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Topic: Why 24bit/48kHz/96kHz/ (Read 392192 times) previous topic - next topic
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Why 24bit/48kHz/96kHz/

Reply #152
I'm a PC modder, and I'll do all sorts of things to get my PC to run faster and cooler and with more lights in it.  I have benchmarks and tests that will show just how much faster my PC is than other people's.  Numbers!  Never mind that it's physically impossible to tell, from the user's point of view, whether you're going at 29.4 fps or 31.2 fps in a game.  But if I was to sell you a graphics card I'd gloss over that, give you the numbers, and you would decide for yourself that the one that goes faster is the better one.  Apart from cost, what real difference is it going to make to your life?  Only one : it will make you feel better.  Your experience of playing a game will be better.  It's subjective, but you'll have more fun knowing that you're not losing out to the limitations of your own optical nerves, which can only detect rates up to 25fps or thereabouts.  So : should progress of graphics technology be stopped, because it's "good enough"?  Of course not.


On a PC it does matter how fast can it go or how much info it can process. Getting 200fps on X game might not be noticeable, but in the near future there will be a more demanding Y game that will get you roughly 20fps.

It is not the same with audio, indeed you can improve the sound card, but there's no point in improving it to the point where the difference is impercetible or negligible if you know that the future will not demand any more.

I don't see a problem with 96kHz/24-bit either, but it is much like killing a flea with a cannon.

Why 24bit/48kHz/96kHz/

Reply #153
The words ''sound better'' should not be used to describe sensations that have nothing to do with hearing.

Why 24bit/48kHz/96kHz/

Reply #154
24 FPS was chosen because it was the lowest number to provide smooth-enough moving images. When there is a lot of movement in a scene, it becomes very easy to notice the jerkyness. Especially in a cinema.

In fast-paced computer games, 25fps equals unplayable for me. I seem to need about 40 as a minimum. Let's do some math. A fast turn at high mouse sensitivity can easily be ~500 degrees per second. At 25fps this equals 20 degrees per frame, with a FOV of 100 this means a displacement of 1/5th of your screen. Your eyes will have a lot of trouble tracking a moving object at such a low granularity. Framerates much higher than those needed for smooth images can also serve a purpose as it reduces processing latency, which can make a difference when everyone is playing at their limits, like in cyberathletics.

I can tell the refresh rate of a monitor when it's displaying a light surface, up to about 85Hz. When servicing computers i try to guess the screen's refresh rate before checking it. I'm nearly always right. Not a double blind test but as good as it gets.  LCD's are excempt from this of course, but at the right angle in direct sunlight, i've seen the old style LCD screens of digital watches flicker also. Curiously enough i can also notice some plasma screens refresh like TV's. Spotting the 100HZ tv's in a tv store is pretty easy also.


Sound isn't video, however.
Veni Vidi Vorbis.

Why 24bit/48kHz/96kHz/

Reply #155
While its a whole different argument, I agree with the above post - that while 24fps may be the cinemas moving image benchmark, its not the limit of visual perception by any means whatsoever.

In the same way that 128kbit mp3 is not "CD Quality" audio, however it is suitable for the general populous with mobile mp3 players.

EG:
I bought 2 albums on itunes, 128kbit AACs, and they sound terrible. The album in question is Less than Jake (trumpets sound ok, but the cymbals sound like gravel in my ears)

I also can tell (also used to be video technician for Digital Video Computing in sussex, UK) the difference between 50hz, and 75hz for example, and between 75 and 85 (gets harder), between 85 and 100 is difficult though - although I think i would get reasonable results in double blind tests.

But noone is saying that CD audio is DVD-A quality.

They are saying that noone can scientifically prove that they can tell a difference.

But thats like saying a gherkin is a good gherkin:
how many gherkins have you tried? what kind of vinegar are they pickled in? How long have they been pickled for? did you read the label before tasting and voting on it?

Frankly I dont give a damn - I know a good gherkin when i taste one, and i know a bad one too.

