Forum Home Forum Home > Other music related lounges > Tech Talk
  New Posts New Posts RSS Feed - Digital Audio Myths - Listening on a PC
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Topic ClosedDigital Audio Myths - Listening on a PC

 Post Reply Post Reply Page  <1 45678 19>
Author
Message
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 05 2005 at 13:51
No, things are not that simple
Have you heard about “Jitter” phenomenon?
Here are some text extracts i found on the net:

About VRDS system:

“TEAC manufactures what is felt by many to be the finest CD transport mechanism available. Their massive VRDS drive uses a proprietary clamping system that corrects for disc warp while reducing jitter-inducing vibration. The incredibly tight manufacturing tolerances of the mechanism are said to be an order of magnitude beyond any drive used for audio applications.”

About spectral drive, using modified Teac VRDS mechanic:

« The vital role a transport plays cannot be overstated. All subsequent signal processing and amplification quality will be determined by the ultimate ability of the transport to recover the correct data from the disc, and deliver it without errors in timing. This is a major engineering challenge. Until now, data losses and introduction of timing errors (jitter) have plagued virtually all digital playback systems. The Spectral SDR-3000 Reference Transport is a quantum step forward in precision and quality, virtually eliminating jitter and resolution losses.

A REFERENCE CD DRIVE
One conspicuous area of compromise among high-end audio CD transports is the choice of the compact disc drive itself. Most high-end transports rely on standard CD drives developed for mass-market automobile and CD ROM applications. Although inexpensive, these drives were never designed for the performance and durability requirements of truly high-end audio. Plastic construction and optics are an undeniable compromise in today's finest compact disc components.
Spectral engineers evaluated many premium drives and found virtually all to be compromised by the imperatives of mid-fi cost constraints. A cooperative effort between TEAC and Spectral has resulted in a custom version of their finest hand built Esoteric drive, made exclusively for the SDR-3000.
Unlike most available CD drives, the Spectral/Esoteric drive is developed exclusively for high-end audio applications. Based on the low production Esoteric P2s drive, the Spectral/Esoteric reflects a marriage of state-of-the-art mechanical and opto-electrical performance. Vibration-Free Rigid Disc Clamping (VRDS) allows the convenience of front disc loading without the attendant performance compromise. (Most other front loading drives use magnetic disc clamping, and the magnetic puck seldom centers itself exactly, inducing mechanical vibration). The VRDS clamping system offers full vibration damping of the sensitive compact disc while eliminating the inconvenience of additional disc weights and stabilizers commonly required with top-loading transports.
The VRDS system is a new generation design built to exacting standards for Spectral. No other drive that we have evaluated offers the data precision and mechanical quality achieved here. Superiority of the Spectral/Esoteric drive starts with its full size die-cast zinc/bronze disc turntable and stabilizer clamp which keeps disc and laser pickup in their precise relative positions. Servo correction need only deal with tracking the variable disc rotation speed because of the superb inertial damping and stability of the turntable which employs a double-layer construction of machined brass and aluminum. The overhead turntable's heavy design and high precision clamp greatly reduce undesirable vibration while its massive bearing and 6 mm spindle ensure excellent rotational stability and long life.
The superstructure of the drive is cast from non-resonant zinc-alloy including a massive 1 Kg base unit and vibration resistant bridge assembly for the precision motor and bearing of the disc turntable. A floating suspension system with sophisticated resonance damping completes the state-of-the-art mechanicals.
The disc loading system also sets high standards for precision and durability. Its non-resonant loader tray rides on twin polished stainless steel linear bearing rods for positive disc control and long life. This polished bearing loading mechanism is distinctly superior to the weak plastic bearings found in conventional CD drives.
BALANCED CHASSIS DESIGN
Massive construction alone does not address the multiple dimensions of resonance and vibration management required in a digital transport. The enclosure design of the SDR-3000 is an essential element of distortion control, and, as a result, signal integrity.
Multiple shield construction compartmentalizes sensitive transport sections and limits noise coupling. Mechanical and harmonic disturbance is eliminated through a critical series of laminated sections and damping elements. Radius corner, welded aluminum chassis design detunes resonant frequencies which can impact clocking and program signals. The essential requirements for chassis rigidity and optimum vibration control are carefully balanced in the SDR-3000.”


