Your guy doesn't know what he is talking about. A typical CD-player does not reread and they do have a buffer, it is the heart of the system.
Try playing a CD-rom in your CD-player and you will see that in most players it will play only the output will be muted.
A CD doesn't have bits, it has pits.
Here is a good place to start:
CD BOOK
Try playing a CD-rom in your CD-player and you will see that in most players it will play only the output will be muted.
A CD doesn't have bits, it has pits.
Here is a good place to start:
CD BOOK
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A mysterious appeal to authority. I like it. 😀
Well maybe I don't know much about CD players, but what is typical?
I remember a very cool demo by a Sony rep back in the late 80s. It was a Sony Discman that had a buffer to prevent skips caused by bumps. He could open the lid, pop out the CD (quickly!) and then put it back in. Never stopped playing. Talk about a Wow! demo. That's how I learned about buffers in CD players.
But maybe they don't put them in CD players now. Memory prices being so high and all.
I want to emphasize just how awesome it is that James is going forward with this test. Hopefully SY's protocol is solid, as this is a great learning opportunity.
The rest of the ******* back and forth (whether I'm guilty or no) is a wild sideshow to this fact.
Considering the business he worked with, I imagine it includes all CD players, not just audiophile stuff. Walkman, car, boom box, etc.
If they all have a buffer, it's a shitty one given how easily a bump can make an audible skip.
But I do have a memory of something with a buffer that you couldn't get to skip, and they advertised it. Maybe it was Walkman.
What is a "typical" CD player now anyway? My stand alone CD player is well over 10 years old... Can't recall when I last used it. Last time I played a CD "live" it was in a laptop - definitely a buffered device. Our kids don't own a CD player - they buy CDs but rip them to listen to.
All CD players need a buffer in order to do things like de-interleaving. CD players do not do re-reads. Generally they do not interpolate missing bits; they use interpolation as a last resort when error correction fails due to too many bit errors in the raw data stream. The last sentence is true: if the scratch etc. is large enough then you will hear it as the player will mute. The rest is roughly the opposite of the truth, so you need to select your experts more carefully. Given that he has so poor an understanding of what happens, it is not surprising that your expert believes that a good transport is necessary.Destroyer OS. said:
I dunno DF96, should I believe you're an expert on everything ever? Buffer may be up to some interpretation. We know that in many transports it's not merely longer than a fraction of a second, do we call it a buffered unit? I wouldn't, but it may exist to make the system operable.
Further I've heard plenty of CD's with scratches do "re-reads" where you hear it play the same thing over and over because it can't track past that point. So I'm not really inclined to believe different. We're talking about audio players, not computer drives.
The only thing interesting in that book that I can view was this.... And it claims to be a textbook.
Further I've heard plenty of CD's with scratches do "re-reads" where you hear it play the same thing over and over because it can't track past that point. So I'm not really inclined to believe different. We're talking about audio players, not computer drives.
The only thing interesting in that book that I can view was this.... And it claims to be a textbook.
You pasted text talks about CD players, not the transport section used with an external DAC. So what are they listening to?
Here's a little further reading for you. BTW, all the CDP schematics I've looked at had ram chips. Some of that is for other things, but to state that typical players don't buffer is a strange thing to say.
https://hydrogenaud.io/index.php/topic,11909.msg121422.html#msg121422
Here's a little further reading for you. BTW, all the CDP schematics I've looked at had ram chips. Some of that is for other things, but to state that typical players don't buffer is a strange thing to say.
https://hydrogenaud.io/index.php/topic,11909.msg121422.html#msg121422
I don't claim to be an expert. You don't need to be an expert to know that your 'expert' is wrong. A buffer is a buffer - you can't do de-interleaving on the fly. You can, sometimes, do error correction on the fly. I make no comment about the size of the buffer, but it certainly has to be big enough for de-interleaving.Destroyer OS. said:
OK, to clarify: A CD player may do a re-read, but only when it has totally lost the track and so has to try to get itself straight again. By this time the sound will have already muted, and it will be obvious that the drive or the media need some attention.
I don't know which book this is an excerpt from, but I can tell you that the writing style is quite unlike any textbook I have ever read on any subject. I will leave the philosophers on here to argue about whether a claim by a book to be a textbook is sufficient to make the book a textbook.
Also worth noting that even a cheap transport will handle a 1.5mm gap/scratch without skipping or losing its way.
Use my handle here at syclotron dot com.
And yes, I am always explicit and public with methods and results. I just care about data, not which way it goes.
I think that that the guy who wrote the 'textbook' is someone with some experience with listening to different CD systems. He does it RIGHT! He only compares 2 units and takes his time. I know that it takes me 'hours' to be sure of what I hear in audio playback electronics, as well.
Does anybody here actually have any experience with LISTENING to different transports? If not, how can you form an opinion about possible transport sonic differences? Too many opinions, usually negative, and not enough expert design or experience with CD transports.
Does anybody here actually have any experience with LISTENING to different transports? If not, how can you form an opinion about possible transport sonic differences? Too many opinions, usually negative, and not enough expert design or experience with CD transports.
Does anyone here actually have any experience with MEASURING voltage drop around circuit loops? If not, how can you form an opinion about possible violations of the conservative (i.e. curl-less) quasi-static electric field? Too many opinions, usually conventional, and not enough expert design or experience with alternative versions of electromagnetism.
Yes John, I lot of us have experience listening to CD players and CD transports. And yes, the advice given about listening is good, except that knowing which is which can skew your preferences.
But that's really more about listening to the DAC, and more specifically, its analog section. There can be real differences there that have nothing to do with the how the bits are retrieved from the disc - which is what the "transport" part is all about.
But that's really more about listening to the DAC, and more specifically, its analog section. There can be real differences there that have nothing to do with the how the bits are retrieved from the disc - which is what the "transport" part is all about.
https://en.wikipedia.org/wiki/Electronic_skip_protection
Because it was used in portable, primarily. At least the longer buffers where that mattered.
If you are regularly getting buffer underruns on your regular cdp, I suggest looking at the media itself or the state of repair of your cdp. Something is amiss.
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