I think 96khz 24bit is a good place to stop for audio, because I don't see why we should have the accuracy/reproduction of an analogue source limited in any way. The mathematical proof is - that DVD-A is far better when mixed down from an analogue recording session.

infinite wave sampled to  CD Quality

is an exponentially poorer reproduction

than sampling @ DVD-a quality.


Enough of the abx blind tests.....they are subjective.....YOU are listening through your EARS.  Just liek I did - i couldnt tell the difference, but I say, when we have a lot of cannons, and cannonballs, lets kill fleas with em!!!!
Gone.

Why 24bit/48kHz/96kHz/

Reply #156
You are not killing fleas, you are shooting holes in the air. And in your wallet.
"We cannot win against obsession. They care, we don't. They win."

Why 24bit/48kHz/96kHz/

Reply #157
I think 96khz 24bit is a good place to stop for audio, because I don't see why we should have the accuracy/reproduction of an analogue source limited in any way. The mathematical proof is - that DVD-A is far better when mixed down from an analogue recording session.

infinite wave sampled to  CD Quality

is an exponentially poorer reproduction

than sampling @ DVD-a quality.


Analog recordings don't have infinate resolution, if thats what you're trying to say. 

Even ignoring that, saying something is a "mathematical proof" is meaningless if you neglect to include the actual math!

Why 24bit/48kHz/96kHz/

Reply #158
Analog recordings don't have infinate resolution, if thats what you're trying to say. 

Even ignoring that, saying something is a "mathematical proof" is meaningless if you neglect to include the actual math!


Alright they are limited by the accuracies of the voltage applied to the magnetic head during recording, and the quality/thicknes/width/age of the tape, which in turn is limited by the musical signal you are recording to the tape etc. etc. blah..... Jeez, there are literally billions of factors affecting it, but at least they also affect digital recording excluding the voltage/current accuracies applied to the recording head and the efficiency and response curve of the recording head.

I didnt do any maths to prove that 1 to the power of 16 is exponentially smaller dynamic resolution than 1 to the power of 24, now are you happy that ive wasted 2 minutes telling you what you already should know to be posting comment in this thread? Go look up "exponential" and prove it yourself.

poking holes in my post while not addressing the point is a classic strawman argument - congratulations.
Or are you suggesting that its not exponentially a poorer representation? No - you didnt do that - just poked holes to make it SEEM like my point held no water. I don't like that - its childish and totally unscientific. Go away.

ITs friday - im hot, at work, and i was just making a point without POINTLESSLY DELVING into UNNECESSARY DETAILS.
Gone.

Why 24bit/48kHz/96kHz/

Reply #159
I didnt do any maths to prove that 1 to the power of 16 is exponentially smaller dynamic resolution than 1 to the power of 24, now are you happy that ive wasted 2 minutes telling you what you already should know to be posting comment in this thread? Go look up "exponential" and prove it yourself.

In my math book 1^16 = 1^24. 

I assume you mean 2^16 < 2^24.

But the question is if the extra resolution will bring you anything you can hear. And a higher dynamic range might help a little in very extra-ordinary cases. But a higher sampling rate won't. But if you have nothing better to spend your money on, go ahead.
"We cannot win against obsession. They care, we don't. They win."

Why 24bit/48kHz/96kHz/

Reply #160

I didnt do any maths to prove that 1 to the power of 16 is exponentially smaller dynamic resolution than 1 to the power of 24, now are you happy that ive wasted 2 minutes telling you what you already should know to be posting comment in this thread? Go look up "exponential" and prove it yourself.

In my math book 1^16 = 1^24. 

I assume you mean 2^16 < 2^24.

But the question is if the extra resolution will bring you anything you can hear. And a higher dynamic range might help a little in very extra-ordinary cases. But a higher sampling rate won't. But if you have nothing better to spend your money on, go ahead.


pwned.

