Audiophiles Rejoice: The Nyquist–Shannon sampling theorem actually proves high-res audio is real and works

[PaulD]

As a side note, took 10 posts to invoke the Monty! Have seen Monty used as early as 3 posts, and as late as 20 pages in.

Haha, I called in Monty on my first post in the thread and I think I have invoked The Monty 3 times at least across ASR in the last 12 months - he's excellent at dispelling audiophile BS such as "sampling misses information between the samples" and "digital audio has timing problems" etc etc.

On the issue of audio above 20KHz, at what distance is the listening? Air absorption at 40KHz is 1.3dB/m, at 80KHz it's 2.6dB/m. Given that such high harmonics are much lower in amplitude and duration anyway. Being 3-6m away puts the harmonics another circa 6-12dB down EVEN IF YOUR BASILAR MEMBRANE COULD RESPOND TO THEM - HF absorption calculator here http://www.sengpielaudio.com/calculator-air.htm

 

[maxxevv]

Playing devil's advocate:
https://www.cco.caltech.edu/~boyk/spectra/spectra.htm



I want to hear the authentic reproduction of cymbals!!

"Feeling" sound below hearing spectrum yes. Ultrasonics ? There's no mention of how is that affirmed by the listener.

 

[raistlin65]

Another study has been referenced here too, showing a small but not insignificant % of people detected signals in the range of 20k and slightly higher.

Which begs the question, what percentage of the recordings would be mixed by people who can hear over 20K?

"Oh, wow, I can hear over 20K content in this recording."

"Sorry. Hate to tell you, but a mosquito flew by the mic. And our recording engineer can't hear over 20K, so it ended up in the final master."

 

[whazzup]

"Feeling" sound below hearing spectrum yes. Ultrasonics ? There's no mention of how is that affirmed by the listener.

Fine. I want to FEEL the authentic reproduction of cymbals!! From my speakers!

 

[whazzup]

Have some keys on a keyring in your pocket? Bring them out and jangle them. The majority of the energy is above 20 khz and pretty loud. It will sound like a soft tinkle to you all the same.

That could explain why my rabbits hate it when I drop my keys on the tiles! HF explosion!

 

[MC_RME]

I want to hear the authentic reproduction of cymbals!!

You don't. They are damn loud and peaking in your ear. Just go to the next music shop, sit down at the drum set and hit them. Cymbals on recordings are heavily equallized to sound 'nice'.

 

[Leporello]

The key to his argument is in the first paragraph:

So, I was reading on some forums online about how this theorem proves that CD quality sound fully reproduces the original analog audio signal “perfectly” and high-res is “fake news”.

It is common knowledge - and always has been - that proper functioning of digital audio necessitates filtering out the frequencies at or greater than half of the sampling frequency.

But this guy then builds a straw man argument by understanding the words "fully" and "perfectly" literally. Yawn.

 

[whazzup]

You don't. They are damn loud and peaking in your ear. Just go to the next music shop, sit down at the drum set and hit them. Cymbals on recordings are heavily equallized to sound 'nice'.

Sorry! What did you say!! You need to speak up!

 

[Frank Dernie]

https://link.medium.com/ktiNtRo1m8

I like ASR, would be interesting to hear what you think about this article.

There is an old saying "it is better to keep your mouth shut and have everybody think you are a fool than say something and prove it"
This goes for writing too, all too common on the internet.

 

[pozz]

"Problem is, many trained musicians & studio engineers can experience the effects of vibrations above and below what humans can hear, when the signal is played back."

This is that poorly done study by Oohashi et al coming in to mislead and bite the world in the ass.

 

[mansr]

I'm disappointed. 30 posts and nobody has managed to muster the correct response: uh-huh.

 

[mansr]

My understanding (from things I’ve read here) is, below 20hz, yes absolutely. Above 20khz? I can’t imagine that would feel like vibration, maybe pressure. I’m not a headphone guy, so maybe??

If you want to know what it feels like, stick a finger in an ultrasonic cleaner.

