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  • keLston
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Are CDs lossless?
Alright, from my thread on whether or not WAV files are lossless, for all intents and purposes, with regards to ripping direct from a CD, it seems like, yes, WAV is lossless.

So going back up the chain from a lossless audio format, so far all data is exact, from lossless audio file <-> wav.

Given that... are CDs lossless? In recording a CD, there has to be a conversion from analog to digital. At the same time, a human voice and instruments, I believe, are not limited to samples per second. So in theory, unless I am wrong (which I will admit that I definately could be), to have a lossless audio CD, the result would have to be an infinite bit rate and an infinite sample rate.

This would mean because CDs are at 16/44.1k (I think?), there is quite a bit of data that is lost. Unless you define lossy, as compression.

So... is a CD lossy?

And if not, how far up the chain do you have to go to get to the point of loss, if there is loss at any point at all? (Chain = Lossless audio format -> Artist)

Are CDs lossless?
Reply #1
::sigh::

and so a can of worms is opened...

if you are asking whether an increase in the sampling rate or bitrate, for example that employed by a SACD, will result in less loss (better quality), the answer is no, from what i have read on this forum. it will not result in better quality. its like frame-rates in video games: once you're over about 60 frames per second, any more is a waste.

have i actually learned anything from reading this forum? or is this just a bunch of BS?
i hate cats

  • sthayashi
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Are CDs lossless?
Reply #2
The artist himself is lossy.

Why do you think a particular recording may require multiple takes?

  • amano
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Are CDs lossless?
Reply #3
answer 1) every A/D and D/A conversion is "lossy". the better the converter the better the sound.

answer 2) a loss is only important if someone can hear the loss. as far I know, 16 bit should be sufficient to be transparent.

  • lexor
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Are CDs lossless?
Reply #4
can I expand the original question, please? thanx

what format is original audio for Movies stored in? In the booklet for T2:Extended Edition (2003) it says that when sound is converted to DVD format the audio is reduced in size by 98%. somehow I don't think original was wav
The Plan Within Plans

Are CDs lossless?
Reply #5
The data on Audio CDs is not compressed, so the terms "lossy" and "lossless" do not apply.

  • Xenion
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Are CDs lossless?
Reply #6
i wouldn't call it loss. cds are just made in a certain standard. i don't think that you can call this a quality loss because the only thing that has no quality loss is when you're listening to an instrument live and unplugged. this has infinite resolution.
  • Last Edit: 31 July, 2003, 05:11:18 PM by Xenion

  • rjamorim
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Are CDs lossless?
Reply #7
What a worthy and useful thread. >_<
Get up-to-date binaries of Lame, AAC, Vorbis and much more at RareWares:
http://www.rarewares.org

Are CDs lossless?
Reply #8
1: Lossy / lossless refers to compression, and thus has nothing to do with CDs
2: Many modern recordings are completely digital, from the microphone to the CD.  Therefore analog to digital is irrelevant.
3: No.  You cannot hear the sound "degredation" on a CD.  Hell, most people can't even seem to tell the difference between 128 bit MP3 and CD.  But CDs contain more data than the air can even carry.  There is no loss, at least not a loss perceptible to humans, or detectible on modern audio equipment.

Are CDs lossless?
Reply #9
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can I expand the original question, please? thanx

what format is original audio for Movies stored in? In the booklet for T2:Extended Edition (2003) it says that when sound is converted to DVD format the audio is reduced in size by 98%. somehow I don't think original was wav

The "original" digital medium for audio is always PCM.

  • sthayashi
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Are CDs lossless?
Reply #10
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2: Many modern recordings are completely digital, from the microphone to the CD.  Therefore analog to digital is irrelevant.

This part is not necessarily accurate.  Nearly all sounds we hear are not electric (even 'electric guitars').  In order to capture that sound digitally, it has to be sampled (which is the fundamental concept of digitization).  True lossless would have a sampling rate 2 times higher than the highest harmonics created by a sound.

Even then, don't forget that air is one of the ULTIMATE lossy compressors.  So if we're being excessively pedantic here, there is loss between the sound source and the transducer of the microphone.

The point is that if you want to be absolutely technical about things, there is loss well before it makes it to the final media.  Do you ever hear this?  Again, technically yes, depending on your reference.  One statement I've always wanted to make with ABXing is that no setup (or VERY few) can pass an ABX from a live performance.  (Not that it's really been attempted).

