There is no point to distributing music in 24-bit/192kHz format. • Hacker News Board

Re: There is no point to distributing music in 24-bit/192kHz format.

#21

Post by [deleted] » Mon, Mar 05, 2012, 10:02 PM UTC

cmer wrote: post #12

Joeboy wrote: post #10

Earlier quoted context omitted.

> Digitally recording a triangle is the best example of why 48kHz is very limiting The article's about distribution, not recording. I don't think anybody disputes the usefulness of higher sampling rates when recording. > In theory, it's true that the human hear can't hear above ~18kHz, but it can hear the influence of the very high pitch harmonics on a lower frequency. ...and 48kHz audio contains those lower frequenc…

Stripping frequencies above 20kHz negates the effect on the lower frequencies since those lower frequencies are not "modified" by the higher ones. The human hear can actually hear the very high harmonics when they're combined with a lower fundamental frequency. For example, the human hear will hear a 30kHz frequency if it's fundamental is 10kHz. If it's played at 44.1kHz, the 30kHz frequency is gone and all you'll he…

[deleted]

Re: There is no point to distributing music in 24-bit/192kHz format.

#22

Post by cmer » Mon, Mar 05, 2012, 10:02 PM UTC

amouat wrote: post #16

cmer wrote: post #4

There's a lot of scientific-sounded content in this, but unfortunately most of it couldn't be further from the truth. I'm an ex-audio engineer and studied digital and analog audio engineering; this has been debated to death over the last 15 years. Digitally recording a triangle is the best example of why 48kHz is very limiting. The distinct sound of the triangle constitutes of a high fundamental frequency, ballpark 5…

I'm no sound engineer, but as far as I can tell, the main point of that paper is that some instruments produce harmonics at frequencies greater than 20kHz, not that these frequencies matter to humans. However, section X references other papers that apparently make this claim. Just because it is difficult to record a triangle does not necessarily mean it is impossible to accurately recreate the sound (to human ears) u…

The only "good sounding" triangles you'll hear are those buried in a mix. Alone, it always sounds weird and "muted".

EDIT: Listen to the triangle at the beginning of Rush's YYZ. It's an old recording, but it sounds significantly worse than the analog version. It's been digitally mastered some time ago so if it was mastered today, it would probably sound better, but still not great. I heard a rumor that Rush is remastering all their albums "for iTunes" at the moment, so hopefully we'll be able to compare soon!

Re: There is no point to distributing music in 24-bit/192kHz format.

#23

Post by masklinn » Mon, Mar 05, 2012, 10:03 PM UTC

coopersloan wrote: post #3

Huh, I think people truly advocating 192 as a distribution format will be few and far in between, a really good and cheaper sampling system can be put together at 96. Still, a lot of things in this article perplex me. Human hearing is limited to 20k because frequencies higher than that are perceived as painful? Dont agree with that one. 24 bit doesn't offer any advantages to sound quality? Sheesh. And the crux of the…

> Human hearing is limited to 20k because frequencies higher than that are perceived as painful? Dont agree with that one.

You misread the article. It's because there is so little response that being able to hear it would blow your eardrums (and even then, it might still be beyond your ability to hear it). There's no value in that.

> 24 bit doesn't offer any advantages to sound quality? Sheesh.

Not quite what TFA says. According to the article, 16 bits effectively covers the dynamic range of human hearing, so more than that is pointless for music consumed by human beings (hence all the stuff about 24bit being a good idea for mastering & production). If you're storing integers in the 0~16384 range, going from 16 bit integers to 32 bit ones is not going to give you "better ints", it's just going to waste 2 bytes per int. Same thing here.

Re: There is no point to distributing music in 24-bit/192kHz format.

#24

Post by leif » Mon, Mar 05, 2012, 10:05 PM UTC

leephillips wrote: post #17

cmer wrote: post #4

There's a lot of scientific-sounded content in this, but unfortunately most of it couldn't be further from the truth. I'm an ex-audio engineer and studied digital and analog audio engineering; this has been debated to death over the last 15 years. Digitally recording a triangle is the best example of why 48kHz is very limiting. The distinct sound of the triangle constitutes of a high fundamental frequency, ballpark 5…

The linked article was accurate. You are confused. "I'm an ex-audio engineer" Hard to believe. "The distinct sound of the triangle constitutes of a high fundamental frequency, ballpark 10kHz" That's a pretty high note - higher than the top key on the piano. But an "audio engineer" would know that. "many very high-pitch harmonics" Since the next harmonic after the fundamental would be at 20khz, which only young people…

You clearly have little to no musical background, and think that your basic math skills are a substitute. The overtones present in a cymbal or triangle are not straight multiples of the fundamental, they are chaotic, and are very important in determining the timbre. Anyone (and I mean that) can easily tell the difference between a cymbal with and without a low-pass filter with the threshold around 22kHz, because these "inaudible" frequencies are lost.

Re: There is no point to distributing music in 24-bit/192kHz format.

#25

Post by mindslight » Mon, Mar 05, 2012, 10:05 PM UTC

sliverstorm wrote: post #9

So, presuming we take this example: http://people.xiph.org/~xiphmont/demo/jaggy2.png The key to reproducing the original signal from the digital signal is a low-pass filter that rejects everything above the sampling rate, correct? That is to say, what I am getting at is while the original signal can be reproduced, it requires properly tuned, and probably reasonably high performance, hardware to remove the higher freq…

Your question is somewhat amusing. A standard CD player uses 1-bit DAC (it's either on or off) at a yet-higher frequency to achieve better linearity. Filtering is quite easy in the analog world.