I told ya it was a friday!!!! and it really is hot in my office..... hahaha

I agree with you essentially, but my point is - why not? when we can make cd players that read dvd-a as well? I don't see.....my hard drive is now 320+160 gigabytes, almost a half terabyte. My first HD was 40 MEgabytes!!!

As long as the production takes advantage of it at every stage, then i think its worth doing as a last step to arguably transparent digital sampling.
Gone.

Why 24bit/48kHz/96kHz/

Reply #161
...


This is the scientific discussion forum. You are posting speculation(s), which are useless in this context, and parts of your post where you make audible claims without acceptable perceptual tests to back them up, may actually be a violation of the TOS of this website.

-Chris

Why 24bit/48kHz/96kHz/

Reply #162
The reason we need more than 16 bit audio is because the human ear can hear through the noise floor level.  This is easily proven by yourself.  Go to a crowded party where the noise level is very high.  If you couldn't hear below this noise level, a private conversation between two people would be inaudible over the noise.  Imagine if suddenly one of them mentions your name in a less than complimentery way.  Suddenly, all the noise in the room is now quiet, and you can hear every word they say, even though they were noise previously.  Human hearing is like that.  Now imagine that you are listening to a band with several voices, and in the background is a tune that is being played very softly, but that is what you want to hear.  If the bit level is deep enough, you will be able to tune it in, otherwise, it is just interference to the main sound level.  I wish we had 32 bit/64KHz stereo minimum for all recordings, that would do justice to any music.
This is my first post.  The people here seem very educated.  I am educated too, but I am not an engineer or sound technician.  This is my personal opinion, but I wish that the subject of sound reproduction wasn't so cold and clinical, too many assumptions are made that make cold clinical sense, but not sense if you factor in the human element.  The subject of not being able to hear below the noise floor is a perfect example.

Why 24bit/48kHz/96kHz/

Reply #163
The reason we need more than 16 bit audio is because the human ear can hear through the noise floor level.  This is easily proven by yourself.  Go to a crowded party where the noise level is very high.  If you couldn't hear below this noise level, a private conversation between two people would be inaudible over the noise.  Imagine if suddenly one of them mentions your name in a less than complimentery way.  Suddenly, all the noise in the room is now quiet, and you can hear every word they say, even though they were noise previously.

Your argument-chain is invalid, because you are mixing up *MASKING* and Noise-Floor. Both are by far not the same. The fact that we can change "how we filter information" has nothing to do with the noise-floor. This is an argument from ignorance.

- Lyx
I am arrogant and I can afford it because I deliver.

Why 24bit/48kHz/96kHz/

Reply #164
The reason we need more than 16 bit audio is because the human ear can hear through the noise floor level.  This is easily proven by yourself.  Go to a crowded party where the noise level is very high.  If you couldn't hear below this noise level, a private conversation between two people would be inaudible over the noise.  Imagine if suddenly one of them mentions your name in a less than complimentery way.  Suddenly, all the noise in the room is now quiet, and you can hear every word they say, even though they were noise previously.  Human hearing is like that.  Now imagine that you are listening to a band with several voices, and in the background is a tune that is being played very softly, but that is what you want to hear.  If the bit level is deep enough, you will be able to tune it in, otherwise, it is just interference to the main sound level.  I wish we had 32 bit/64KHz stereo minimum for all recordings, that would do justice to any music.

I don't understand, why this should be an argument for the need of higher bit resolutions. Perception can be selective, that is true. The selection here can be made by special properties of the signal (Frequency, patterns, the meaning it has for you...). But why should you need a high bit resoulution or dynamics to perform this selection? This would only be true, if the dynamic range would be too small to let you discriminate the properties you need for your selection process. I am quite sure, that for your examples even far less than 16 bit would be sufficient to perform the selection.

Why 24bit/48kHz/96kHz/

Reply #165
Let's take a cold clinical approach to the example you have presented here:
Go to a crowded party where the noise level is very high.  If you couldn't hear below this noise level, a private conversation between two people would be inaudible over the noise.  Imagine if suddenly one of them mentions your name in a less than complimentery way.  Suddenly, all the noise in the room is now quiet, and you can hear every word they say, even though they were noise previously.

