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24/192 Music Downloads Are Very Silly Indeed (2012)

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Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#21

Post by pizza234 »

acchow wrote: post #7
tomc1985 wrote: post #3

While the extra quality is lost on listeners, from experience I've found that super-HQ source material can change your results (for the better) when fed through distortion/compression/warming effects processors

> Its playback fidelity is slightly inferior to 16/44.1 or 16/48, and it takes up 6 times the space. The article is highly technical. Does anyone have a way to describe this phenomenon intuitively?

The core is here: https://xiph.org/~xiphmont/demo/neil-young.html#toc_1ch

When you play something stored at 44 khz, there are no ultrasonic sounds recorded. At 192 khz instead, there are, and the speakers may push some of the ultrasonic sounds down to the audible spectrum, causing distortion that the human ear can hear.

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#22

Post by sp332 »

squarefoot wrote: post #13

FTA: "192kHz digital music files offer no benefits. They're not quite neutral either; practical fidelity is slightly worse. The ultrasonics are a liability during playback." I would expect the samples to be interpolated before the final DA conversion takes place, so no extra ultrasonics should be involved. And there would be filters for them anyway, we still have to use them for 44.1, 48, 96 etc.

But if you're filtering out ultrasonics, then you've guaranteed that the extra samples will be wasted. There won't be any difference in the reconstructed signal at all.

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#23

Post by sitharus »

fusiongyro wrote: post #14
acchow wrote: post #7

Earlier quoted context omitted.

> Its playback fidelity is slightly inferior to 16/44.1 or 16/48, and it takes up 6 times the space. The article is highly technical. Does anyone have a way to describe this phenomenon intuitively?

Basically, the sampling theorem says you can reconstruct the exact waveform with a certain number of samples. Adding a bunch more samples bulks up the file, but you didn't need them to restore the exact waveform. However, the unnecessary samples are in the file between you and the next sample you do need. At high enough levels of waste this creates an I/O bottleneck that hampers performance. Another way to look at is…

> Increasing the data rate does not continue to make the waveform more and more detailed to human auditory perception in the way that raising the pixel density does for human visual perception.

Early low data rate codecs - such as the one used for GSM mobiles - are obviously inferior, but still functional. I think a better analogy is that an iPhone 7 has a 1 megapixel screen, so there's no difference between a 1 megapixel image and a 5 megapixel image, except one is much larger. Of course visually you can zoom in (or move closer in real life), but audibly you can't.

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#24

Post by tomc1985 »

hamandcheese wrote: post #12
acchow wrote: post #7

Earlier quoted context omitted.

> Its playback fidelity is slightly inferior to 16/44.1 or 16/48, and it takes up 6 times the space. The article is highly technical. Does anyone have a way to describe this phenomenon intuitively?

24/192 can capture audio well beyond what we can hear. These sounds can, though, lead to distortion that is within our hearing range, depending on the equipment used. Therefore, rather than just being useless extra data, it can be actively harmful to the listening experience.

It's not that much different to think of than 480p vs 4K/2160p -- dramatically higher resolution, increasing the width and length of the 'grid' that sound is recorded into -- except that in the case of audio fidelity, quality after a certain point causes problems with playback systems, resulting in audible artifacts and distortion.

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#25

Post by zkSNARK »

hamandcheese wrote: post #12
acchow wrote: post #7

Earlier quoted context omitted.

> Its playback fidelity is slightly inferior to 16/44.1 or 16/48, and it takes up 6 times the space. The article is highly technical. Does anyone have a way to describe this phenomenon intuitively?

24/192 can capture audio well beyond what we can hear. These sounds can, though, lead to distortion that is within our hearing range, depending on the equipment used. Therefore, rather than just being useless extra data, it can be actively harmful to the listening experience.

I doubt that is the case. Most systems which I have used actually sound better at the higher sampling rates. This is not because the sampling rates cause anything to sound better, but because the hardware works better at those rates. In a blind test, you wouldn't be able to decide which one you liked better, only that there is a difference. At least on the machines I have, there are some clearly audible differences.

