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24/192 music downloads are silly

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Re: 24/192 music downloads are silly

#131

Post by Wicher »

masklinn wrote: post #30
errantspark wrote: post #18

I once spent ~2 hours explaining all of this (well maybe not all of it) to a friend of mine who was studying sound design at the time. He didn't believe me. I even transcoded some 24/192 FLAC Pink Floyd I had lying around and made him do a double blind test to show him that he'd prefer the slightly louder song every time, even if the louder song was 192kbps vs the FLAC. He did. He still doesn't believe me. He still t…

> Some people buy $500 wooden knobs to make their volume pots sound better. (or was that a hoax? i can't tell anymore) Some people buy small pyramids to elevate their cables off the floor, some people buy mats to put onto your CDs before putting the CD in a player ( http://dagogo.com/millenniums-m-cd-mat-carbon-cd-damper-revi... ), some people buy $1000+/meter digital interconnect cables ( http://www.theabsolutesound…

> some people buy mats to put onto your CDs before putting the CD in a player

An 80-minute, 700 MB CD-R fits 80 * 60 * 44100 * 2 * 2 / 2^20 ~= 807 MB of audio.

Why is that?

The 100MB difference is not just due to the audio TOC being of smaller size than the ISO9660 or UDF file system metadata. It's also because of differences in error correction. I don't have the spec on hand but I recall from when I was investigating this that CD-ROMs use more bits for error correction than audio CDs. That's why you can fit more audio data than "filesystem data" on a CD-R. Reading (ripping, digitally) an audio CD will likely result in different digital audio files every time, since the error correction is not that good, but good enough, for audio.

I read into this when I was wondering why my CD-DA extracted .wavs came out with a different checksum every time. Vibration is one of the factors that would make the same audio CD, read with the same CD player, produce different digital signals some of the time or even every time.

CD-ROMs however, which store digital data, need better correction - you definately don't want a bitflip in your .exe, while a minor amplitude diff — an uncorrected bitflip in the upper bits of a 16-bit PCM signal — is no biggie.

So… I'm not saying that the people using CD mats are informed (or have tested whether the mat makes a difference, or would even know how to go on about testing this, scientifically), but there's more to it than what I originally thought — which was "it's digital so it's never degraded". I wouldn't have known without checking the md5sum of my .wav, though.

Re: 24/192 music downloads are silly

#132

Post by lmm »

You can't simultaneously say that you're dithering to represent low amplitudes while also saying you're keeping enough samples to capture all audible frequencies. Dithering doesn't create resolution out of nowhere, it sacrifices temporal resolution for amplitude resolution. It's also bad for compression (hence why modern video encodes are done at 10-bit even for output to 8-bit devices), and worse if you want to use a source as the basis for further work (i.e. a remix). If you want to store your signal in a simple, convenient way, and not have to carefully tweak the levels for each individual recording, 16 bits isn't quite enough. And as the article admits, extra resolution certainly can't hurt; worst case is the extra bits are thrown away.

Also 44.1KHz is a pain to do in realtime (there's not enough headroom to really filter out the higher frequencies without damaging the 20KHz response), meaning you need a separate mastering step which is inconvenient and frankly unnecessary. 48KHz is a much more sensible standard to work with.

192KHz may be dumb, but 48KHz/24-bit is perfectly sensible. It gives you fewer ways to make mistakes than CD-quality (44.1KHz/16-bit), and at some point the extra space is worth that, particularly since it may well compress better than a dithered 16-bit signal.

Re: 24/192 music downloads are silly

#134

Post by geographomics »

nkurz wrote: post #55

No one can see X-rays (or infrared, or ultraviolet, or microwaves). It doesn't matter how much a person believes he can. Retinas simply don't have the sensory hardware. The author seems to have stumbled into a poor example, as a recent study shows that humans can indeed see infrared light using an unexpected process. Should we read anything into the audio case from this? Probably not, but it's a sign that even those…

More rarely, there's also tetrachromacy, which is thought to improve colour differentiation within the visible spectrum, and aphakia, which causes an increased sensitivity to the near ultraviolet.

Re: 24/192 music downloads are silly

#135

Post by aidenn0 »

nkurz wrote: post #115
sillysaurus3 wrote: post #64

Earlier quoted context omitted.

Openmindedness isn't the same thing as being open to accepting a mistaken belief. If no one can tell the difference between 24-bit and 16-bit, then 24-bit simply doesn't matter. The only way to know is with a controlled experiment that checks whether the people can detect no better than chance whether music is 24-bit.

Openmindedness isn't the same thing as being open to accepting a mistaken belief. Perhaps not, but I think it's very close. I'm not advocating for noncritical acceptance of anything, but making the point that any jump from "X is a physical law" to "Y is impossible" depends critically on the assumption that the only way to achieve Y is through X, and that there is no possibility of a back door that entirely sidesteps…

> I'd probably make the bet that there exist certain 24-bit sound files that certain listeners can discern from the same sound file that has been downsampled to 16-bit.