Also, this was more to try and draw some parameters from the original question, how far back in the recording/processing mix before you get to lossless (essentially).

  • Jebus
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Are CDs lossless?
Reply #11
I don't even know where to start

Without getting all cranky, I would suggest you go out and do some reading before starting any more "profound" threads like this one.

Any recording is lossy of course, since it does not record everything happening in the room at the time of the original performance. Audio is lossy because you loose the smell and feel of the room. Stereo is lossy because it puts all the subtle acoustic directivity information into only one of two channels. The digital recording or mastering process is lossy because, at a basic level, it ultimately has to quantize things into 1s and 0s. Lots of other little losses of course also come into play.

Obviously (well, at least to me) we are not concerned with that on this page. We are concerned with "psychoacoustic audio compression". Please for godsakes read up on some audio basics.

  • sthayashi
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Are CDs lossless?
Reply #12
Jebus, you are just a hair too slow

  • AtaqueEG
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Are CDs lossless?
Reply #13
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Alright, from my thread on whether or not WAV files are lossless, for all intents and purposes, with regards to ripping direct from a CD, it seems like, yes, WAV is lossless... are CDs lossless?
So... is a CD lossy?

Is there any actual point to this, Mr. ? Or are you trying to out-l33t somebody? This is like asking what is the sound of one hand clapping (ABX'ed, please) or how many angels fit on a pin's head.

I mean, anybody who was made some research knows that NO format, maybe ever, will be Lossless in relation to the originally produced sound (the artist performance, that is).

Either deal with it or don't. Just don't try to play smart here.

(I am really making an effort here...counting: 1,2,3,4,5...) 
I'm the one in the picture, sitting on a giant cabbage in Mexico, circa 1978.
Reseñas de Rock en Español: www.estadogeneral.com

Are CDs lossless?
Reply #14
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2: Many modern recordings are completely digital, from the microphone to the CD.  Therefore analog to digital is irrelevant.

This part is not necessarily accurate.  Nearly all sounds we hear are not electric (even 'electric guitars').  In order to capture that sound digitally, it has to be sampled (which is the fundamental concept of digitization).  True lossless would have a sampling rate 2 times higher than the highest harmonics created by a sound.

Even then, don't forget that air is one of the ULTIMATE lossy compressors.  So if we're being excessively pedantic here, there is loss between the sound source and the transducer of the microphone.

The point is that if you want to be absolutely technical about things, there is loss well before it makes it to the final media.  Do you ever hear this?  Again, technically yes, depending on your reference.  One statement I've always wanted to make with ABXing is that no setup (or VERY few) can pass an ABX from a live performance.  (Not that it's really been attempted).

Also, this was more to try and draw some parameters from the original question, how far back in the recording/processing mix before you get to lossless (essentially).

You quoted me, but I don't really think you read what you quoted:  ... completely digital, from the microphone to the CD ...

I wasn't talking about the air.  I was talking about the equipment.  (Though if you'd bothered to read the next line, I did mentioned the air later.)  If you want to be overly anal, then yes, I suppose it undergoes an analog->digital conversion going into the microphone.  But professional microphones will sample at rates far higher than the human ear needs.  So that's completely moot.

And if you're going to be so pedantic, you should note that electric is not the same as digital.  Electric guitars do produce an electric signal, simply not a digital signal.

And ABXing from a live performance?  Ugh.  The point of a recording studio is to produce an output which exceeds live performance.  That doesn't mean that the equipment can't record data well enough to fully capture a live performance.  It just means that such an effort is useless.

I'd bet that well over 99% of the data loss associated with recording comes from the mastering process (read: intentional loss), rather than from equipment limitations.

P.S. Data loss that the human ear cannot detect is completely irrelevant as far as I'm concerned.  I don't give a damn if they lose frequencies only dogs can hear, nor do I care if they can't capture (on CD) noise above the threshhold of pain.  Such effort is a waste.
  • Last Edit: 31 July, 2003, 06:50:11 PM by Curi0us_George

  • sthayashi
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Are CDs lossless?
Reply #15
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You quoted me, but I don't really think you read what you quoted:  ... completely digital, from the microphone to the CD ...

I wasn't talking about the air.  I was talking about the equipment.  (Though if you'd bothered to read the next line, I did mentioned the air later.)  If you want to be overly anal, then yes, I suppose it undergoes an analog->digital conversion going into the microphone.  But professional microphones will sample at rates far higher than the human ear needs.  So that's completely moot.