The SPL of a crowded party that is loud is probably no more than 95dB, 105dB tops with loud music going.

The SPL of a "whisper" that can be heard between two people at such a party will be no less than 35dB.

The difference between these levels is at most going to be 70dB.  The SNR due to the quantization noise of 16 bits is 96dB, more than enough to capture that whisper at a noisy party.

Why 24bit/48kHz/96kHz/

Reply #166
While you are right that the SNR of the quantization noise of a 16 bit signal is 96dB, keep in mind that we're talking about the *quality* of the quietest sound.  So if this quietest sound was at -96dB, then it would have no quality at all because it would be a square wave.

The real question should be "what bit resolution is necessary *FOR THE QUIESTEST SOUND*."  At 16 bits, the quiet sounds are audible, but they don't have the same detail as the louder sounds.

  Now check this out.  You can get 24 bit audio from 16 bit CDs - how?  Use ogg vorbis at a very high quality level.  The file now contains *frequency* domain information.  That means that if there is quantization, it will disappear with a decoder running at 24 bit accuracy.

You could still do a lot of other things wrong.  I use Shure E5C headphones driven with a custom Sigma delta converter and amp.  Things are real clean and real quiet.  The difference between 16 bit and 24 bit is just OBVIOUS.  Especially quiet sounds with some texture, like the echos after a background percussion hit.


The reason we need more than 16 bit audio is because the human ear can hear through the noise floor level.  This is easily proven by yourself.  Go to a crowded party where the noise level is very high.  If you couldn't hear below this noise level, a private conversation between two people would be inaudible over the noise.  Imagine if suddenly one of them mentions your name in a less than complimentery way.  Suddenly, all the noise in the room is now quiet, and you can hear every word they say, even though they were noise previously.  Human hearing is like that.  Now imagine that you are listening to a band with several voices, and in the background is a tune that is being played very softly, but that is what you want to hear.  If the bit level is deep enough, you will be able to tune it in, otherwise, it is just interference to the main sound level.  I wish we had 32 bit/64KHz stereo minimum for all recordings, that would do justice to any music.

I don't understand, why this should be an argument for the need of higher bit resolutions. Perception can be selective, that is true. The selection here can be made by special properties of the signal (Frequency, patterns, the meaning it has for you...). But why should you need a high bit resoulution or dynamics to perform this selection? This would only be true, if the dynamic range would be too small to let you discriminate the properties you need for your selection process. I am quite sure, that for your examples even far less than 16 bit would be sufficient to perform the selection.

Why 24bit/48kHz/96kHz/

Reply #167
While you are right that the SNR of the quantization noise of a 16 bit signal is 96dB, keep in mind that we're talking about the *quality* of the quietest sound.  So if this quietest sound was at -96dB, then it would have no quality at all because it would be a square wave.

The real question should be "what bit resolution is necessary *FOR THE QUIESTEST SOUND*."  At 16 bits, the quiet sounds are audible, but they don't have the same detail as the louder sounds.

That is a strawman argument and, in fact, is not the question.

Clearly, if you want to encode a signal using only the least significant bit, you will have large amounts of distortion - after all, it's a 1-bit signal. But those signals simply do not exist in real life. The most important reason is that nobody would want to listen to actual music on it - there's no known listening environment, or set of listeners, that can tolerate more than 60db of dynamic range. There is also no popular or classical music with 90db of dynamic range.

I don't think you are able to come up with a valid use case where the quantization noise is actually important, unless you want to cause permanent hearing loss in the listener. If you wanted to record the Space Shuttle taking off, then sure, you'd probably need 24 bits of precision. But that has no bearing on the use of CDs to store actual music, or failing that, sounds that people really want to listen to.

Quote
Now check this out.  You can get 24 bit audio from 16 bit CDs - how?  Use ogg vorbis at a very high quality level.  The file now contains *frequency* domain information.  That means that if there is quantization, it will disappear with a decoder running at 24 bit accuracy.