You can also have a look at this page:

http://www.teac.com/esoteric/NewEsoteric/UX-1.html
Back to Top
MikeEnRegalia View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: April 22 2005
Location: Sweden
Status: Offline
Points: 21149
Direct Link To This Post Posted: September 05 2005 at 13:52

Originally posted by oliverstoned oliverstoned wrote:

OK, but you just forget the data correction issue.

Music is made of MANY 0 and 1, and the human ear, or brain is very sensitive (more than eyes for example) and missing or approximative infos can be hear clearly. That's the case with a drive suffering from vibes.It brings reading error that can be "perfectly" corrected.
A CD with minor scratches will be read "perfectly" in the way that there will be no gap in the music(as long as the scratches are not too deep),but the sounds get harsher as the corrections circuits are working more .
In the case of the software, it makes virtually no difference, but in the case of music played on a transparent system, it's obvious.
On another hand, if the scratch is too deep and too much info missing, the cd will "jump" and the software will "bug"!

That's the most ridiculous statement that I've read so far. Please, you're making a fool of yourself. You don't have to believe me ... don't you know any software developers or other computer specialists you can ask about this? Change one bit in your typical software and depending on where the mistake is located, your software may run flawlessly (if you don't use any function that uses the faulty part) or just crash. And if you have bad luck, it might just erase your hard disk ...

 

Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 05 2005 at 13:53
Yes, but software don't suffer from "jitter" problems.
Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 05 2005 at 13:59
"Subject: [2-15] What are "jitter" and "jitter correction"?
(1998/04/06)

The first thing to know is that there are two kinds of jitter that relate to audio CDs. The usual meaning of "jitter" refers to a time-base error when digital samples are converted back to an analog signal; see the jitter article on http://www.digido.com/ for an explanation. The other form of "jitter" is used in the context of digital audio extraction from CDs. This kind of "jitter" causes extracted audio samples to be doubled-up or skipped entirely. (Some people will correctly point out that the latter usage is an abuse of the term "jitter", but we seem to be stuck with it.)

"Jitter correction", in both senses of the word, is the process of compensating for jitter and restoring the audio to its intended form. This section is concerned with the (incorrect use of) "jitter" in the context of digital audio extraction.

The problem occurs because the Philips CD specification doesn't require block-accurate addressing. While the audio data is being fed into a buffer (a FIFO whose high- and low-water marks control the spindle speed), the address information for audio blocks is pulled out of the subcode channel and fed into a different part of the controller. Because the data and address information are disconnected, the CD player is unable to identify the exact start of each block. The inaccuracy is small, but if the system doing the extraction has to stop, write data to disk, and then go back to where it left off, it won't be able to seek to the exact same position. As a result, the extraction process will restart a few samples early or late, resulting in doubled or omitted samples. These glitches often sound like tiny repeating clicks during playback. "

.....or into harsher sound due to data correction...
Back to Top
MikeEnRegalia View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: April 22 2005
Location: Sweden
Status: Offline
Points: 21149
Direct Link To This Post Posted: September 05 2005 at 14:02

Originally posted by oliverstoned oliverstoned wrote:

Yes, but software don't suffer from "jitter" problems.

You don'T know what you're talking about. In order to understand it you'd have to get a bit more technical.

BTW: CDex detects jitter and automatically corrects it. And no, it doesn't change anything in the signal. It just reads those passages again until they add up.

One of the articles I posted in the other thread explains it in more detail - basically, jitter is a real time problem. If you were using the CD drive in the computer to just play back the audio (some old drives have headphone jacks), the drives would indeed suffer from jitter. But that has nothing to do with digitally extracted data. In that case jitter can only be introduced during D/A conversion, and in this domain the Creative X-Fi card is very good ... 110ppm, or whatever unit it was.

Back to Top
MikeEnRegalia View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: April 22 2005
Location: Sweden
Status: Offline
Points: 21149
Direct Link To This Post Posted: September 05 2005 at 14:07

Originally posted by oliverstoned oliverstoned wrote:

"Subject: [2-15] What are "jitter" and "jitter correction"?
(1998/04/06)

The first thing to know is that there are two kinds of jitter that relate to audio CDs. The usual meaning of "jitter" refers to a time-base error when digital samples are converted back to an analog signal; see the jitter article on http://www.digido.com/ for an explanation. The other form of "jitter" is used in the context of digital audio extraction from CDs. This kind of "jitter" causes extracted audio samples to be doubled-up or skipped entirely. (Some people will correctly point out that the latter usage is an abuse of the term "jitter", but we seem to be stuck with it.)