 

[pozz]

Which begs the question, what percentage of the recordings would be mixed by people who can hear over 20K?

"Oh, wow, I can hear over 20K content in this recording."

"Sorry. Hate to tell you, but a mosquito flew by the mic. And our recording engineer can't hear over 20K, so it ended up in the final master."

Babies and very young children generally can (but hear less bass), due to the size of the ear. As they older and bigger the range shifts downwards to the regular 16kHz, give or take.

 

[Vini darko]

From the article:


So can people really be trained to 'feel' the vibration above 20k? Not a musician / audio engineer, so I'm curious about the validity of this statement. Does that also mean they'll respond to me when I use a dog whistle?

Only if you have treats in your pocket

 

[Sgt. Ear Ache]

I've been playing guitar for 30 years. Last time I checked, my hearing pretty much tops out at 14.5khz. I'd love to see the writer of this article take a hearing test...

 

[Jimbob54]

I've been playing guitar for 30 years. Last time I checked, my hearing pretty much tops out at 14.5khz. I'd love to see the writer of this article take a hearing test...

Ah , but do you hear the vibrations above that with your trained musician ears? If you dont, you cant be a proper expert like that guy.

 

[pkane]

Ah , but do you hear the vibrations above that with your trained musician ears? If you dont, you cant be a proper expert like that guy.

Ultrasonically vibrating golden ears

 

[Sgt. Ear Ache]

Ah , but do you hear the vibrations above that with your trained musician ears? If you dont, you cant be a proper expert like that guy.

Oh, I'd never in a million years claim to be a "proper" expert! lol

 

[John Dyson]

All too often, the problems with comparing sample rates is the use of not-linear phase filters, and the various group delay characteristics of the filters. A not-linear phase brickwall can have effects well into the audio spectrum, but they are not level differences, they are TIMING and propagation differences. Linear phase (constant delay) are absolutely necessary for controlling the experiment, unless all group delay errors have been compensated. (If this very general, and almost non-technical statement isn't clearly understood with nuance, then don't bother trying to do an experiment. This can be subtle stuff, and strange/erroneous results are very easy to achieve.)

The measurements must be controlled, and done with very careful engineering (I mean, DSP/human factors researcher level and defended), because there are so many variables (including human hearing changing vs time, and a 5-15 second accurate memory for many people.) Gotta understand some statistics also -- making sure that when there ARE random errors, they are at least partially filtered. Biased results (e.g. ham-handed choice of rate conversion software), doesn't help increase the knowlege base for anyone.

I don't mean to sound critical, but I have seen a lot of arguments that even I (just a fairly/reasonably knowlegable DSP person, writing really innovative software, but not the biggest expert in the world) can legitimately be critical and argue away many/most claims about high res sample rates. That doesn't mean that high res sample rates are never useful -- because they are, but not really in linear applications like presentation/playout. As long as you have 48k (I don't like 44.1k for emotional bias reasons), you are able to provide whatever human ears can receive. (Well, I don't like hiss either, and prefer wiggle room, so at least 16bits is best.) If you are doing ANYTHING nonlinear, then it is a good thing to have wiggle room (almost literally) in the sample rate, and usually 96k is a good choice, but I can almost always get by with 66.15k or 72k to save CPU and filter taps.

John

 

[Jimbob54]

Got to love a site that regularly references the holy trinity of audiophoolery

PS Audio, Bob Stuart/MQA AND DARKO!!!!!

I think he knew how this was going to play out here, Just looking for quotes to copy and paste elsewhere to rebut?

Just answer me this- lets just for a minute assume there is some merit in very high sample rates/ DSD etc . Why quote PS audio, and reference their DAC that converts PCM to DSD on your page when this is the same company that insists on spraying distortion over everything on the output side? https://www.audiosciencereview.com/...f-ps-audio-perfectwave-directstream-dac.9100/

A little contradictory, no?

Oh, and I truly am a know -nothing. But even I recognise the smell of prize winning BS.