24/192 music downloads make no sense • Hacker News Board

Re: 24/192 music downloads make no sense

#231

Post by rikkus » Sun, Nov 08, 2015, 10:45 PM UTC

semi-extrinsic wrote: post #209

Eiriksmal wrote: post #171

Earlier quoted context omitted.

Did some brief Googling to see if I could participate in a blind listening test and hear the difference between 24- and 16-bit recordings. I found this instead [0], an even more interesting gap to see if you can hear the difference between 8- and 16-bit! The source song, PSY's Gagnam Style, is the epitome of modern pop. I got a 3/10 on the listening test on a decent pair of Sennheiser headphones in a quiet room. Some…

With these online tests, can anyone shed some light on how browser/plugin codecs come into play? I recently took Tidal's test to see if I could distinguish their lossless Flac option from 320 kbps AAC. Using a decent DAC and some Sennheiser HD202's I managed to score 0/10, which is somehow impressive.

I believe in various tests no-one has been able to reliably discern lossless audio from 320kbps mp3, even though mp3 performs comparatively poorly at lower bitrates, compared to more modern lossy codecs.

Re: 24/192 music downloads make no sense

#232

Post by hatsunearu » Mon, Nov 09, 2015, 1:38 PM UTC

pizza234 wrote: post #43

earlz wrote: post #26

I can't hear a difference between 96khz/44khz in it's raw form. However, I can tell the difference from effects in audio mixing. The extra detail can really make a difference in how well an audio effect VST works. I have a 96khz/24bit interface that I use and ATH-M30X headphones, and I can tell a difference between at least some 24bit FLAC files and 16bit highest-quality-possible MP3s. I was mixing my own music and t…

Compressed formats are not really relevant to considerations about the bit depth itself. Besides, mp3 [audio] compressions have difficulty in handling specific samples, or type of samples (eg. sharp attacks), and they may manifest artifacts independently of the bitrate; MP3, AFAIK, also has a ceiling of 320 kbps within the standard specification, which certainly doesn't help. Secondly, I'm not sure if you process fur…

Old thread, but I thought I made it clear that I wasn't talking about data compression, but rather dynamic range compression.

Re: 24/192 music downloads make no sense

#233

Post by beat » Mon, Nov 09, 2015, 2:10 PM UTC

chillingeffect wrote: post #179

beat wrote: post #169

Earlier quoted context omitted.

I've played acoustic and electric instruments for over 30 years, and recorded numerous albums. Compression is the best tool we have for accurately reproducing the musicality and emotion of a musical performance. Without compression, most recordings would be unlistenable. Don't confuse the foolishness of the loudness wars for "compression is bad". That's like saying the internet is bad because there's porn on it.

I respect your opinion, but it's only your opinion, not a global truth. Compression is a style. There is far more to musicality and emotion than compression. The problem compression solves is that the environments where industrialized cultures now listen in are not dedicated listening areas, but alternately loud and quiet places, so compression makes all parts of the music almost equally loud so there are no drop out…

Compression is a tool, not a style. It has existed almost as long as recording itself. It solves fundamental problems.

Problem #1 - Audio speakers are not the same as instruments! If you've ever had the pleasure of getting your hair blown back by a cranked guitar amp or a drum kit... well, you just can't reproduce that experience through a set of earbuds. You can't exactly reproduce the sound of an acoustic guitar in your lap, or a violin in a beautiful hall. Speakers just aren't up to it. A recording is a miniature of a sound. Like all miniatures, it exaggerates some details and obscures others.

Second, most modern music consists of many instruments of different volumes and dynamic ranges played together. Mixing the sounds so everything sounds clear and balanced is extremely difficult. Some of the most important instruments are the worst about it - acoustic guitars and drum kits in particular walk all over everything else, with wide dynamic and frequency ranges that compete with steadier sounds. And certain harmonically-dense sounds like female vocals and violins can easily distort the audio amps used in reproduction. Compression, and its close cousin equalization, help engineers "carve" spaces for each instrument to live in.

You have probably never heard a recording without extensive compression, unless you've mixed records. And if you've been actively involved in recording, you'll already know all this.

Re: 24/192 music downloads make no sense

#234

Post by dTal » Mon, Nov 09, 2015, 3:32 PM UTC

lmm wrote: post #42

klodolph wrote: post #38

Earlier quoted context omitted.

24bit has been shown to be excessive in actual tests, and it doesn't really pass the "bullshit test". 24 bit allows you to switch between a whisper in a library and a jet engine or shotgun blast in a single recording—yes, it would instantly damage your hearing. By comparison, 16 bit audio can "only" record a whisper in a library and a motorcycle or jackhammer. Double blind tests show that 8 bits are not enough, but 1…

Citation? The article is talking about dithering, which you really don't want to do, not least because the end result will probably compress worse than the higher-bit-depth version. The fact that they suggest it at all implies, to my mind at least, that 16 bits isn't enough.

You absolutely do want to do dithering. Dithering converts distortion (error correlated with the signal, which is bad) to noise (error uncorrelated with the signal, which is less bad). This means that even though the noise floor is higher, you can recover more of the original signal. There is virtually no case where that is not desirable.

You're right of course that it will compress less well, but that's to be expected because you've lost less information!

Re: 24/192 music downloads make no sense

#235

Post by dTal » Mon, Nov 09, 2015, 3:36 PM UTC

criddell wrote: post #59

lawnchair_larry wrote: post #30

Earlier quoted context omitted.

