What is wrong with Audiophiles?

FYI, for most folks, is that in the original Philips CD player design..which was the basis for all digital signal reproduction of audio signals  in the environment of home playback ..for almost two decades....that the clock and timing is recovered from the optical reading of the disc.

So, in effect, the optical read quality combined with the mechanical perfection of spin, combined with the quality of the disc itself, in build, disc plastic, labels, optics, etc...becomes, at a minimum... the digital clock jitter itself.

Which in turn, affects the signal reconstruction and becomes the sound quality that we hear and heard.

So, in original non buffered design in cd players (early 80’s to the late 90’s) and associated dacs..the quality of the discs and playback..and all of the hardware, becomes the quality of the music you hear.

Bits are not bits in this case, due to the way the hardware/software worked.

And that is how green markers made a difference for such systems. And how mechanical isolation, disc mats, etc..all contributed to making for better digital audio. As a legacy system, and how discs are read now, some of that still has an effect in physical disc read, in some systems.

Not sure I agree with your detective work, Teo. for one thing Red Book CD Standard was developed by Philips AND SONY. It became the International standard for CDs in 1987.

Standard[edit]

The Red Book specifies the physical parameters and properties of the CD, the optical "stylus" parameters, deviations and error rate, modulation system (eight-to-fourteen modulation, EFM) and error correction facility (cross-interleaved Reed–Solomon coding, CIRC), and the eight subcode channels. These parameters are common to all compact discs and used by all logical formats, such as CD-ROM. The standard also specifies the form of digital audio encoding: 2-channel signed 16-bit Linear PCM sampled at 44,100 Hz. Although rarely used, the specification allows for discs to be mastered with a form of emphasis.

The first edition of the Red Book was released in 1980 by Philips and Sony;[1][2] it was adopted by the Digital Audio Disc Committee and ratified by the International Electrotechnical Commission Technical Committee 100, as an International Standard in 1987 with the reference IEC 60908.[3] The second edition of IEC 60908 was published in 1999[4] and it cancels and replaces the first edition, amendment 1 (1992) and the corrigendum to amendment 1. The IEC 60908 however does not contain all the information for extensions that is available in the Red Book, such as the details for CD-Text, CD+G and CD+EG.[5][6]

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1) The semiconductor laser used in CD players has a nominal wavelength that varies about +/- 10nm, i.e. it could be between 770-790nm, however, the bandwidth is very narrow, and will be down >40db within 5nm of the nominal wavelength, and typically within 2-3nm. So that CD laser diode output is worst case about 765-795. There will be no, almost no visible light in a 780nm laser diode.


2) Saying "colors" only affect light in the visible spectrum or that "black" does not absorb infrared light is also incorrect. Ink color indicates what colors in the visible spectrum is reflected (black poorly reflects everything) or not absorbed. It does not indicate what happens in the near-IR (780nm). You can’t say carte-blanche what will happen in the near infrared. Most black inks absorb Very Well in the near infrared (780nm). For green, it would be more variable.

geoffkait18,317 posts11-18-2019 5:38amBoxer, black should never (rpt never) be used on CDs except for the inner edge. The color black on the outer edge hurts the sound. The color black doesn’t absorb infrared light anyway. Also, the color black should not be used for the label side where it also hurts the sound. Unfortunately, some CDs have a black label. And the colors used in the graphics of CD labels affect the sound because they influence the scattered light. The color Black should always be used for the inner edge. As fate would have it no colors, including black, can affect the invisible infrared scattered light which, as I mentioned is 75% of the scattered laser light. The bandwidth of the CD laser is around 650-850 nm. Nominal wavelength 780 nm. Colors only affect light in the visible portion of the spectrum. A color’s complementary color absorbs that color. So, Turquoise (Cyan) absorbs Red, for example.

You are incorrect. The CD laser actually appears red 🚨 to the naked eye 👁 as a safety feature. So, obviously there must be RED light in the laser spectrum. Which means, now follow me here, the wavelength of the laser spectrum must be well below 700 which is where visible red starts. Thus, it’s reasonable to conclude the lower portion of the CD laser bandwidth extends down to 650 nm. That’s why I say the laser bandwidth is around 650-850 nm. And that is also why I say most of the scattered light is invisible. The cheap little laser and photodetector are not monochromatic, all of which fits perfectly into the proposition I stated.

The other obvious reason we know there is visible red in the scattered laser light is because the color green or turquoise (cyan) absorbs the color red, and that’s why a green marker around the outer edge improves the sound and why coloring the CD tray turquoise improves the sound. It absorbs red light. The color wheel applies to visible 👀 light only. As I said BLACK anywhere on the CD hurts the sound. It can be easily demonstrated experimentally.

But don’t let me stop you, I always enjoy hearing from Cargo Cultists to see what kind of ridiculous things they come up with. 🤗

Here is a simple challenge for you geoff ...

Go find a spectrum for the laser diode in a CD ... should be easy. Now look at that spectrum.

There is not visible red in the spectrum of the laser, and yes, that cheap laser diode, like all laser diodes are pretty much monochromatic unless designed otherwise. It is not a super sharp wavelength single mode, but even a dirt cheap multi-mode is monochromatic. There may be leakage in the 700-720nm, but it is almost none and would required a dark room to see. Many transports added a red diode inside the assembly to give people comfort "something" was happening. Since the optical detector is focused on the spot, minor stray light is not much of an issue. Look at the second half of this video and how hard it is for the person to even detect the CD laser:    http://www.youtube.com/watch?v=Df70YVAg-iI

Many green inks will absorb 780nm. That proves nothing at all except that people who promote things like using green ink (as opposed to some other color) don’t understand much about absorption spectrum of dies and inks. Let’s not forget the optics are also focused, so most scattered light is rejected.

And you are wrong, almost all black inks will absorb 780nm. Again easily proven, just look up absorption spectrums of black inks and dyes. The "color-wheel" only tells you what happens when the light is visible. It tells you nothing about what happens to light on a colored substance when you use non-visible light. You are guessing at what happens and guessing wrong.

All the ad-hominems in the world will not change that You Are Wrong. You keep slinging ad-hominems, I will keep slinging verifiable facts. Let’s see who most people believe.