"Jitter correction", in both senses of the word, is the process of compensating for jitter and restoring the audio to its intended form. This section is concerned with the (incorrect use of) "jitter" in the context of digital audio extraction.

The problem occurs because the Philips CD specification doesn't require block-accurate addressing. While the audio data is being fed into a buffer (a FIFO whose high- and low-water marks control the spindle speed), the address information for audio blocks is pulled out of the subcode channel and fed into a different part of the controller. Because the data and address information are disconnected, the CD player is unable to identify the exact start of each block. The inaccuracy is small, but if the system doing the extraction has to stop, write data to disk, and then go back to where it left off, it won't be able to seek to the exact same position. As a result, the extraction process will restart a few samples early or late, resulting in doubled or omitted samples. These glitches often sound like tiny repeating clicks during playback. "

.....or into harsher sound due to data correction...

All of this information is outdated. I know exactly what the author describes in the highlighted section. It happens when you read CD data without jitter control. Programs like EAC and CDex detect jitter. They then go back and re-read the section of the CD, going well beyond the point where the laser beam jumped and then comparing the new stream with the old interupted one, ensuring that there are neither doubled, nor omitted samples.

I'm getting tired ... EVERYBODY can verify what I say, nobody can verify your theory. Even you yourself can't verify it, because you won't install CDex and test it.

Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 06 2005 at 03:29
"I'm getting tired ... EVERYBODY can verify what I say, nobody can verify your theory. Even you yourself can't verify it, because you won't install CDex and test it."

That's the same for me. I can prove you by listening what i said. These are not theories, but reality.
Like when you first pretend that tubes amps were not accurate, you eventually admited that there are more than transistor ones; (at least you are not of bad faith)it's the difference between a theory and a fact. Sometimes theories don't match with the results (and only result matters). Of course there's an explanation, and in the case of the issue we are discussing, i will soon provide you new elements.

What i'm sure is that vibrations affect digital reading somehow, another concrete example is you get a huge improvment when you put your integrated cd player or drive perfectly horizontal in the two dimensions(exactly the same than for turntables), you have a dramatic improvment in terms of dynamic, low, image, softness...
cause if the turning machine is not perfectly horizontal, it generates vib' that affects somehow reading...
Back to Top
cobb View Drop Down
Forum Senior Member
Forum Senior Member


Joined: July 10 2005
Location: Australia
Status: Offline
Points: 1149
Direct Link To This Post Posted: September 06 2005 at 03:44
Originally posted by oliverstoned oliverstoned wrote:


What i'm sure is that vibrations affect digital reading somehow, another concrete example is you get a huge improvment when you put your integrated cd player or drive perfectly horizontal in the two dimensions(exactly the same than for turntables), you have a dramatic improvment in terms of dynamic, low, image, softness...
cause if the turning machine is not perfectly horizontal, it generates vib' that affects somehow reading...


This shouldn't be too hard to figure out. The laser is reading pits and land at an exact length. These are microscopic and represent the 0 and 1's. It not hard to figure out that if you raise or lower the cd even minisculey, these pits and lands will not be read precisely.
Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 06 2005 at 03:48
...you can come to listen and i'll prove you all i said.
You can bring Cds as long as there are originals and no "prog"-metal please.
Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 06 2005 at 04:15
Originally posted by cobb cobb wrote:


Originally posted by oliverstoned oliverstoned wrote:

What i'm sure is that vibrations affect
digital reading somehow, another concrete example is you get a huge
improvment when you put your integrated cd player or drive perfectly
horizontal in the two dimensions(exactly the same than for turntables),
you have a dramatic improvment in terms of dynamic, low, image,
softness...
cause if the turning machine is not perfectly horizontal, it generates vib' that affects somehow reading...


This shouldn't be too hard to figure out. The laser is reading pits and
land at an exact length. These are microscopic and represent the 0 and
1's. It not hard to figure out that if you raise or lower the cd even
minisculey, these pits and lands will not be read precisely.


Of course!
and a poor piece of plastic which vibrates can't read as well as a anti resonnant, heavy, rigid mechanic which does like an iron hand around the CD.


