xiphmont’s ‘There is no point to distributing music in 24 bit/192 kHz’, Article: “24/192 Music Downloads are Very Silly Indeed” Options

[NullC]

Of interest, but certainly not news to anyone here is Monty's educational piece regarding the lack of value of 24/192 as a distribution format:

http://people.xiph.org/~xiphmont/demo/neil-young.html

Some of the commentary on the internet has been not especially well informed, for example there are some crazy claims at https://news.ycombinator.com/item?id=3668310. If you're in a "someone is wrong on the internet!" correcting mood, you might want to go leave some comments in furtherance of the collective intelligence of mankind.

Cheers

[NullC]

It's also on slashdot now: http://news.slashdot.org/story/12/03/06/00...ds-is-pointless

[Canar]

[mudlord]

[DigitalMan]

Very, very nicely done. Long live TOS #8.

[Carledwards]

Excellent. Glad to see this and I hope it gets widespread attention.

[Batman321]

Great article!


Meanwhile in a parallel universe where science is for losers who aren't rich enough to buy insanely expensive gear:

SH Forums

[Porcus]

At the risk of spinning off a digression: what is the maximum effective number of bits available in a DAC these days -- and does that number depend on the sampling frequency?

[skamp]

^^^ http://nwavguy.blogspot.com/2012/03/odac-update.html

ENOB stands for Effective Number of Bits and is another measure of a DAC’s performance. No 24 (or 32) bit audio DAC can achieve true 24 bit performance, In fact, 20 ENOB is generally considered the “Holy Grail” of real world DAC performance. The ODAC is just under 19 ENOB and the Benchmark [DAC1], even referenced to its full 7+ volt maximum output, is 19.3 ENOB. The FiiO E10, even in 24 bit mode, is only 16.2 ENOB.

Note: the guy is touting his own design for a DAC/headphone amp combo (referenced above as ODAC), but he has a good track record of providing what looks like precise measurements, and making sense…

This post has been edited by skamp: Mar 6 2012, 10:31

[AndyH-ha]

The answer depends on conditions, like the chem lab experiments. At standard temperature and pressure ... .
20 bits is pushing the limit for practical purposes, thermal noise is too high for anything better. For some endeavors, such as some aspects of radio astronomy, cutting edge particle physics, and military systems, cryogenic cooling is practical and common place. Liquid nitrogen, or even more extreme materials, with the low temperatures they provide, considerably reduce the intrinsic device noise levels.

Sampling frequency and bit depth are independent of each other.

[hlloyge]

Finally. Thank you.

[razer]

Such a great read.

[Porcus]

Sampling frequency and bit depth are independent of each other.

So ... at least it is not the case that a DAC fed a 192/24 signal as oppsed to a 48/20 or 44.1/16, will have to operate at higher load --> more thermal noise --> lower e.n.o.b.?
(Shouldn't be, it is not that demanding?)

[DonP]

Sampling frequency and bit depth are independent of each other.

Delta sigma?

[Arnold B. Kruege...]

At the risk of spinning off a digression: what is the maximum effective number of bits available in a DAC these days -- and does that number depend on the sampling frequency?

Effective number - you mean in terms of resolution that is actually delivered to the analog domain?

Check the TI and ESS web sites. They seem to be flogging the SOTA in this regard the hardest.

I think that noise down 133 dB down is the SOTA - what about 21 bits? If you want to be hard to please you would also demand that spurious responses (IM+THD) would also be part of the equation, in which case things seem to be about 3-6 dB worse.

I basically agree with the 20 bit number that others have put forth.

There is a strategy for improving the dynamic range of a DAC that can be expanded almost endlessly, at a increasingly high cost. Run multiple DACs that each generate statistically independent noise in parallel. Dynamic range improves by 3 dB for every doubling of DACs. I believe that ESS goes to 4x or even 8x for specing their products.

The progression is:

2 DACs in parallel, get a 3 dB improvement
4 DACs in parallel, get a 6 dB improvement
8 DACs in parallel, get a 9 dB improvement
16 DACs in parallel, get a 12 dB improvement
...

Thing is, this does nothing for spurious responses because they are always coherent, like the signal. The ratio between spurious responses and signal remains the same as you add DACs.

In the past people have run DACs in antiphase which can help even-order distortion. But you only get one iteration of that approach.

As DAC functionality gets cheaper and cheaper, the numbers race may cause these approaches to be more common. But, a good single DAC is overkill enough!

