency during the installation, which most installers do with an appropriate rig which includes mic, and electronics - my friend had the good luck (and hearing) of having the limit of his hearing be right at the required frequency.... so he and his team used to save a lot of time by having him listen for the ultrasonics as they raised the frequency.... they would raise it until he could no longer hear it, drop it back a smidge to where he could barely sense it, and that was it.... when measured with the "rig" it was 21 to 23kHz right where it needed to be.
Interestingly he continued to be able to do this until he retired and sold the business in his late 50's....

As I said, not useful for recordings, movies, music etc... but, yes I feel confident that some humans have a much wider frequency range of hearing than most of us do. (Natural variability is bound to guarantee this in any case!)

 

[dlaloum]

Ah, in this case you would need to seek it out since your presenting it as evidence.
Also just being presented at the AES doen't prove the test wasn't flawed in some way.
And in all the decades since it's never been repeated?
Any scientific test with a controversial result would always get repeated, repeatedly.
I'm not buying it.

It wasn't presented at the AES, they did the test during an AES conference, and used the Audience as the test subjects.... Results were later published - but it was aiming only at a simple answer to "can you statistically detect a difference between track A and track B and track C" - traditional simple ABX
Most people could not - but a small minority could, with statistically significant consistency

 

[sonitus mirus]

The contention is that some people can sense frequencies beyond 20kHz - there is enough evidence out there to state with confidence that this is indeed true.

Is the fact that you can sense (barely!) with statistical positive confidence - the presence of ultrasonics, make those ultrasonics in any way useful? no.

Anecdotally, I had a friend who worked in security / alarms, he used to install a lot of ultrasonic movement sensors.... which are typically tuned to frequencies up above 20kHz (21kHz to 23KHz are typical).

In setting up the alarms they had to manually adjust the frequency during the installation, which most installers do with an appropriate rig which includes mic, and electronics - my friend had the good luck (and hearing) of having the limit of his hearing be right at the required frequency.... so he and his team used to save a lot of time by having him listen for the ultrasonics as they raised the frequency.... they would raise it until he could no longer hear it, drop it back a smidge to where he could barely sense it, and that was it.... when measured with the "rig" it was 21 to 23kHz right where it needed to be.
Interestingly he continued to be able to do this until he retired and sold the business in his late 50's....

As I said, not useful for recordings, movies, music etc... but, yes I feel confident that some humans have a much wider frequency range of hearing than most of us do. (Natural variability is bound to guarantee this in any case!)

Natural differences in hearing are well understood, and while some people might sense frequencies above 20kHz, it’s uncommon and hard to verify without proper testing. Your friend’s ability is interesting, but it’s tough to confirm scientifically. Even so, this kind of sensitivity doesn’t really matter for music or audio, as most equipment and recordings are designed for the 20Hz to 20kHz range, and frequencies beyond that don’t contribute meaningfully to the listening experience.

 

[boxerfan88]

I believe 20-20k is just some convenient range decided by someone in the past. It could have been 19-19k or 21-21k or 21-19k or whatever… We don’t have to hold on to it as if it’s some natural law.

Personally I think superb system performance in the 30-15k range is good enough to enjoy HiFi. Any superb performance wider than that is icing on a great cake.

 

[EJ3]

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):

• 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 range:
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:

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.
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:

and


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

Perhaps the AMP you are looking for (check out the frequency response):

• YAMAHA MX-10000​

• ¥ 800,000 (released in 1987)

Commentary​

A power amplifier developed by Yamaha to commemorate the 100th anniversary of its founding.

An HC (hyperbolic transformation) class A operation circuit is adopted in order to solve the weak point of class A operation circuit, which shifts to class AB operation during low impedance driving.
This hyperbolic conversion uses the characteristics of the collector current and base-emitter voltage of the transistor and consists of two dual transistors. Thus, even if the current exceeds twice the idling current, class A operation is maintained and linearity of input / output is maintained.
However, since the HC circuit has no gain, a power MOS FET and power current mirror output circuit are provided in the latter stage.