You are confusing "accuracy" with "precision". Look it up. You will never get better than 16 bits of accuracy out of CD, even if you decode to 64-bit floating point, no matter which format you use.

Why 24bit/48kHz/96kHz/

Reply #168
So if this quietest sound was at -96dB, then it would have no quality at all because it would be a square wave.


Please go to a good reference library and read Bart Locanthi Sr's paper on dithering.

Thank you.
-----
J. D. (jj) Johnston

Why 24bit/48kHz/96kHz/

Reply #169

So if this quietest sound was at -96dB, then it would have no quality at all because it would be a square wave.


Please go to a good reference library and read Bart Locanthi Sr's paper on dithering.

Thank you.


heh that was my thought.  You can do a lot with just one bit.  Certainly more then a "square wave".

Why 24bit/48kHz/96kHz/

Reply #170
heh that was my thought.  You can do a lot with just one bit.  Certainly more then a "square wave".
I tried to point that out to someone here once but it didn't go over too well.

http://www.hydrogenaudio.org/forums/index....&pid=414672

Why 24bit/48kHz/96kHz/

Reply #171
Quote
Clearly, if you want to encode a signal using only the least significant bit, you will have large amounts of distortion - after all, it's a 1-bit signal. But those signals simply do not exist in real life. The most important reason is that nobody would want to listen to actual music on it - there's no known listening environment, or set of listeners, that can tolerate more than 60db of dynamic range. There is also no popular or classical music with 90db of dynamic range.


This is true under practical conditions. 
budding I.T professional

Why 24bit/48kHz/96kHz/

Reply #172
The real question should be "what bit resolution is necessary *FOR THE QUIESTEST SOUND*."


Answer : 1 bit, because the quietest audible sound by the ear has no quality either.

Now check this out.  You can get 24 bit audio from 16 bit CDs - how?  Use ogg vorbis at a very high quality level.  The file now contains *frequency* domain information.  That means that if there is quantization, it will disappear with a decoder running at 24 bit accuracy.


No. Quantization introduces noise. When you decode at 24 bits, you still have got the 16 bits noise introduced by the ADC process. It doesn't disappear. It is encoded and decoded.

The difference between 16 bit and 24 bit is just OBVIOUS.  Especially quiet sounds with some texture, like the echos after a background percussion hit.


Please, provide ABX results.

Why 24bit/48kHz/96kHz/

Reply #173
Quote
Clearly, if you want to encode a signal using only the least significant bit, you will have large amounts of distortion - after all, it's a 1-bit signal. But those signals simply do not exist in real life. The most important reason is that nobody would want to listen to actual music on it - there's no known listening environment, or set of listeners, that can tolerate more than 60db of dynamic range. There is also no popular or classical music with 90db of dynamic range.


This is true under practical conditions. 



Really, if I encode a signal with a massively oversampled 1-bit signal, I'll get large amounts of distortion?

***cough***

Really?????

I use Shure E5C headphones driven with a custom Sigma delta converter and amp.  Things are real clean and real quiet.  The difference between 16 bit and 24 bit is just OBVIOUS.  Especially quiet sounds with some texture, like the echos after a background percussion hit.

(Emphasis added)

That's a pretty good 1-bit system, now, isn't it?
-----
J. D. (jj) Johnston

Why 24bit/48kHz/96kHz/

Reply #174
[...]

Really, if I encode a signal with a massively oversampled 1-bit signal, I'll get large amounts of distortion?

***cough***

Really?????

[...] (Emphasis added)

That's a pretty good 1-bit system, now, isn't it?


I think Axon was talking about the LSB in a multi-bit system, which is not the same as a 'massively oversampled 1-bit signal' - it's not oversampled on the disc... Also the sigma/delta converter you're boldfacing is a dac: it's a decoder, so it can do nothing about your encoding...

Maybe I just don't get the joke?