Back to Top
cobb View Drop Down
Forum Senior Member
Forum Senior Member


Joined: July 10 2005
Location: Australia
Status: Offline
Points: 1149
Direct Link To This Post Posted: September 06 2005 at 04:15
Thanks Oliver, who's supplying the beer
Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 06 2005 at 04:18
"These are microscopic and represent the 0 and
1's" Yes, and there are MANY o and 1. With a basic mechanic, there are some 0 and 1 unread due to bad mechanic, and which are compensate by corrections circuits.
Back to Top
MikeEnRegalia View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: April 22 2005
Location: Sweden
Status: Offline
Points: 21149
Direct Link To This Post Posted: September 06 2005 at 04:31

Originally posted by oliverstoned oliverstoned wrote:

"I'm getting tired ... EVERYBODY can verify what I say, nobody can verify your theory. Even you yourself can't verify it, because you won't install CDex and test it."

That's the same for me. I can prove you by listening what i said. These are not theories, but reality.
Like when you first pretend that tubes amps were not accurate, you eventually admited that there are more than transistor ones; (at least you are not of bad faith)it's the difference between a theory and a fact. Sometimes theories don't match with the results (and only result matters). Of course there's an explanation, and in the case of the issue we are discussing, i will soon provide you new elements.

Hold on a second ... tube amps are not linear. They ARE more accurate than transistor amps in the higher frequencies, in that they have a higher resolution. But they change the character of the signal more than transistor amps do. I'm not at all saying that this is a bad thing.

Originally posted by oliverstoned oliverstoned wrote:



What i'm sure is that vibrations affect digital reading somehow, another concrete example is you get a huge improvment when you put your integrated cd player or drive perfectly horizontal in the two dimensions(exactly the same than for turntables), you have a dramatic improvment in terms of dynamic, low, image, softness...

Not true. I tried that and noticed no difference. And you're being foolish again, likening analog turntables to digital discs.

Originally posted by oliverstoned oliverstoned wrote:


cause if the turning machine is not perfectly horizontal, it generates vib' that affects somehow reading...

I know exactly what happens. During my time at the university I learned a lot about digital devices. Why can't you admit that you're not an expert?

Back to Top
MikeEnRegalia View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: April 22 2005
Location: Sweden
Status: Offline
Points: 21149
Direct Link To This Post Posted: September 06 2005 at 04:36

Originally posted by cobb cobb wrote:

Originally posted by oliverstoned oliverstoned wrote:


What i'm sure is that vibrations affect digital reading somehow, another concrete example is you get a huge improvment when you put your integrated cd player or drive perfectly horizontal in the two dimensions(exactly the same than for turntables), you have a dramatic improvment in terms of dynamic, low, image, softness...
cause if the turning machine is not perfectly horizontal, it generates vib' that affects somehow reading...


This shouldn't be too hard to figure out. The laser is reading pits and land at an exact length. These are microscopic and represent the 0 and 1's. It not hard to figure out that if you raise or lower the cd even minisculey, these pits and lands will not be read precisely.

25% of the disc's content are checksums, which make it extremely unlikely for a good CD (or CD-ROM) drive to read "faulty" bits. The checksum will not add up, and the drive will read that part again until it DOES add up. Sorry, it's a proven fact which is absolutely bullet proof and undeniable: Modern CD-ROM drives extract the information stored on a CD (-ROM) absolutely precise, with no errors whatsoever. If some parts cannot be read correctly, you'll notice that the drive slows down, makes strange noises (because it repositions the laser frequently) and if the disc cannot be read correctly, the error is reported. There are NO ignored or somehow interpolated errors! 

Back to Top
MikeEnRegalia View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: April 22 2005
Location: Sweden
Status: Offline
Points: 21149
Direct Link To This Post Posted: September 06 2005 at 04:52

Originally posted by oliverstoned oliverstoned wrote:

...you can come to listen and i'll prove you all i said.
You can bring Cds as long as there are originals and no "prog"-metal please.

 I appreciate the offer, but it doesn't work that way. I offered everyone a way to verify my words at home, without even using a subjective impression but rather hard evidence. All you're saying is "trust me, you're wrong" and invite me to travel hundreds of kilometers - and I'm not even allowed to bring the "items in question"? How can I prove my theory if you don't allow me to bring the items we are talking about here?

Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 06 2005 at 05:01
"Not true. I tried that and noticed no difference. And you're being foolish again, likening analog turntables to digital discs."

It's not because you don't hear that it doesn't affects.
On a GOOD turntable with a moving coil for example, on a GOOD AND TRANSPARENT SYSTEM, the difference is dramatic. Only in this case. Always the same pb.