The output device is a 4-para push-pull power MOS FET with high-speed and high-current operation developed for the MX-10000.
In addition, in order to solve the large-scale heat generation problem of class A amplifier, a dual amplifier class A configuration using two SEPP amplifiers in one channel is adopted. In addition to the output stage for current amplification, a power buffer amplifier for supplying necessary power is mounted.
The power buffer contains Hi-f of Pc 200W, which boasts high performance as an output device for audio.TIt uses a power transistor and consists of 6 para push-pull.
In the dual amplifier Class A, since the ground is a non-current ground that only determines the ground potential, unstable elements of the amplifier due to current flowing in the ground are also eliminated.

The voltage amplifier for voltage amplification employs a class A operation circuit for all stages : dual FET differential input for the first stage, current mirror for the second stage, and emitter follower push-pull for the last stage.
The dual-FET differential input and current mirror enable low-distortion signal amplification with little loss. The emitter-follower push-pull enables low-impedance signal output. In addition, the voltage amplifier incorporates a floating power supply circuit, and the voltage corresponding to the amplitude of the input signal is fed to the first and second stages. Therefore, even if there is a transient input, the amplifier can be used with a margin without saturation. Thus, highly stable voltage amplification is obtained.

The power supply section includes a power MOS FET output stage equipped with an HC circuit, and Hi-f to eliminate mutual interference of signal systems fluctuated by large amplitude signals.TEach power supply to a power buffer that employs a power transistor uses an ICP system with independent current loops.
The power supply section is independent of the transformer. The power supply for the output stage and the + B and -B power supplies for the power buffer are independent from the transformer winding to the power supply circuit to form the current loop for the output stage and the power buffer respectively, thereby stabilizing the operation state of the transformer.
The output current is supplied from the + B power supply and -B power supply, and the output stage power supply is independent of the output current. Therefore, the power supply does not fluctuate even at large output, and the class A operation is supported from the power supply side.

In order to avoid the deterioration of sound quality caused by the interposition of speaker selector switch, only one stereo system is used as the speaker output.
In addition, by using only one system, the NFB loop is extended to the output terminal of the speaker with high stability, and the terminal from the power MOS FET output stage and the Hi-fTIt is equipped with a direct error collection amplifier that directly feeds back the signal from both terminals of the terminal from the power transistor and power buffer to correct distortion. It eliminates not only the slight distortion generated at the output stage but also the minute non-linear of the output coil and speaker relay.

Aiming to obtain high strength construction and electrical and mechanical ground potential, it is symmetrical construction on both sides, and high rigidity non-magnetic aluminum extruded material is used entirely for chassis / frame.
The front panel is 12 mm thick, the main chassis and frame is 5 mm thick, and the rear panel is 3 mm thick. The thickness of each member is changed in stages. Each member is firmly fixed with screws. It has characteristics unique to extruded materials that do not cause metal fatigue such as bending descent. Furthermore, acoustic tuning is applied taking into consideration the continuity of the strength distribution of each structural material. Thus, the chassis / frame has a high balance of organic structure that combines beauty and beauty.

A large 3-piece heat sink is used to dissipate heat from the 20 output elements used in the power stage.
The heat-radiating fins have a resonance dispersion type structure in which the length of each fin has a gradation structure with different base thicknesses, thereby dispersing the vibration mode peculiar to the heat sinker and eliminating the generation of modulation noise caused by squeal.
In addition, on the mounting side, a cork-spacer is inserted in the part where the heat radiation fin touches, and it is mounted rigidly on a high-rigidity chassis, and the heat sinker is part of the structure to prevent the occurrence of unnecessary resonance.

The 6-mm-diameter brass and gold-plated shaft connects the power stage amplifier circuit board and power supply circuit board to each other through a heat sinker, thereby eliminating the possibility of subtle errors in wiring processing and changes in characteristics caused by such errors.
In addition, OFC (oxygen-free copper) gold-plated bus bars are embedded in the power stage amplifier substrate, and a rigid method in which current flows through low impedance is adopted.
All electrical connections from the input to the output are gold-plated, including screws and washers.

