Yes, anyone, even old people can hear 21 kHz (test attached)

[Newman]

I wouldn't call the second signal a square, sounds more like a weird sawtooth to me.

Yes, in fact, the video host actually shows us the spectrum:-

No wonder it is easily distinguishable from a pure 7 kHz sinusoidal tone! This is not the native spectrum of a 7 kHz square wave. This is what happens when we sample high levels of ultrasonic content at a low Nyquist of only 22 kHz, ie sampling rate 44 kHz. The host used a 7 kHz square wave to generate the necessary ultrasonic to create lots of aliasing at audible frequencies, and make his point. His actual point being as I explained in post #16.

Some people are misinterpreting what is really happening.

 

[Sokel]

Yes, in fact, the video host actually shows us the spectrum:-

View attachment 430708

No wonder it is easily distinguishable from a pure 7 kHz sinusoidal tone! This is not the native spectrum of a 7 kHz square wave. This is what happens when we sample high levels of ultrasonic content at a low Nyquist of only 22 kHz, ie sampling rate 44 kHz. The host used a 7 kHz square wave to generate the necessary ultrasonic to create lots of aliasing at audible frequencies, and make his point. His actual point being as I explained in post #16.

Some people are misinterpreting what is really happening.

Thank the gods for Multitone Analyzer,I know how signals sound like after all this tests.
A nice square is very different,I can toggle between all shapes,so...

The intention here probably is to show what happens with bad recording practices in place,which makes sense.

 

[voodooless]

Yes, in fact, the video host actually shows us the spectrum:-

View attachment 430708

No wonder it is easily distinguishable from a pure 7 kHz sinusoidal tone! This is not the native spectrum of a 7 kHz square wave. This is what happens when we sample high levels of ultrasonic content at a low Nyquist of only 22 kHz, ie sampling rate 44 kHz. The host used a 7 kHz square wave to generate the necessary ultrasonic to create lots of aliasing at audible frequencies, and make his point. His actual point being as I explained in post #16.

Some people are misinterpreting what is really happening.

So the irony here is; that the signal is wrong, exactly because the sampling theorem is right. You can’t make this stuff up if you tried

 

[Geert]

With his opening post the OP has broken The Misrepresentation World Record. Throwing in a link to an article of grandpa Paul referencing the flawed research of Oohashi was a nice touch.

 

[Keith_W]

The example given just gives audible artifacts because the experiment has not been done correctly.

This quote should end the thread.

 

[usersky]

No, you cannot hear above 18 kHz, I cannot hear above even less than that. But we can still hear the shape of the waves at 7 kHz or even higher. And in order to reproduce anything other than a sine waveform at 7 kHz, the audio equipment requires 21 kHz. So we can hear if the audio equipment is cutting out above 20 kHz. So for the old people 48 kHz is absolutely necessary, for the young people a lot more than that.

The reality is one: you either can or you cannot hear a certain signal. The way in which you look at the signal (time or frequency perspective) won't change what you hear. Indeed the two signals on yt sound different, try to find the cause in some other places though.

 

[Hayabusa]

This quote should end the thread.

6300 Hz sin and square wave done right I hope

Go ahead and test this yourself, its 2sec of sine wave followed by 2sec of square wave

Edit: my file is also not correct , get the ones from danadam: post

 

[Old_School_Brad]

There is nothing in that video that supports the claims you made that I have emboldened, above.

The video host is only talking about the sample rate used in the ADCs when recording music. Recording music at much below 60 kHz has the potential to audibly misrepresent ultrasonic content created by the musical instruments, reflecting back down into the audible band as aliasing artefacts.

Once we have captured the music (say at 24/96 as per the industry norms), then these aliasing artefacts are prevented from reflecting into the audible band, then we can resample that recording into any rate 44 kHz and above (for distribution, transmission and playback) and it will sound exactly as it should.

Nobody is hearing any harmonics above 20 kHz. You misunderstand what is going on.

cheers

I don’t think this study has been shared here before, but it’s definitely interesting and confirms once again that our hearing isn’t good enough to require hi-res audio for satisfaction.

Spoiler: High-frequency sound components of high-resolution audio are not detected in auditory sensory memory

High-frequency sound components of high-resolution audio are not detected in auditory sensory memory - Scientific Reports

High-resolution digital audio is believed to produce a better listening experience than the standard quality audio, such as compact disks (CDs) and digital versatile disks (DVDs). One common belief is that high-resolution digital audio is superior due to the higher frequency (> 22 kHz) of its...

www.nature.com

"In conclusion, even if high-resolution audio is superior to the standard format, the difference is apparently not detectable at the cortical level."

 

[Thomas_A]

My take if it is "real" hearing that high frequencies it is either unbelievably high SPL or IMD of the equipment or the ear.

