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24/192 music downloads are silly

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Re: 24/192 music downloads are silly

#221

Post by jongraehl »

cjensen wrote: post #206

The author confuses sampling theory with reality. Sampling theory says you can reconstruct a signal by sampling it at least twice per cycle. So 44.1KHz is an adequate sampling rate for an 22.05Khz signal. Unfortunately to make Digital-to-Analog conversion work according to theory, you must first construct an ideal analog filter which filters out everything above 22.05Khz while leaving everything less than 22.05Khz un…

Author is an expert, and correct. In the linked video he mentions that the difficulty of creating a sharp analog high-pass filter is in practice completely mitigated by oversampling, which is described in the Wikipedia article on DACs.

Suppose you have a 96khz DAC coming from your computer. Surely you see that a computer can solve for the nyquist reconstruction of some lower sample-rate recording (e.g. CD audio) to that sample rate, and then (still in digital 96khz) remove ALL the noise between say 21khz and 96khz, at which point a final analog filter will have an easy time leaving 0-21khz unmolested while killing all higher frequencies, right? It's practically implied by what you wrote. Per what OP says, that's more or less the effect of any DAC you'll use today.

Re: 24/192 music downloads are silly

#222

Post by harshreality »

nkurz wrote: post #148
aidenn0 wrote: post #135

Earlier quoted context omitted.

> 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 unlike…

I probably should have written 16/44.1 vs 24/192, since I was thinking mostly of the waveform 'beat' interactions as shown in the linked video. Do you feel those are also indistinguishable? I can't afford an actual bet on it, but I'm interested enough to explore a bit and see what I can find.

Unless your listener can hear frequencies above 22.05kHz, it's theoretically impossible because the sampling theorem says 44.1kHz sampling can perfectly reproduce all frequencies below 22.05kHz.

Any differences within normal human audible frequency ranges must be caused by imperfect DAC. Agreed?

(No, I don't have a perfect DAC, but if the audible artifacts are because of a DAC that produces less perfect analog waveforms below 22kHz when fed a 44kHz source rather than a 192kHz source, isn't that squarely the DAC's fault? It should also be made abundantly clear that this is a hypothetical. Is this actually a problem? Has anyone simulated an analog waveform from 44.1kHz sample, compared it to oscilloscope readings from a decent quality DAC, and noticed theoretically audible differences?)

Re: 24/192 music downloads are silly

#223

Post by dcohenp »

storrgie wrote: post #218
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…

When someone spends money on something in a silly way, do you consider them to be an idiot? Would you make the same statement about someone who spends 200$ on a bottle of scotch versus buying a 35$ bottle? Let the 'idiots' spend their money driving an industry that is combining the creation of electronics with functional art. I'm not sad to see a $40,000 DAC. I don't have to buy it, and it's cool to know someone buil…

It's one thing when you plop down a ton of cash for something where you embrace the "silliness" or whatever makes it special (e.g. buying exotic cars with monstruous engines to drive them into traffic). It's another, however, believing something is objectively "better" because it cost more; e.g. spending money on Monster Cables thinking you can hear a difference.

In audio, you have people who love vinyl because they enjoy the distortion it makes, and that's perfectly fine; but you have others who somehow believe it sounds closer to the original, which is demonstrably ridiculous.

Re: 24/192 music downloads are silly

#224

Post by pokpokpok »

storrgie wrote: post #218
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…

When someone spends money on something in a silly way, do you consider them to be an idiot? Would you make the same statement about someone who spends 200$ on a bottle of scotch versus buying a 35$ bottle? Let the 'idiots' spend their money driving an industry that is combining the creation of electronics with functional art. I'm not sad to see a $40,000 DAC. I don't have to buy it, and it's cool to know someone buil…

I would make the argument that if some of the silliness was stated for what it was, gullible rich people would spend their money on something equally frivolous that did more to drive innovation

Re: 24/192 music downloads are silly

#225

Post by vegedor »

cjensen wrote: post #206

The author confuses sampling theory with reality. Sampling theory says you can reconstruct a signal by sampling it at least twice per cycle. So 44.1KHz is an adequate sampling rate for an 22.05Khz signal. Unfortunately to make Digital-to-Analog conversion work according to theory, you must first construct an ideal analog filter which filters out everything above 22.05Khz while leaving everything less than 22.05Khz un…

>Sampling theory [the nyquist theorem] says you can reconstruct a signal by sampling it at least twice per cycle. So 44.1KHz is an adequate sampling rate for an 22.05Khz signal.

