Ping: John Curl. CDT/CDP transports

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James A

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Joined 2006
#1
Hi John,

EDITED:

Would you please explain why not all stand alone CDT/CDP transports sound the same.

As a designer of audio equipment, I would like to hear the reasons why in your own words.

I assume it starts with the power supply.

Thanks,
Jim
 
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#4
Sorry guys,

I mean John Curl the designer.


jan.didden said:
Also I think he believes that all CDP CD players sound the same with SPDIF although his post is not very clear on that.


No, that is not what I think at all. From my personal listening experiences all CDT/CDP transports do not sound the same.

I guess I did a lousy job of asking my question in my posted message.

I am hoping John will give his reasons why as a designer of audio equipment why all CD transports do not sound all the same.
 
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#6
jan.didden said:
But that is your personal opinion. Other people can have other personal opinions. I don´t see the connection between a personal opinion and an audio designer.

But maybe John will chime in.

Jan
Click to expand...

jan.didden,

In your opinion, better yet listening experience, do all CD transports sound the same?

As for my opinion it doesn't carry much weight. What does is all the other opinions out there that say they hear differences in CD transports as well.

It's the naysayers that say all CD transports sound the same. Actually they start out by telling you digital doesn't have a sound. NO kidding?
The naysayer then goes on and on about 1s and 0s, bits are bits, and bit perfect. They say measurements between CD transports are the same. They can't sound different. But that's not what my ears tell me.
 
#7
Why is bits not bits? I send for instance hundreds of pages of text through the internet and at the other side they come out exactly the same, not one letter changed. And that while the total file has been cut up, parts send via different routes, and finally assembled. All 100% perfect.

A CD player has so much error correction and redundancy on the disk that even with damaged CDs, the bit stream coming off the player is 100% perfect in almost all cases. Once in a blue moon there is an unrecoverable error but if that happens there is no mistaken - it is a clearly audible short event.

So the upshot is that yes, bits is bits.

Now the other side (the end actually) is of course the DAC. In the DAC there's some form of reclocking to get rid of eventual jitter and the reconstruction filter to produce the audio. These are parts of the system that can sound different and many do.

But as far as the digital bitstream is concerned, running through your digital cabling, that's perfect for all intends and purposes.
Just as confident I am that the text of this post that I am typing will exactly be the same as the text that will appear on your screen. Even via WiFi 😉

Jan
 
#9
jan.didden said:
Why is bits not bits? I send for instance hundreds of pages of text through the internet and at the other side they come out exactly the same, not one letter changed. And that while the total file has been cut up, parts send via different routes, and finally assembled. All 100% perfect.

A CD player has so much error correction and redundancy on the disk that even with damaged CDs, the bit stream coming off the player is 100% perfect in almost all cases. Once in a blue moon there is an unrecoverable error but if that happens there is no mistaken - it is a clearly audible short event.

So the upshot is that yes, bits is bits.

Now the other side (the end actually) is of course the DAC. In the DAC there's some form of reclocking to get rid of eventual jitter and the reconstruction filter to produce the audio. These are parts of the system that can sound different and many do.

But as far as the digital bitstream is concerned, running through your digital cabling, that's perfect for all intends and purposes.
Just as confident I am that the text of this post that I am typing will exactly be the same as the text that will appear on your screen. Even via WiFi 😉

Jan
Click to expand...



Then please explain this.

http://www.diyaudio.com/forums/digi...affordable-cd-transport-shigaclone-story.html



//
 
#15
James A, I don't know what to tell you, but I agree with you that most audio components sound different, if you are open to hear the differences. Unfortunately, digital is not where I normally design, but power supply peak current delivery and filtering from getting and contributing to line garbage can be two important factors in CD's, etc.
 
#16
john curl said:
James A, I don't know what to tell you, but I agree with you that most audio components sound different, if you are open to hear the differences. Unfortunately, digital is not where I normally design, but power supply peak current delivery and filtering from getting and contributing to line garbage can be two important factors in CD's, etc.
Click to expand...

John,
Thank you for the reply.


Best regards,
Jim
 
#17
SY said:
Please explain this, which has the same quality of evidence.
Click to expand...

Sy, I'd like to take you on a jet-boat river tour or something fun, before you have a stroke... good lord.

I can only imagine the type of hazing you would've been into if you were in charge of a fraternity.

As far as CD players go, noise on the output can be an issue down the line. And also I don't think typing online is a good comparison to streaming. Not unless you type 16-bits at 44khz streaming to a chat room. CD players can play burned CD's that have bad ink that smears and will confuse a computer trying to rip them, and yet they often play fine; or so it seems. The lasers ability to read it will have to do with accuracy, which is often a different angle than used in computer drives I believe.

Also, maybe mistakenly so, I thought CD player's buffers had more to do with being able to circumnavigate errors to not interrupt playback? It allows a re-read so that it doesn't entirely lose it's place.
 
#20
Let me waddle in here.

James A, you missed the point SY was trying to make. You keep listing web pages as evidence, but they are all devoid of evidence. None of them meet any standard of scientific rigour. Anybody could literally just sit down and write those off the top of their heads. Credentials aren't proof, and what are impressive credentials in audio? Jan's?

Ask JC for advice on CD transports? After his shameless support of Bybee devices, I wouldn't ask him for directions, let alone recommendations on anything audio.

BUT I think SY and Pano are too glib on the subject. I doubt they use CDP's regularly and so miss some obvious points. I use DVDP's all the time; I wear them out. All the consumer devices show signs of wear and having difficulty playing DVD's or CD's over time. I suspect (because I have no proof, hint) all of the currently constructed consumer grade transports are incapable of producing bit-perfect streams because of design compromise. I can't speak for higher end stuff because I never buy any. I think all is not so simple.
 
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