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24/192 music downloads are silly

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Re: 24/192 music downloads are silly

#151

Post by badsock »

diydsp wrote: post #41

I agree with the silliness of 192kHz, but not 24-bits. Here is why: In typical PCM recordings, like CDs, mid-range frequencies (e.g. 1kHz to 4kHz) are recorded with lower amplitudes because our ears are more sensitive to them. Sampling theory is correct and 16-bits can reproduce any waveform with ~100dB of range, however, in a complex waveform consisting of low, mid and high frequencies, the mid- and hi-range frequen…

If you're playing a 16 bit PCM at a reasonable listening level of 85dB SPL, then your 6 bit sinusoid is at 25dB SPL, which is quieter than a whisper at 6 feet away in a library. The quantization noise floor of a 6 bit recording is a further ~30dB quieter.

So, the noise of that signal is -5dB SPL. 0dB SPL was set to be the lowest possible perceivable level of a single sound in an aechoic chamber. And that's not even considering other sounds in the recording, or ambient noise levels in a typical living room, etc.

In your example, moving to 24 bit would been a long way from having any effect (other than a 50% increase in file size). And if you use, say, an 8 bit signal as an example, then things are even less noisy. Note that the noise is the only consideration here: any fidelity loss is represented in that figure.

The audio engineers of yore who (among other things) decided that 16 bits was more than enough for final mixdown were much more competent than they get credit for (many were downright amazing at what they did, in fact). They thought of stuff like this.

Re: 24/192 music downloads are silly

#152

Post by hamiltonkibbe »

RogerL wrote: post #136
hamiltonkibbe wrote: post #99

Earlier quoted context omitted.

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.

I don't think anyone is arguing that you do, the high-frequency sinusoid he described has a peak-to-peak amplitude of 2 * UINT6_MAX (although it appears as though the intention was a sinusoid with a p-p amplitude of UINT6_MAX) which on its own (in terms of the integer numbers given in his example) be represented in a 6-bit system. This isn't really relevant though, because that signal would be 0dBFS in a 6-bit system. The higher 10 bits are far from unused by the sinusoid in a 16 bit system, as they allow the amplitude of the sinusoid relative to the other sinusoid to remain unchanged. The little stairstep digitally-sampled sinusoid picture might look a little more rough for the "6-bit" sinusoid than the "10-bit" sinusoid but that's A)kind a pathological case and B)not at all representative of what gets sent to the amplifier after the DAC. (Think about the spectrum of all those little "stairsteps" and what happens to them once they are sent across a shunt capacitor...) anyways

Re: 24/192 music downloads are silly

#153

Post by bsder »

hackinthebochs wrote: post #143
diydsp wrote: post #41

I agree with the silliness of 192kHz, but not 24-bits. Here is why: In typical PCM recordings, like CDs, mid-range frequencies (e.g. 1kHz to 4kHz) are recorded with lower amplitudes because our ears are more sensitive to them. Sampling theory is correct and 16-bits can reproduce any waveform with ~100dB of range, however, in a complex waveform consisting of low, mid and high frequencies, the mid- and hi-range frequen…

192kHz may not be as silly as you think: http://www.ncbi.nlm.nih.gov/pubmed/10848570

Except that high frequencies attenuate fairly quickly in air.

Sound attenuates proportional to f^2 in air. So, a 10-fold increase in frequency causes a 100-fold increase in attenuation. So, a 100KHz signal has 10,000 times the attenuation for a 1KHz signal over the same range.

In addition, attenuation due to water vapor is particularly bad above about 40KHz. Much of that study cannot be replicated, and people have tried: http://en.wikipedia.org/wiki/Hypersonic_effect

In addition, the effect went away when using headphones.

However, I can certainly believe that if you can pump enough energy to rattle things at ultrasonic frequencies you are going to get a result. Especially since ultrasonic frequencies rattle in water particularly effectively.

As an example, if I pump enough energy into an ultraviolet or infrared signal at your eye I will eventually get a detection result in your brain. However, pain and a burned retina are not what we think about when we consider a brain response.

Re: 24/192 music downloads are silly

#154

Post by corford »

Cthulhu_ wrote: post #75

They're silly for listening maybe, but for editing (or so I gathered) they're quite valuable because the extra bits give editors a lot more room to play with the sounds and frequencies and such. It's not always about the audiophiles, you know.

Which the author mentions repeatedly in his post.

Re: 24/192 music downloads are silly

#155

Post by rspeer »

Monty's example files made me realize that my computer's sound chip is probably kind of lo-fi.

No, I couldn't hear anything in my headphones when I played the 30Khz/33Khz tones. In comparison, I heard something after it stopped. Somehow it was quieter during the playback.

Does it make any sense that my computer is better at making no audible sound when it's asked to play a loud inaudible sound, than when it's being asked to play nothing?

Re: 24/192 music downloads are silly

#156

Post by leoc »

ansible wrote: post #117
masklinn wrote: post #83

Earlier quoted context omitted.

Far from me the idea to defend them, but $350/m is about 3 times higher than Monster's most bullshitty bullshit cable. Even their "2000HD HyperSpeed HDMI cable" only had a $115/m MSRP in 5ft, falling to $32/m in 35ft: http://www.monsterproducts.com/Monster_Video_ISF_2000HD_Hype...

My great business idea was to produce a line of "organic" cables. Our company would go to the remote places of the earth to hunt down copper dragons (as in DnD) and harvest their veins to make audio cables. The "natural", "organic" copper has a warmth to the audio signals flowing through it that artificially produces cables just can't provide (they have harsher undertones). Then we'd also have silver and gold cables,…

PETA's going to bust your ass.

Re: 24/192 music downloads are silly

#157

Post by Wicher »

aidenn0 wrote: post #139
Wicher wrote: post #131

Earlier quoted context omitted.

> 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.

Background here:

http://www.xiph.org/paranoia/faq.html#play

Re: 24/192 music downloads are silly

#158

Post by TD-Linux »

hamiltonkibbe wrote: post #62
diydsp wrote: post #41

I agree with the silliness of 192kHz, but not 24-bits. Here is why: In typical PCM recordings, like CDs, mid-range frequencies (e.g. 1kHz to 4kHz) are recorded with lower amplitudes because our ears are more sensitive to them. Sampling theory is correct and 16-bits can reproduce any waveform with ~100dB of range, however, in a complex waveform consisting of low, mid and high frequencies, the mid- and hi-range frequen…

The resolution of both sinusoids in the example you suggest is exactly 16bits Edit: While it would be possible to represent each of those individual sinusoids in 6 and 10 bits individually, the signal you describe has the high frequency signal "riding on " the low frequency signal. you need 16 bits to represent the amplitude of that signal at e.g. t = pi/4.

2^10 + 2^6 = 1088. You only need 11 bits to not clip with that signal.

Re: 24/192 music downloads are silly

#159

Post by [deleted] »

chubot wrote: post #35
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…

It is baffling to me that people even talk about 24/192. There are such vast differences in audio quality related to speakers, loudness, amplifier, mastering, and EQ, before you even get to the source format. For some reason people seem to latch on to the format thing, before being able to make judgements about the more important factors.

[deleted]

Re: 24/192 music downloads are silly

#160

Post by donpark »

Sell to people what they want, not what you think they need. It's all about perception not whether there are basis behind the perception. Even Placebo effect needs equivalent of little pills as props. Higher the price, more they'll get out of the effect. If some nut can hear God's voice from a lump of rock costing $1M, who are we to take away his 'talent'?
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