I would take you up on that bet. This has been tried before, and no difference was found, even when dithering wasn't used! The noise floor on 16 bit audio is around -96dB. There are very few HiFi systems that can manage that. Even in the highly unlikely event that there are listeners that can distinguish it, it's likely any difference will end up eliminated by noise in the analog components.

Re: 24/192 music downloads are silly

#136

Post by RogerL »

hamiltonkibbe wrote: post #99
xorcist wrote: post #95

Earlier quoted context omitted.

I don't understand what you mean, so I can't say you're wrong, but higher frequencies are not more quantized than low. In fact, you should be very careful about to think about quantization in digital sound reproduction, because it can easily lead you astray. Think of bit depth as a measure of dynamic range. Do look at that digital music primer for geeks posted elsewhere in this thread, it makes for awesome reading.

He was referring to the specific example he gave in which the higher-frequency had an amplitude of 2^6 and the lower frequency sinusoid had an amplitude of 2^10

And that is not how digital sampling works - you don't allocate bits to different frequencies.

Re: 24/192 music downloads are silly

#137

Post by derf_ »

KeytarHero wrote: post #104

24/192 playback isn't entirely silly. It's probably true that you can't hear a difference between a perfectly reconstructed 16/44.1k audio and perfectly reconstructed 24/192k audio. But the quality of your DAC certainly does matter, as well as the analog hardware that's after it. If a device has a 24/192k DAC, it means the manufacturer didn't just use the cheapest DAC they could find, and it's more likely to be high-…

Did you read the article?

"The ultrasonics are a liability during playback.... Neither audio transducers nor power amplifiers are free of distortion, and distortion tends to increase rapidly at the lowest and highest frequencies. ...any nonlinearity will shift some of the ultrasonic content down into the audible range as an uncontrolled spray of intermodulation distortion products covering the entire audible spectrum. Nonlinearity in a power amplifier will produce the same effect."

I would not expect a willingness to exploit consumers' magical thinking to be a good signal for quality engineering.

Re: 24/192 music downloads are silly

#138

Post by hackinthebochs »

kazinator wrote: post #126
sillysaurus3 wrote: post #60

Earlier quoted context omitted.

The correct way to attack this isn't by attacking the theory. It's to gather a lot of people and ask them to press a button indicating whether the audio they hear is 16-bit or 24-bit. If the results are no better than chance, then 24-bit doesn't matter, regardless of how sound the underlying argument is. EDIT: The experiment would also be extremely difficult to design. For example, you'd need to run this test with mu…

24 bit resolution is important for capture, because it leaves headroom for mistakes. 16 bits is enough for mastering.

There's also headroom for the signal processing in the equipment. Equalization or volume control done poorly can lower your dynamic range, for example when turning the volume down on windows then turning it up on an external amp.

Re: 24/192 music downloads are silly

#139

Post by aidenn0 »

Wicher wrote: post #131
masklinn wrote: post #30

Earlier quoted context omitted.

> Some people buy $500 wooden knobs to make their volume pots sound better. (or was that a hoax? i can't tell anymore) Some people buy small pyramids to elevate their cables off the floor, some people buy mats to put onto your CDs before putting the CD in a player ( http://dagogo.com/millenniums-m-cd-mat-carbon-cd-damper-revi... ), some people buy $1000+/meter digital interconnect cables ( http://www.theabsolutesound…

> some people buy mats to put onto your CDs before putting the CD in a player An 80-minute, 700 MB CD-R fits 80 * 60 * 44100 * 2 * 2 / 2^20 ~= 807 MB of audio. Why is that? The 100MB difference is not just due to the audio TOC being of smaller size than the ISO9660 or UDF file system metadata. It's also because of differences in error correction. I don't have the spec on hand but I recall from when I was investigatin…

On a decent drive, cdparanoia should successfully rip with no errors on a clean disc. I have done the md5sum test before.

Re: 24/192 music downloads are silly

#140

Post by aidenn0 »

anigbrowl wrote: post #124
threeseed wrote: post #78

Earlier quoted context omitted.

> Self-styled audiophiles are, by and large, idiots with way too much money plagued by magical thinking. Not just that. But the arrogance and fanboyism is rampant. God forbid you ever consider buying a Bose or Beats product.

Those are low-budget audiophile products, ie they are still marketed mainly to boost the ego of purchasers. There are three brands of headphones that pros use: Beyerdynamic (typically DT-100 or DT-770), Sennheiser (typically HD-5/650) and Sony (typically MDR-7506/9). Beyerdynamics have somewhat better isolation so they're more popular in music studios, Sonys are more comfortable when you have to wear them all day so…

What's different between the $80 7506 and $200 7509?
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