 

[solderdude]

Reproduction gear (especially transducers) can have a different fidelity and usually act problematic at these frequencies especially at different SPL.
Even devices like DACs may behave differently or class-D amplifiers can do so.
Pointless endeavor to prove we can hear above frequencies the ear is not intended to detect.

 

[antcollinet]

No, you cannot hear above 18 kHz, I cannot hear above even less than that. But we can still hear the shape of the waves at 7 kHz or even higher. And in order to reproduce anything other than a sine waveform at 7 kHz, the audio equipment requires 21 kHz. So we can hear if the audio equipment is cutting out above 20 kHz. So for the old people 48 kHz is absolutely necessary, for the young people a lot more than that.

Your ears actually detect sound in the frequency domain. The cochlear decomposes the signal into the component frequencies using a structure that is effectively a bio-mechanical Fourier transform machine. The highest frequency detector is about 15kHz, the side bands of which go up to about 20kHz (for people with perfect hearing). This is why sensitivity even for perfect hearing drops dramatically as you go above 15kHz.

So, no - if the shape of a waveform is caused by frequencies above 20kHz, you cannot hear that shape. The inner ear acts as a low pass filter so that only the frequencies below 20kHz (or much lower for most people) result in signals being sent to the brain. If that signal in the video were constructed properly as described - without artefacts resulting in additional audible frequencies (such as aliasing/imaging, or IMD in the speaker/headphone), then that signal is indistinguishable, to the human auditory system, from a 7kHz sine.

 

[Newman]

...this significant information:
Here, go watch for a few seconds:
What is the Optimal Sampling Rate for Audio? (It's All About the Aliasing)
(The link starts at 15:48)
That is worth some comments.

The only comment "that it is worth" is that it is false. Check @rationaltime's discrete thread to discuss it, where it is quickly debunked in posts #4, #5.

 

[Newman]

Yeah the dying CD industry overlords will summon all their marketing firetruck teams to defend their silly 16/44 myths carefully planted over decades

Thanks for showing your true colours. It is a bit ironic, don't you think, that in your rush to spraypaint the CD format as based on silly myths, you forgot to make sure that you aren't planting a myth of your very own?

Are you willing to revisit the silly myths (your term) that litter your post #1? I mean, now that you have read the replies and you understand what is actually happening.

I sure hope that you aren't busily researching a defence based on more references to Paul McGowan. People who follow McGowan usually need to unlearn an awful lot of audio myths before they can start to re-learn the basic realities of audio perception and sound quality of gear.

 

[Ralph_Cramden]

We're all here to learn. Let's hope that @Newman's very clear explanations have taught @Andro something that he can take back to his other less rigorous forums.

 

[kemmler3D]

We hear the shape of a wave in its entirety, not as a spectrum of harmonics

What do you think makes up the wave other than harmonics?

 

[Barrelhouse Solly]

In my case, a number of audiologists would dispute that. My audiogram is very clear on the subject. With hearing aids I top out at about 8KHz. Without my audiogram rolls off precipitously above 2KHz.

 

[kemmler3D]

Can people really hear harmonics or at least distinquish audio difference of say a violin or piano that are above 20k hz? Besides being of too high frequency, wouldn't their amplitude be too low?

No and yes. Even if you could hear 40khz just as well as you hear (say) 15khz, (which even oohashi doesn't claim) usually the amplitude of ultrasonic content is really low and would probably be masked.

 

[sam_adams]

What the extracted audio track looks like in Audacity (m4a):

Here's the spectrogram from Audacity:

And the spectrogram from the .m4a track exported from Audacity as a 96KHz, 32-bit float .wav file and imported into REW:

 

[danadam]

Here is the spectrogram of the audio in the file. Obviously it isn't a clip of just alternating 7 kHz sine and 7 kHz square waves.

Maybe he changed the file in the meantime, but it doesn't look so bad here (gain 0, range 120):

6300 Hz sin and square wave done right I hope

Go ahead and test this yourself, its 2sec of sine wave followed by 2sec of square wave

Your "square" wave seems to have 2nd harmonic (and quite a lot of DC):

you will easily hear alternative patterns of different tone.

What I can hear are the discontinuities at the moment of switching. When the test file is prepared properly, like the one in attachment, I can hear only a single tone:

I also included 4 kHz so you can hear what it sounds like when you can hear the higher harmonic (well, at least those who are still able to hear 12 kHz )

 

[Titurel]

What do you think makes up the wave other than harmonics?

Honest question: Do really mean this or do you mean any wave can be reconstructed from sine waves? The accuracy of such would seem to be limited by rise time, which cannot be zero. Your statement (which I'm honestly trying to understand) also seems to presume that any waveform exists only as the sum of the harmonics, from which they might be re-synthesized, rather than being sui generis.

Be kind in your answer, my mathematical skill are more than rusty.