"Why can't you admit that you're not an expert?"
I admit i'm not an expert of the technical field, but i try to explain what i've heard. I don't doubt you have a serious knowledge in your field but you had not the opportunity to do the tests i've made on excellent devices, on several big systems. It's like put a drive or a turntable horizonatl(it also works for speakers-free tip), it works EACH TIME ON A GOOD TRANSPARENT SET UP;so these are not theory, these are facts. You can study digital in a school during years, and conclude that big drives don't work, as long as you haven't HEARD the difference with a direct comparison, you can't tell nothing.
Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 06 2005 at 05:07
Originally posted by MikeEnRegalia MikeEnRegalia wrote:

Originally posted by oliverstoned oliverstoned wrote:

...you can come to listen and i'll prove you all i said. You can bring Cds as long as there are originals and no "prog"-metal please.


 I appreciate the offer, but it doesn't work that way. I offered everyone a way to verify my words at home, without even using a subjective impression but rather hard evidence. All you're saying is "trust me, you're wrong" and invite me to travel hundreds of kilometers - and I'm not even allowed to bring the "items in question"? How can I prove my theory if you don't allow me to bring the items we are talking about here?



Of course you can bring whatever cd you want to test.
This was a joke.
But if you come to Paris for other reason one time, you can come home and i will prove you by FACT all i said.
This will disturb your theories, which are only true...in theory!
Back to Top
MikeEnRegalia View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: April 22 2005
Location: Sweden
Status: Offline
Points: 21149
Direct Link To This Post Posted: September 06 2005 at 05:11

Originally posted by oliverstoned oliverstoned wrote:

"Not true. I tried that and noticed no difference. And you're being foolish again, likening analog turntables to digital discs."

It's not because you don't hear that it doesn't affects.
On a GOOD turntable with a moving coil for example, on a GOOD AND TRANSPARENT SYSTEM, the difference is dramatic. Only in this case. Always the same pb.

No question about turntables ... here you need absolute precision.

Originally posted by oliverstoned oliverstoned wrote:



"Why can't you admit that you're not an expert?"
I admit i'm not an expert of the technical field, but i try to explain what i've heard. I don't doubt you have a serious knowledge in your field but you had not the opportunity to do the tests i've made on excellent devices, on several big systems. It's like put a drive or a turntable horizonatl(it also works for speakers-free tip), it works EACH TIME ON A GOOD TRANSPARENT SET UP;so these are not theory, these are facts. You can study digital in a school during years, and conclude that big drives don't work, as long as you haven't HEARD the difference with a direct comparison, you can't tell nothing.

I don't need to hear in this case. I proof that the data extracted from the CD is absolutely the same as on the CD. I don't need to listen trying to hear a difference if I know that the input is the same. Remember, I'm not arguing that the musical player sounds better. This is only about your assumption that the data ripped from the CD-ROM is flawed.

Back to Top
MikeEnRegalia View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: April 22 2005
Location: Sweden
Status: Offline
Points: 21149
Direct Link To This Post Posted: September 06 2005 at 05:13

Originally posted by oliverstoned oliverstoned wrote:



Of course you can bring whatever cd you want to test.
This was a joke.
But if you come to Paris for other reason one time, you can come home and i will prove you by FACT all i said.
This will disturb your theories, which are only true...in theory!

This appears to be a hopeless case ... by now I've explained in detail repeatedly that this theory of mine can be proven by everyone, without leaving the shadow of a doubt.

Back to Top
oliverstoned View Drop Down
Special Collaborator
Special Collaborator
Avatar
Honorary Collaborator

Joined: March 26 2004
Location: France
Status: Offline
Points: 6308
Direct Link To This Post Posted: September 06 2005 at 05:26
Originally posted by MikeEnRegalia MikeEnRegalia wrote:

Originally posted by oliverstoned oliverstoned wrote:

Of course you can bring whatever cd you want to test. This was a joke. But if you come to Paris for other reason one time, you can come home and i will prove you by FACT all i said. This will disturb your theories, which are only true...in theory!


This appears to be a hopeless case ... by now I've explained in detail repeatedly that this theory of mine can be proven by everyone, without leaving the shadow of a doubt.



At least you let the correction circuit in the shadow.
Back to Top
 Post Reply Post Reply Page  <1 45678 19>

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.402 seconds.
Donate monthly and keep PA fast-loading and ad-free forever.