The power transformer employs a toroidal type with low leakage flux, and is equipped with a large double toroidal transformer with a total weight of 15 kg. The transformer consists of two layers of two toroidal transformers for output stage and power buffer.
The inside of the shield case is filled with a filler to suppress the noise of the transformer.
In addition, taking advantage of the advantages of a toroidal power transformer with excellent coupling between the primary and secondary sides, a toroidal choke is separately inserted in the primary side to improve the rectification characteristics as a semi-choke input rectification. This prevents sudden fluctuations in AC voltage caused by the rush current when the power is turned on, and prevents mutual power interference between audio component devices during normal operation.
The Chemi-Con for smoothing uses constant magnification foil and high-quality audio aluminum electrolytic capacitors with excellent temperature stability and low current ripple.
The power MOS FET output stage has a capacity of 100,000 μ Fx2 and the power buffer amplifier has a capacity of 22000 μ Fx4, for a total capacity of 288000 μ F. It is also located in the center of the power amplifier for construction purposes, and a well-balanced power supply to the amplifiers of both LR channels.

A protection circuit is provided to prevent damage to the output elements and speakers due to short-circuit accidents.
The protection system eliminates the PC limiter, which tends to cause sound quality degradation for low impedance loads and capacitive loads, and uses a protection circuit system with a relay switch that cuts off output only when overcurrent or DC component is detected.

In addition to the power switch, a protection linked speaker switch is provided.
This allows you to turn the speaker output on and off while the output is in standby mode.

It is equipped with a dB scale logarithmic compression type peak level meter independent of LR to indicate the output power level to the speakers.
Instantaneous output wattage can be read at load levels of 8 Ω and 4 Ω.

The parts used use high-grade elements that have been carefully examined for sound quality.
We use polypropylene film capacitors and mica capacitors as in-circuit capacitors, metal-coated resistors and non-inductive wound resistors with copper leads as resistors, and hollow-dip OFC coils as output coils.

The input terminal uses a gold-plated brass machined pin jack with excellent corrosion resistance and contact properties.

The speaker output terminal uses a large, gold-plated screw type that is suitable for extremely thick cables.

The AC power cord uses a 10 mm diameter cable made of OFC wire, and polarity is indicated on the plug.

There is a dedicated cable connection terminal (transmit / receive) that enables the MX-10000 to be turned on / off in conjunction with the CX-10000 power on / off.
By providing transmission terminals in addition to receiving terminals, power ON / OFF relay between MX-10000 in DSP systems is also possible.
A photocoupler is used to transmit the power control signal to prevent degradation of sound quality.

• 
  
• 
• 

Model Rating​

Type	Power amplifier
Rated Output (20 Hz ~ 20 kHz)	8 Ω load : 250W + 250W (0.001% THD) 6 Ω load : 300W + 300W (0.001% THD) 4 Ω Load : 400W + 400W (0.002% THD)
Dynamic Power (1 kHz)	8 Ω load : 350W + 350W 6 Ω load : 450W + 450W 4 Ω load : 600W + 600W 2 Ω load : 900W + 900W 1 Ω load : 1200W + 1200W
Damping factor	1000 (1 kHz, 6 Ω)
Input Sensitivity / Impedance	1.5V/25k Ω
Frequency characteristic	2 Hz ~ 300000 Hz + 0 dB -2dB
Total harmonic distortion factor	0.0005% (20 Hz to 20 kHz, 150W/ch, 6 Ω)
Signal-to-noise ratio	132 dB (IHF-A corrected)
Residual noise	10 μ V (IHF-A correction)
Channel separation	90 dB (20 Hz to 20 kHz)
Pwer	AC100V 50/60Hz
Power consumption	600W
External dimensions	Width 475x Height 220x Depth 543 mm
Weight	43kg

 

[Chrispy]

What's that power consumption spec? Doesn't make sense as max output at least.

