Digital Audio Myths - Listening on a PC

"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...

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.

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

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

 Come on oliverstoned, there's no arguing about this particular issue. Mind you, we're only talking about the extraction of the digital information here. The musical CD player does much more:

• upsampling
• D/A conversion

I firmly believe that in these two areas the computer has a long way to go until it sounds as good as a musical CD player. But the EXTRACTION of the audio is a really simple process. Too bad that a lot of people are suckered into believing that in order to extract information properly from CDs, the same amount of mechanical precision as required for vinyl as to be done. It's just ridiculous.

BTW: What makes you believe that audio CDs contain more information than CD-ROMs? CD-ROMs can be extracted without any error (obviously, because otherwise the programs wouldn't work anymore), so why do you refuse to believe that audio CDs cannot be extracted? A data CD-ROM is basically an audio CD with one huge track. The method to read audio CDs is EXACTLY the same as that for reading CD ROMs ...

^ Exactly.

The article is just wrong. Unfortunately my browser just hosed a more elaborate reply ... but here's a short summary:

Conduct a little experiment:

• Install CDex, configure it for "Full Paranoia" extraction mode.
• Insert an audio CD, preferably one with some scratches.
• Rip one of the tracks to WAV, stored on the hard disk.
• copy the extracted track to another folder/filename and repeat the previous step, shaking the computer a little bit. If what the article says is true, this should result in subtle mistakes in the ripped files.
• Compare all the extracted files ... I'm sure they'll be perfectly identical. Unless CDex signalled an error, if the CD is too badly damaged.

There, all proven wrong. And EVERYONE who has a computer with a CD-ROM drive can conduct this experiment, not just people with esoteric equipment.

MikeEnRegalia wrote: I know all about digital technology. In the digital domain, there are NO mechanical, electromagnetic or acoustic problems. It's only bits and bytes. Sorry, but if you don't believe me ask any expert you trust. The ONLY complex part in the digital domain is the algorithm.

Not as simple!
Here's an article from "What hifi" (english magazine) which explains why a cd copy is less good than the original(they don't talk about good burners) and it's also about CD mechanic problems.
They say what i told you: the smallest vibration disturbs reading and it makes corrections circuits works, which recreates an aproximative signal.
I was right!

"Why CD-R and Minidisc copies can sound different from the original
The term 'digital' has been used by the marketeers to equate with 'perfection' - but there's still a lot that can go wrong...

Our recent reviews of various CD-RW and MiniDisc recorders have attracted a flurry of correspondence, much of it via e-mail, denouncing the results we reported. 'How can different CD-RW discs/MiniDisc blanks/CD-RW recorders sound different?' they howl, adding, 'Surely the machine/disc combination either records the ones and zeroes or it doesn't. After all, different floppy discs don't make word-processor documents read better or worse, do they?'

It's hard not to argue with that last bit of logic, even if sometimes the reviewing staff on the magazine would love to be able to blame their floppies (!). But experience has taught us that, just as different CD players impose their own sound on a recording, so the various digital recorders on the market, and even the various brands and types of blank media available for them, can make a difference.

So what's going on? Digits are either there or not, right? The answer to that is 'kind of...' since all digital systems rely on error correction to get the sound from the disc to the analogue outputs in a recognisable form. The less hard the correction systems are having to work to reconstitute the original sound, the better the reproduction becomes.

What's being corrected is faults in the data, caused by anything from scratches on discs to mistracking of the laser pickup, from fluctuations in disc speed to wobbles in the spinning disc, and from low reflectivity causing misreading to vibrations caused by someone walking across the room. And that's before you get into electronic failings such as jitter...

Trouble is, a CD or MD player looks dead simple: you bung in a disc and it just plays music, just like these words are about to be saved to a hard disc on a computer and when we want to read them they'll come back on the screen exactly as they were typed. Hopefully.

But the fact of the matter is that CD players, and digital recorders, are all about high-precision engineering operating in a fairly hostile environment. For example, the laser pickup system in a CD player, or the write head in an optical or magneto-optical recorder, needs to move in three dimensions, alter its power and focus, and deal with a disc spinning at a constantly-changing speed, and do all that on a microscopic scale.

Thus anything that can make this task easier, be it discs with greater reflectivity, more even spirals of pits, or even a more consistent optical layer, is likely to give a better sound.

No, all digital equipment doesn't sound the same, however much logic might suggest otherwise - in fact, it's a miracle most of it is so consistent... "

WhatHiFiSound+Vision

I know all about digital technology. In the digital domain, there are NO mechanical, electromagnetic or acoustic problems. It's only bits and bytes.

Sorry, but if you don't believe me ask any expert you trust. The ONLY complex part in the digital domain is the algorithm.

oliverstoned wrote: It's very complicated to do a musical converter.

It's a completely digital process ... there's no reason why it shouldn't work on a computer. Unless the algorithms are kept secret by the manufacturers of musical CD players, that is.