And if you're going to be so pedantic, you should note that electric is not the same as digital.  Electric guitars do produce an electric signal, simply not a digital signal.

I'd bet that well over 99% of the data loss associated with recording comes from the mastering process (read: intentional loss), rather than from equipment limitations.

P.S. Data loss that the human ear cannot detect is completely irrelevant as far as I'm concerned.  I don't give a damn if they lose frequencies only dogs can hear, nor do I care if they can't capture (on CD) noise above the threshhold of pain.  Such effort is a waste.

First, I should tell you that my argument was not directed at you, but at the original poster.  Your second point seemed like the best place for me to squeeze in.

As for your quote, I read it, do you understand it?  Microphones have an analog component in them, a transducer*.  Hence the reason I make mention that sound is not electric.  If it were, then we wouldn't have to worry about the loss due to the transducer, now would we?  In either case, there is an analog to digital conversion that must take place, hence the loss there.  Also, if microphones sample far higher than the human ear needs, then there must be resampling that occurs since 44.1kHz is barely above what it needs to be.

* I'm not aware of any purely digital transducers in microphones.  If there are, then I'm potentially wrong about it being analog.  However, turning audio energy into electrical energy is ALWAYS lossy.

As for your 3rd point, which I felt had no bearing to my post, you mention that CD contains more data than air can carry.  I felt that this was an error at best and a blatently misleading statement at wost.  Air can carry 23kHz tones just fine, whereas CDs can't.  Granted it's above the threashold of human hearing, but you didn't mention that until your response.

Finally, although I agree with you on your statement that most audio loss will occur in the mastering process, I'm not certain that it's not in part due to equipment limitations.  Otherwise, there would be absolutely no reason for 24-bit 96kHz recordings.

Now before you flame me, be sure at this point to reread my first 2 sentences

  • amano
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Are CDs lossless?
Reply #16
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Otherwise, there would be absolutely no reason for 24-bit 96kHz recordings.

there are people who say that it's not necessary at all.

  • ScorLibran
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Are CDs lossless?
Reply #17
The moment audio is *sampled*, it becomes lossy.  Even if a sound it sampled at 1,000,000,000,000,000,000,000 kHz, it is still not infinite, the way our ears hear live audio.

Anyway, I think this thread is more lossy than CD audio will ever be.

I have a headache...I'm gonna go find some aspirin now...

  • KikeG
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Are CDs lossless?
Reply #18
Some things...

Good microphones are just analog, there's no conversion to digital inside. The conversion is performed at a ADC outside the microphone.

Being picky, one could say that the fist lossy stage happens when the mic captures the sound. Here you go from a 3d soundfield to a mono-signal from a single microphone. But this happens more because of the usual micing technique. On a binaural recording this wouldn't happen, since you record exactly what goes to the ears.

On the other side, a microphone can't capture sound with infinite precision, so one could say that microphones are lossy, so the first loss always happens at the mic. However, I believe good mics can capture sound with greater accuracy than the ear has, so this should be no problem in practice. So, in a binaural recording with  good mics, one could say that there would no audible loss at all at the mic recording stage, since you record exactly what goes to the ears, with a greater accuracy than the ear has.

In practice, many mics are not transparent, in the sense that they alter in an audible way the sound, but this is intended, because it gives a type of sound that the person making the recording wants. And binaural recordings don't give either the kind of sound the people making recordings want, so to talk about true "transparency" and "lossless" recordings doesn't have much sense even if there were perfect recording mediums.

Now, an AD/DA conversion is no more lossy than recording the signal on tape, for example. In fact it is quite less lossy. This is because an AD/DA conversion does nothing to the signal but adding some minuscule background noise and a cutoff of frequencies over near half the sampling rate. But nothing else, both in theory and using a good ADC/DAC. Dither and the reconstruction filters take care of all the "intuitive" problems of digital recording and playback.

And, in my opinion, 24/96 recordings are not neccessary at all. 24/44.1 is enough for recording and editing, but 16/44.1 is enough for playback a properly mastered signal. This is because the noise added and the frequency cutoff at a proper DA stage of a 16/44.1 sampled signal, is beyond what the ear can notice.

Edit: some few additions about the lossy nature of mics.
  • Last Edit: 01 August, 2003, 02:26:55 AM by KikeG

  • 2Bdecided
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Are CDs lossless?
Reply #19
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The moment audio is *sampled*, it becomes lossy.  Even if a sound it sampled at 1,000,000,000,000,000,000,000 kHz, it is still not infinite, the way our ears hear live audio.