 

[EJ3]

What's that power consumption spec? Doesn't make sense as max output at least.

I do not see the spec you are looking for.
Perhaps get one & test it? (Yeah, I know, that doesn't make sense either).
But, unless I were actually wanting to get one, I wouldn't let it bother me.
Even if I was, I may average it being on 2 hours a day a couple times a week.
There are lots of other things that I have to do that keep me from the stereo
(and I do not own a TV, so watching TV is not one of those things)
Doubt that it would have any noticeable effect on my consumption bill.
It's not like a freezer that (even though it runs intermittently & sporadically, it is on all the time).

 

[Chrispy]

I do not see the spec you are looking for.
Perhaps get one & test it? (Yeah, I know, that doesn't make sense either).
But, unless I were actually wanting to get one, I wouldn't let it bother me.
Even if I was, I may average it being on 2 hours a day a couple times a week.
There are lots of other things that I have to do that keep me from the stereo
(and I do not own a TV, so watching TV is not one of those things)
Doubt that it would have any noticeable effect on my consumption bill.
It's not like a freezer that (even though it runs intermittently & sporadically, it is on all the time).

In the post it mentions a power consumption of 600W (but no mention of particular spec for this figure). Yet the output seems to exceed that spec....so need some details that aren't provided. Often it is more related to a regulatory spec than anything particularly useful as "max".

 

[EJ3]

In the post it mentions a power consumption of 600W (but no mention of particular spec for this figure). Yet the output seems to exceed that spec....so need some details that aren't provided. Often it is more related to a regulatory spec than anything particularly useful as "max".

I was kinda' wondering the idle spec (if, say, it was accidently left running).
But, yeah, looking into what you mentioned, I see the same issue that you are seeing.
All the outlets throughout my home are 125V (usually measuring 119-120V) 20 amp rated (as well as the breakers being 20 amp breakers).
Makes me wonder what they were doing in 1968 when the house was built???

 

[Julf]

That text definitely went through a fair bit of hyperbolic transformations.

 

[Scytales]

In the post it mentions a power consumption of 600W (but no mention of particular spec for this figure). Yet the output seems to exceed that spec....so need some details that aren't provided. Often it is more related to a regulatory spec than anything particularly useful as "max".

Yes: that is the reason why relying on the power consumption mentioned in the back of an amplifier or in the spec sheet to compare it to the maximum specified output power of an amplifier is not a good idea.

 

[jsrtheta]

This remains a huge source of confusion for some.

 

[EJ3]

This remains a huge source of confusion for some.

I personally don't care of the power consumption figure's match up to a theory of what the power output should be.
I just want to know does it meet or exceed that numbers that are given about the output under the conditions that they are supposed to happen.
And, if not, is it because something is wrong?
Or because someone is stretching the truth like warm salt water taffy?

 

[SuicideSquid]

I believe 20-20k is just some convenient range decided by someone in the past. It could have been 19-19k or 21-21k or 21-19k or whatever… We don’t have to hold on to it as if it’s some natural law.

Personally I think superb system performance in the 30-15k range is good enough to enjoy HiFi. Any superb performance wider than that is icing on a great cake.

It isn't arbitrary. It represents the full spectrum that most healthy humans can hear, most of the time. And I agree if it was 19-19 or 21-21 it wouldn't make a difference. If a person could actually hear musical notes in the very high frequency range (rather than just hiss) the difference between 20kHz and 21kHz would be approximately a quarter tone. The difference between 19 and 20Hz is a little more than a whole tone, but again, I think when you get down that low it's very difficult to distinguish distinct pitches, it's just a rumble (and most speakers can't produce such a frequency anyway, nor can any musical instrument except perhaps a handful of the world's largest pipe organs produce pitches in that frequency range).

 

[Adis]

What's that power consumption spec? Doesn't make sense as max output at least.

Usually, that's at 1/8 output power.