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#26

Post by anyfoo »

squarefoot wrote: post #13

FTA: "192kHz digital music files offer no benefits. They're not quite neutral either; practical fidelity is slightly worse. The ultrasonics are a liability during playback." I would expect the samples to be interpolated before the final DA conversion takes place, so no extra ultrasonics should be involved. And there would be filters for them anyway, we still have to use them for 44.1, 48, 96 etc.

Wasn't the point that if you have a system capable of outputting a 192kHz analog signal on the DAC, essentially hitting your speakers with 96kHz audio, any non-linearity starting at the DAC and beyond could cause distortion in the actually audible range?

And if you do any downsampling, or any low pass filtering in general, then having 192kHz sampling is even more useless, in addition to only having the "benefit" of adding a frequency band to the spectrum that's completely inaudible anyway.

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#27

Post by anyfoo »

trevyn wrote: post #16
mrob wrote: post #6

Earlier quoted context omitted.

Is that because of the HQ audio, or because the processing software introduces less artifacts at those sample rates/bit depths? I.e. could you get the same results by up-sampling CD quality audio?

I imagine it's because lossy codecs are tuned for human perceptual limitations, and when you process audio, it can "pull" areas of the sound that are otherwise hidden from your perception into perceptual ranges, analogous to how fiddling with the brightness/contrast of a highly compressed JPEG image can accentuate the artifacts.

We are not really talking about lossy codecs here, though, are we?

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#28

Post by willglynn »

fusiongyro wrote: post #14
acchow wrote: post #7

Earlier quoted context omitted.

> Its playback fidelity is slightly inferior to 16/44.1 or 16/48, and it takes up 6 times the space. The article is highly technical. Does anyone have a way to describe this phenomenon intuitively?

Basically, the sampling theorem says you can reconstruct the exact waveform with a certain number of samples. Adding a bunch more samples bulks up the file, but you didn't need them to restore the exact waveform. However, the unnecessary samples are in the file between you and the next sample you do need. At high enough levels of waste this creates an I/O bottleneck that hampers performance. Another way to look at is…

Digital imaging definitely has sampling concerns too:

https://en.wikipedia.org/wiki/Aliasing

Even analog imaging has concerns that are better described in the frequency domain than the spatial domain:

https://en.wikipedia.org/wiki/Airy_disk

https://en.wikipedia.org/wiki/Optical_transfer_function

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#29

Post by TazeTSchnitzel »

mrob wrote: post #6
tomc1985 wrote: post #3

While the extra quality is lost on listeners, from experience I've found that super-HQ source material can change your results (for the better) when fed through distortion/compression/warming effects processors

Is that because of the HQ audio, or because the processing software introduces less artifacts at those sample rates/bit depths? I.e. could you get the same results by up-sampling CD quality audio?

More bits means:

• Less quantisation noise, so your noise floor is a bit lower and therefore, when you're mixing stuff together, you accumulate less noise

• More numerical room to play with, you can scale or shift the volume up and down more without clipping and with less loss of accuracy

With 16-bit CD audio, you can't just convert to 24-bit and suddenly have less noise. You might get more room, though.

As for higher sampling rates (more kHz, if you will), I think Monty mentioned some benefit regarding less sharp aliasing filters (can have a larger transition band from 20–48kHz, say, rather than from 20—22.1kHz), but it's not something I understand the benefit of well.

Re: 24/192 Music Downloads Are Very Silly Indeed (2012)

#30

Post by Veratyr »

Perhaps this is a silly question but the explanations mostly make perfect sense to me but in the case of sample rate, what happens when two waves with very different frequencies overlap?

Say I've got an 18kHz wave and a 9kHz wave and the 9kHz wave is ever so slightly out of phase. Then imagine there are 10 different waves under 20kHz all interfering with each other in different wages.

Is it still possible to reproduce everything accurately?

And on bit-depth and dynamic range: Given that much audio doesn't use the full range available to it, wouldn't higher bit depth increase the fidelity in the range the audio does fill? The article talks about the bit depth and range only in terms of the maximum volume but what about fidelity? What's the minimum difference in volume the human ear can hear?

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