The neural signal from your ear to your brain is digital. It's quantised (1 or 0), but not sampled (the pulse can happen at any point in time). The transduction process from pressure wave in air to neural signal is very lossy. The neural signal itself is very very noisy, but our brain processes it well.

Microphones and loudspeakers are significantly less "ideal" than any other component in the audio reproduction chain. That's not to say that your ear can't hear a lesser imperfection due to bad sampling through the greater imperfection due to a poor loudspeaker. It's just to say that the design (and placement!) of microphones makes a greater contribution to the sound that the design of the A>D and D>A convertors.

Are CDs good enough? We've been here before - see the FAQ:
http://www.hydrogenaudio.org/forums/index....7516#entry74075

Cheers,
David.

  • ScorLibran
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Are CDs lossless?
Reply #20
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The moment audio is *sampled*, it becomes lossy.  Even if a sound it sampled at 1,000,000,000,000,000,000,000 kHz, it is still not infinite, the way our ears hear live audio.

The neural signal from your ear to your brain is digital. It's quantised (1 or 0), but not sampled (the pulse can happen at any point in time). The transduction process from pressure wave in air to neural signal is very lossy. The neural signal itself is very very noisy, but our brain processes it well.

That's a good point.  My argument should really be that after the processing our brains do, although we don't really interpret every bit of the sound, it is still impossible for *any* digital recorded format to perfectly match every bit of what we would hear live.

In other words, to sound "perfect" to a person's ears, a recording would have to only lose those bits which that persons brain would lose/discard during mental processing anyway.  Two main problems with that...(1) Different people will hear differently, since they have different brains doing the processing, and (2) Even the same person would hear the sound a little differently at each listening session as the brain doesn't process anything the exact same way twice in a row.

Even if these issues are completely non-perceptible 99.99999% of the time, I contend that the word "lossless" is a big, serious word that only means one thing.  It's the same concept as being pregnant...you are or you're not, no in-betweens.  Once a single bit of data is lost, then you have a lossy recording, whether or not any brain in the world could have ever interpreted that lost bit.  So, since technically *any* digital recording of any kind that was ever made is lossy compared to live, the next consideration is transparency, which is subjective to each person who listens to a piece of audio (and on a side note, and as everyone here knows, also happens to be the very center of interest in psychoacoustic audio compression).

Keep in mind that my argument is that a digital recording cannot technically be lossless (as I said before, because of sampling).  But calling, for example, FLAC lossless means soemthing else, because you're not comparing it with the original audio source (i.e., live performance), but rather with the original uncompressed (already recorded) audio file it came from.

Is CD audio lossless?  It can't be...ever...not technically.  Without some miraculous new recording technique, in my opinion, *no* digital recording format could ever be lossless.  Even if you set up a million of the world's best quality microphones plugged into the world's best quality digital recording equipment around one guy playing an acoustic guitar.  One ever-so-insignificant bit of sound is lost between sample #954 and sample #955. It's now a lossy recording.  Maybe not as lossy as a 64kbps MP3, but the term "lossless" could technically never be correctly used to describe it, nonetheless.

A better question, I think, would be "Is CD audio transparent?".  Or even better: "Is CD audio good enough?"  My answer?  I've got not a single complaint...


Edit:  Re-reading my post, I realize how extremist my point-of-view sounds.  Oh well...I'm a typical Scorpio...black-and-white, no middle ground, ever...it's perfect or it's flawed...period. 
  • Last Edit: 01 August, 2003, 06:00:14 AM by ScorLibran

Are CDs lossless?
Reply #21
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First, I should tell you that my argument was not directed at you, but at the original poster.  Your second point seemed like the best place for me to squeeze in.

If my post sounded rude, I should apologize.  I thought you were arguing with me, and I can be overly argumentative at times. 

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As for your quote, I read it, do you understand it?  Microphones have an analog component in them, a transducer*.  Hence the reason I make mention that sound is not electric.  If it were, then we wouldn't have to worry about the loss due to the transducer, now would we?  In either case, there is an analog to digital conversion that must take place, hence the loss there.  Also, if microphones sample far higher than the human ear needs, then there must be resampling that occurs since 44.1kHz is barely above what it needs to be.

* I'm not aware of any purely digital transducers in microphones.  If there are, then I'm potentially wrong about it being analog.  However, turning audio energy into electrical energy is ALWAYS lossy.