Vinyl actually has far less fidelity. You also physically change the recording every time you play it back. Even on the same equipment, no two plays of a vinyl LP sound exactly the same, unlike digital. This fact alone should cause you to question your subjective experience. You have no idea what part of that system was contributing to what you found pleasant. Someone who knew what they were doing could probably buil…

> You also physically change the recording every time you play it back Not on a laser stylus turntable. http://diffuser.fm/laser-turntable/

These are not recommended for high-fidelity playback. They're good for archiving records you don't want to damage by playing, but the laser picks up every tiny speck of dust that a needle would plow inaudibly through.

Re: 24/192 music downloads make no sense

#236

Post by dTal » Mon, Nov 09, 2015, 4:09 PM UTC

lmm wrote: post #221

nullc wrote: post #181

Earlier quoted context omitted.

At 16 bits dithering is probably pointless for listening purposes. What dithering does is it decorrelates the quantization noise with the signal. Absent it, quantization generates harmonic spurs. In theory, on a very clean and noiseless signal these harmonic spurs might be more audible than you'd expect from the overall quantization level. In practice, 16 bits is enough precision that these harmonics are inaudible ev…

The article is saying you can use dithering to represent sounds quieter than your 16-bit "0000000000000001". That's what I'm objecting to.

Consider the case of a 1-bit image. Let's say the "signal" is a smooth gradient of black to white from one side of the image to the other. If you simply quantize to the nearest value, one half of the image ends up solid black and the other half, solid white. No amount of after-the-fact "dithering" of this image will recover the original gradient - it is lost forever.

Now supposing we add noise to our signal before we quantize. A given pixel at 25% gray (which under the previous scheme would always end up solid black) now has a 25% chance of ending up white. A contiguous block of such pixels will have an average value of 25% gray, even though an individual pixel can only be black or white. Thus, by flip-flopping between the two closest values ("dithering") in statistical proportion to the original signal, information is preserved.

https://en.wikipedia.org/wiki/File:1_bit.png

Re: 24/192 music downloads make no sense

#237

Post by some-guy » Mon, Nov 09, 2015, 5:47 PM UTC

lfam wrote: post #189

some-guy wrote: post #82

This article hits close to home: before I became a programmer I worked as an audio engineer at a fledgling studio in my hometown. The amount of misinformation / junk-science in the audio world is preposterous. There's a religious-cult of an industry that feeds off the ignorance and placebos of its participants. I have many friends who swear by their What.cd 24/192 FLAC vinyl rips and spend hundreds of dollars on audi…

In the case of sites like what.cd, I think that FLAC 16/44 rips of CDs and vinyl are useful for creating distributed backups of our cultural corpus. But I agree that 24/192 FLACs of vinyl are ridiculous.

I agree, in fact I very much like the sound of vinyl, but to say it's more "accurate" or of higher fidelity and dynamic range than 16/44 is completely false.

Re: 24/192 music downloads make no sense

#238

Post by shermanyo » Tue, Nov 10, 2015, 1:02 PM UTC

chillingeffect wrote: post #179

beat wrote: post #169

Earlier quoted context omitted.

I've played acoustic and electric instruments for over 30 years, and recorded numerous albums. Compression is the best tool we have for accurately reproducing the musicality and emotion of a musical performance. Without compression, most recordings would be unlistenable. Don't confuse the foolishness of the loudness wars for "compression is bad". That's like saying the internet is bad because there's porn on it.

I respect your opinion, but it's only your opinion, not a global truth. Compression is a style. There is far more to musicality and emotion than compression. The problem compression solves is that the environments where industrialized cultures now listen in are not dedicated listening areas, but alternately loud and quiet places, so compression makes all parts of the music almost equally loud so there are no drop out…

> Where can you find music with no compression?

the pub?

Re: 24/192 music downloads make no sense

#239

Post by lmm » Tue, Nov 10, 2015, 1:22 PM UTC

dTal wrote: post #234

lmm wrote: post #42

Earlier quoted context omitted.

Citation? The article is talking about dithering, which you really don't want to do, not least because the end result will probably compress worse than the higher-bit-depth version. The fact that they suggest it at all implies, to my mind at least, that 16 bits isn't enough.

You absolutely do want to do dithering. Dithering converts distortion (error correlated with the signal, which is bad) to noise (error uncorrelated with the signal, which is less bad). This means that even though the noise floor is higher, you can recover more of the original signal. There is virtually no case where that is not desirable. You're right of course that it will compress less well, but that's to be expect…

Or because you've added randomness?

Store the 24-bit signal, and you could do a dithered downsample to 16-bit on playback if you think that's a good idea. Wouldn't that be better all round?

Re: 24/192 music downloads make no sense

#240

Post by lmm » Tue, Nov 10, 2015, 11:06 PM UTC

dTal wrote: post #236

lmm wrote: post #221

Earlier quoted context omitted.

The article is saying you can use dithering to represent sounds quieter than your 16-bit "0000000000000001". That's what I'm objecting to.

Consider the case of a 1-bit image. Let's say the "signal" is a smooth gradient of black to white from one side of the image to the other. If you simply quantize to the nearest value, one half of the image ends up solid black and the other half, solid white. No amount of after-the-fact "dithering" of this image will recover the original gradient - it is lost forever. Now supposing we add noise to our signal before we…

Sure, I know how it works. But it sacrifices resolution (spatial in this example, temporal in the case of audio) and compresses poorly. Rather than dithering, you should use a higher bit depth so that you can represent your original gradient (with the desired smoothness) directly.