This post has been edited by Arnold B. Krueger: Mar 6 2012, 14:42

[Arnold B. Kruege...]

Sampling frequency and bit depth are independent of each other.

Delta sigma?

After measuring about a hundred audio interfaces, the overwhelming majority being Sigma-Delta, it seems to be a general rule that the best effective performance is found at lower sample rates (e.g. 44 KHz), all other things being equal.

[dumdidum]

Monty: "The more that pseudoscience goes unchecked in the world at large, the harder it is for truth to overcome truthiness... even if this is a small and relatively insignificant example."

Meanwhile in a parallel universe where science is for losers who aren't rich enough to buy insanely expensive gear:

SH Forums

That SH forum thread you linked reminds me of creationism. I wouldn't be too optimistic about convincing such "audiophiles" by appealing to science and logic.

This post has been edited by dumdidum: Mar 6 2012, 14:53

[Martel]

Sampling frequency and bit depth are independent of each other.

Theoretically maybe. But this is definitely false for integrating ADCs (commonly used in digital voltmeters) which have have a reciprocal relationship between accuracy (bit depth) and sampling rate.

This post has been edited by Martel: Mar 6 2012, 15:18

[Wombat]

Some of the commentary on the internet has been not especially well informed, for example there are some crazy claims at https://news.ycombinator.com/item?id=3668310. If you're in a "someone is wrong on the internet!" correcting mood, you might want to go leave some comments in furtherance of the collective intelligence of mankind.

One more page to link to if asked for some explanation, many thanks for that. What saddens me is the resulting discussion on this news channel.
There the typical "I am enigineer" come in and simply claim that "Nyquist was wrong because i can hear all these harmonics!"

[saratoga]

Sampling frequency and bit depth are independent of each other.

So ... at least it is not the case that a DAC fed a 192/24 signal as oppsed to a 48/20 or 44.1/16, will have to operate at higher load --> more thermal noise --> lower e.n.o.b.?
(Shouldn't be, it is not that demanding?)

Usually they operate at about the same internal clock speed regardless of sampling rate, just with different oversampling ratios. Wouldn't make sense to run a DAC made for high speed operation at a lower speed, since more oversampling means less risk of aliasing and generally less quantization noise.

Also, in this context, thermal noise doesn't necessarily refer to the temperature of the A/D alone, but also to the temperature of everything its hooked up to. The terminating resistance in whatever the A/D is reading still contributes the same thermal noise no matter how cool you make the A/D for instance. This is why refrigeration is not a great option like it is in optical detectors.

[Satellite_6]

"It's hard to fake ambisonics or holographic audio, sort of like how 3D video always seems to degenerate into a gaudy gimmick that reliably makes 5% of the population motion sick."

"If it wasn't the most boring party trick ever, it was pretty close."

haha!

Very amusing and very informative. I just want 16/44.1 lossless downloads, so to whoever starts offering that on a wide scale, shut up and take my money.

[jensend]

By the by, I recently added a little writeup about TOS 8 on the wiki. Thought I'd mention it after seeing Monty referencing TOS 8.

This post has been edited by Frank Bicking: Mar 6 2012, 23:17

Reason for edit: Fixed link.

[soulsearchingsun]

From the article:

Audibility of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio Playback [...]
Not one listener throughout the entire test was able to identify which was 16/44.1 and which was high rate, and the 16-bit signal wasn't even dithered!

Not to be nitpicky, but IMHO you only dither if you resample digitally?

[klonuo]

By the by, I recently added a little writeup about TOS 8 on the wiki. Thought I'd mention it after seeing Monty referencing TOS 8.

While there, someone could also fix links in pointed ABX article - all but one external links are 404

This post has been edited by klonuo: Mar 7 2012, 00:05

[wakibaki]

I'm happy to see a truly coherent argument against the necessity for higher bit depths and sample rates.

Waste of storage space is a small margin of disadvantage however. The advocates of 24/96 and higher were happy to pay the cost of increased storage space to achieve a perceived advantage, and storage space (or transmission bandwidth) is an increasingly cheap commodity.

This leaves us with degradation of fidelity as a result of processing unnecessary ultrasonics. Unfortunately the very same tests (Meyer and Moran) we used to make our case previously now mitigate against us. If a 16/44k1 bottleneck is inaudible in a system avowedly processing ultrasonics, then the ultrasonics cannot reasonably be said to have (audibly) degraded the sound.

w

This post has been edited by wakibaki: Mar 7 2012, 01:01