Re: There is no point to distributing music in 24-bit/192kHz format.

#26

Post by Joeboy » Mon, Mar 05, 2012, 10:08 PM UTC

wickedchicken wrote: post #14

For an article containing a lot of "well, if you knew signal processing..." there are two fairly major oversights: 1) Any well-designed system is going to have headroom. Period. Just because 48kHz can capture the frequencies the human hear theoretically, it's always good to have a little wiggle room. This comes into play even more with interactive situations: humans are particularly sensitive to jitter. Having an "ov…

> I don't know if the human ear can discern the difference between 0.03ms and 0.005ms but it's something I don't see mentioned often

That's the time it takes sound to travel 8mm. Do you think you could tell if an instrument was positioned differently by 8mm?

Re: There is no point to distributing music in 24-bit/192kHz format.

#27

Post by brigade » Mon, Mar 05, 2012, 10:09 PM UTC

coopersloan wrote: post #11

brazzy wrote: post #5

Earlier quoted context omitted.

"Don't agree with that one" and "Sheesh" are pretty weak counters to detailed, objective arguments based on extensive research and decades of test data.

Principle frequencies well above 20k as well as their sympathetic harmonics are pretty easily audible by me, try it. 24 bit is also extremely easy to hear. Arguably more important during the recording phase when headroom is valuable. Its just as easy to qualify everything with "placebo effect", as it is to be dismissive

As he mentions, with 16-bit it's easy to significantly reduce the dynamic range or clip; you only get the full 120dB range of 16-bit with careful handling and calibration. You don't have to worry about all this with 24-bit - you'd almost have to deliberately screw up the signal to reduce the dynamic range below that of a human's.

Ideally audio engineers would take the effort to do good 16-bit conversion for distribution, but I realize that's too much to expect of them.

Re: There is no point to distributing music in 24-bit/192kHz format.

#28

Post by ars » Mon, Mar 05, 2012, 10:09 PM UTC

wickedchicken wrote: post #14

For an article containing a lot of "well, if you knew signal processing..." there are two fairly major oversights: 1) Any well-designed system is going to have headroom. Period. Just because 48kHz can capture the frequencies the human hear theoretically, it's always good to have a little wiggle room. This comes into play even more with interactive situations: humans are particularly sensitive to jitter. Having an "ov…

0.03ms is 33kHz - you can't, no matter how much you want to, make a granular timing that is faster than at least one cycle of the frequency you are using. 0.005ms is 200kHz BTW.

Re: There is no point to distributing music in 24-bit/192kHz format.

#29

Post by jaylevitt » Mon, Mar 05, 2012, 10:10 PM UTC

wickedchicken wrote: post #14

For an article containing a lot of "well, if you knew signal processing..." there are two fairly major oversights: 1) Any well-designed system is going to have headroom. Period. Just because 48kHz can capture the frequencies the human hear theoretically, it's always good to have a little wiggle room. This comes into play even more with interactive situations: humans are particularly sensitive to jitter. Having an "ov…

I'm pretty sure that #2 isn't true; signal processing folks will be able to phrase this better than I can, but I think that if you have enough information to capture the waveform at a given frequency, you also have enough information to precisely place it in time - phasing errors are more likely due to quantization error, which is about bit depth, not sample rate. No?

Re: There is no point to distributing music in 24-bit/192kHz format.

#30

Post by cmer » Mon, Mar 05, 2012, 10:10 PM UTC

tompagenet2 wrote: post #6

cmer wrote: post #4

There's a lot of scientific-sounded content in this, but unfortunately most of it couldn't be further from the truth. I'm an ex-audio engineer and studied digital and analog audio engineering; this has been debated to death over the last 15 years. Digitally recording a triangle is the best example of why 48kHz is very limiting. The distinct sound of the triangle constitutes of a high fundamental frequency, ballpark 5…

Hey cmer, thanks for posting I don't think I understand quite what you're saying and wondered if you could explain more. You and the article both say that humans can't hear above about 20kHz. If there are higher frequencies that create a harmonic at a lower frequency (e.g. a 33kHz harmonic that produces a sound at 16.5kHz) then surely that lower harmonic (16.5kHz in this case) will be recorded by the original recordi…

Let's make things super simple. Let's say you record 4 sine waves at a 192kHz sampling rate: 15kHz, 30kHz, 45kHz and 60kHz. All 4 frequencies will be captured and the 15kHz frequency will sound different to your hear because its harmonics.

If you take this recording and master it for a CD (44.1kHz), you'll effectively get up to ~20kHz (since they're a low pass filter starting at around 16-18kHz). This means that only our first frequency will be captured: 15kHz. It will be exactly the same as if you only recorded 15kHz alone. The harmonics don't modify the fundamental frequency, they just trick the human hear. But when they're gone, they have no effect whatsoever.

Hope this helps!

EDIT: the frequency numbers I used are actually somewhat of a bad example. Harmonics are never exactly double, triple the fundamental. Those would be mostly inaudible. But you get the idea.