I mean, if we wanna be nitpicking. I've seen many get it slightly wrong, and I'm not even sure myself. So, honest question: If you'd sample a 22.05Khz sinus signal at the zero crossings, you could tell the difference to silence?

For sure, it's enough for anything below half the sample-rate.

Re: 24/192 music downloads are silly

#226

Post by aaronem »

esaym wrote: post #210
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…

I don't know about comparing digital to digital, but I know I can tell the difference between a 320kbs mp3 and a good quality LP record. Its in the treble. I guess any kind of digital just ruins that.

Yeah, that's an easy difference to spot -- LP playback is just so lossy, with so much artifacting, that it's just not worth the bother.

Re: 24/192 music downloads are silly

#227

Post by ansible »

sillysaurus3 wrote: post #116
ansible wrote: post #112

Earlier quoted context omitted.

The experiment would also be extremely difficult to design. I disagree. I think all the factors you are concerned about can be eliminated with a large enough sample size, like in the thousands (or maybe 10s of thousands). You allow each person to select the genre of music they like, and you play a few clips from a few songs of each bitrate. Then they guess which is 24-bit and which is 16-bit. I'm not paying to set it…

Pretend your headphones only moved with 8-bit resolution. There is no possible way the experiment could derive a useful conclusion, but you might trick yourself into thinking it did. Especially if your sample size was 10,000 people. More realistically, the participant might choose music for which no 24-bit recording exists. It's very important to control for every variable. It's actually not possible to gather info a…

More realistically, the participant might choose music for which no 24-bit recording exists.

Well, obviously we'd need to have a limited set of music selections for which we have 24-bit recordings.

As you suggest, I expect the biggest impact on playback fidelity is going to be other factors like the noise in the system (likely a PC) and such.

But the flip side of it is that's also a good real world test. If the only time you can tell a difference is to be in an acoustically dead room with top end equipment, then the higher sample rate really isn't worth it.

Re: 24/192 music downloads are silly

#228

Post by Lazlo_Nibble »

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…

Uh, no. Bit-perfect ripping is trivial and routine, and tools like the AccurateRip DB (which has checksums for around three million different titles you can use to verify the checksums on your own rips) and the CUEtools database (which has recovery records you can use to correct bit errors on your own rips) prove it. I routinely get bit-accurate single-pass high-speed rips--no "paranoid" settings or re-reads--of discs dating back thirty years or more, and so do hundreds of thousands of other people. If you get different checksums on successive rips of the same CD, either the disc is damaged or the drive you're using is failing.

Re: 24/192 music downloads are silly

#230

Post by dfox »

cjensen wrote: post #206

The author confuses sampling theory with reality. Sampling theory says you can reconstruct a signal by sampling it at least twice per cycle. So 44.1KHz is an adequate sampling rate for an 22.05Khz signal. Unfortunately to make Digital-to-Analog conversion work according to theory, you must first construct an ideal analog filter which filters out everything above 22.05Khz while leaving everything less than 22.05Khz un…

Typical way to get around the requirement of steep reconstruction filter is oversampling just before the DAC, which is something that was done even by earliest CD players, today in most cases audio DACs are sigma-delta which is essentially oversampling taken to the extreme, that causes that reconstruction filter is mostly irrelevant for output audio quality and is there only for EMC reasons.

It's kind of funny that typical DIY audiophile-grade DAC constructions use some R-2R DAC without oversampling and thus need significantly steeper reconstruction filters.

Overall point is that you don't need to store and more importantly transfer the additional data because they do not contain any useful information.

As for the jitter, I somehow don't believe it is as significant problem as it is often presented, but anyway it's perceived effects should be mostly independent of sample rates and sample sizes.

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