I suppose this is technically correct.  So I'll just yield the point.  There is always some analog -> digital conversion.  But again, if the rate is high enough to capture all a human can hear, it's not lossy, at least not from a practical standpoint.  And yes, there is resampling going on.  There always is.  I'm pretty sure that most mastering is done at above 44.1, so it has to be downsampled before it hits the CD.

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As for your 3rd point, which I felt had no bearing to my post, you mention that CD contains more data than air can carry.  I felt that this was an error at best and a blatently misleading statement at wost.  Air can carry 23kHz tones just fine, whereas CDs can't.  Granted it's above the threashold of human hearing, but you didn't mention that until your response.

Well, I did say "Data loss that the human ear cannot detect is completely irrelevant as far as I'm concerned."    The only thing CDs are really missing is the ability to carry tones at volumes loud enough to cause physical pain.  And honestly, I'm not so concerned about that. 

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Finally, although I agree with you on your statement that most audio loss will occur in the mastering process, I'm not certain that it's not in part due to equipment limitations.  Otherwise, there would be absolutely no reason for 24-bit 96kHz recordings.

I firmly believe that most data is lost as a result of compression.  That's an intentional process.

Are CDs lossless?
Reply #22
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Good microphones are just analog, there's no conversion to digital inside. The conversion is performed at a ADC outside the microphone.

Actually, there are microphones which perform the digital conversino internally, but I withdraw my previous statement that they are in common use.  I was apparently wrong.

  • 2Bdecided
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Are CDs lossless?
Reply #23
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Is CD audio lossless? It can't be...ever...not technically. Without some miraculous new recording technique, in my opinion, *no* digital recording format could ever be lossless. Even if you set up a million of the world's best quality microphones plugged into the world's best quality digital recording equipment around one guy playing an acoustic guitar. One ever-so-insignificant bit of sound is lost between sample #954 and sample #955.



But the loss (perceived or imperceptible) isn't between sample points - your suggestion that digital audio is lossy because of this is wrong, if I'm understanding you correctly (which maybe I'm not!).

Any recording of the electrical signal which comes from a microphone, whether that recording is analogue or digital, is lossy. However, you can put bounds on what you lose in a digital system. Sample two million times per second, and all frequencies up to one million cycles per second (i.e. 1MHz) will be stored - since the ear can only hear up to 20kHz, that's overkill - certainly lossless as far as human hearing goes!

Then, the bit depth defines the noise floor. 16 bits doesn't match human perception (though it's more than enough for most recordings) - 24 bits is more than enough, though we can't even design convertors of this accuracy, partly because of basic electronics and physics, but also because the 24th bit is quieter than the sound of silence ;-).

There are endless discussion on the limits of digital in the threads in the FAQ - take a look if you doubt either of the above.


The reason recording is lossy is because it doesn't create the exact same sound pressure variations throughout this listening space. The spatial information just isn't there. Stereo isn't bad, 5.1 isn't much better - neither take you to a "you are there" or "they are here" listening experience, though it's possible to get close to either.

There are techniques like Wave Field Synthesis (warning: link to pdf file) and Ambisonics (or even Ambiophonics if you don't mind having your head clamped in place!) that aim to, and (in some cases) even can re-create the audio signal at your ears exactly in theory - all that remains is the distortion introduces by the microphones and speakers.


But all this idea of sound reproduction perfection is so far away from the reality of most modern recordings that it's almost laughable. And, what's more, given a perfect sound reproduction system, our brains won't be happy: there's nothing to look at! So, the best recordings are just a little bit "better" than life. Not too much better - a great record producter once described it as "like putting a little bit of rouge on the cheeks of a beautiful woman" - you take perfect and make it more perfect! Most modern recordings slap bright red paint on the cheeks and blue paint in each eye!

Cheers,
David.

EDIT: added the quote because the discussion had moved on between hitting reply and hitting post!
  • Last Edit: 01 August, 2003, 06:28:20 AM by 2Bdecided

  • Madrigal
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Are CDs lossless?
Reply #24
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So in theory, unless I am wrong (which I will admit that I definately could be), to have a lossless audio CD, the result would have to be an infinite bit rate and an infinite sample rate.

So... is a CD lossy?

I believe you are right. And that CD's are therefore lossy. Please let us know when you have achieved sufficient deity to offer hardware and/or software remedies for this serious situation.

Regards,
Madrigal