If the effect you are talking about affects the CLV servo then that would be very clear in a fattening of the eye. Given there are no reflective surfaces in an average CD tray I am not convinced there is a problem to fix. maybe balancing the cd to stop vibrations would have an effect?Bill, a standard eye diagram is about data errors, and the method is limited by the resolution of a scope (maybe 1% error or so?). A fancy digital scope might be able to measure timing jitter of the recovered clock though.
Note YBA go a different route with blue light in the tray.
The CD laser light is scattered when it hits the physical data which acts like a diffraction grating. CD rainbow Hel-loo! The scattered light fills the transport compartment, so some of the scattered light can and does get into the photodetector. A lot of the scattered light is channeled through the clear layer and comes out around the outer edge. Also note: the nominal wavelength of the laser is near infrared 780 nm, so theoretically no colors can absorb the scattered light. But if the color of the laser was red, different story, right? Make sense?
The laser servo feedback system cant keep up with the wobbly disc, which is out of round and usually not spinning level whilst playing. The Reed Solomon cannot detect/correct all errors. You guys fell for the “perfect sound forever” marketing ploy hook, line and sinker. 😛
Why did a lot of folks abandon CD? No reply is necessary, it’s a rhetorical question. 🙂
Geoff Kait
Machina Dynamica
not too chicken to change
The laser servo feedback system cant keep up with the wobbly disc, which is out of round and usually not spinning level whilst playing. The Reed Solomon cannot detect/correct all errors. You guys fell for the “perfect sound forever” marketing ploy hook, line and sinker. 😛
Why did a lot of folks abandon CD? No reply is necessary, it’s a rhetorical question. 🙂
Geoff Kait
Machina Dynamica
not too chicken to change
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I keep on bying and playing CDs.All well and good - but a bit moot, as I don't think anyone plays CDs any more? They just get ripped to lossless files, and that process can be guaranteed error free and even if the purple haze ( 🙂 ) on the edge had an effect it's gone by the time it's EAC ripped..
I have rounded the edges with sand paper on many CDs. Black felt pen after that (inner and outer diameter).
I couldn't hear a difference but I kept on doing it while listening to music, like my grand mother was kneeting socks by the fire.

George
Attachments
Personally, I rip CDs too. With high quality conversion to DSD256 they can sound surprising good.
Anyway, so far as I know the question of the felt pen and the CD player has not been scientifically addressed even in self-described technical audio forums. Mostly there has been a lot arm waving and claims more or less to the effect of, "Its impossible for there to be any audible effect." That sort of reaction, when it occurs, is not scientific.
Okay, that makes twice I have considered controversial issues Geoff has been in the middle of, and both times I have found there may be some underlying physical explanation. That's not to say whether Geoff's detailed explanations of cause and effect are exactly right or not. Its only to say that some things claimed to affect sound and or the perception of sound may not be scientifically impossible. They may even be closer probable under certain conditions. Also, I think the way I have framed the issues should probably come close to meeting the testability and falsifiability criteria, at least that would be my intention.
Anyway, so far as I know the question of the felt pen and the CD player has not been scientifically addressed even in self-described technical audio forums. Mostly there has been a lot arm waving and claims more or less to the effect of, "Its impossible for there to be any audible effect." That sort of reaction, when it occurs, is not scientific.
Okay, that makes twice I have considered controversial issues Geoff has been in the middle of, and both times I have found there may be some underlying physical explanation. That's not to say whether Geoff's detailed explanations of cause and effect are exactly right or not. Its only to say that some things claimed to affect sound and or the perception of sound may not be scientifically impossible. They may even be closer probable under certain conditions. Also, I think the way I have framed the issues should probably come close to meeting the testability and falsifiability criteria, at least that would be my intention.
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So who ever tried ripping a CD then making a CD-R copy. Some claimed they sounded better and there was a half credible reason.
Mark4w: “What is the physical mechanism for the purple pen”
I don’t know. By the way, since someone mentioned he does this, black around the outer edge degrades the sound. Does that surprise anybody?
I don’t know. By the way, since someone mentioned he does this, black around the outer edge degrades the sound. Does that surprise anybody?
What is the physical mechanism for the purple pen
I think we would have to do a light absorption spectral analysis for each dye, particularly around the laser frequency. Black ink is often India ink, which looks blue if diluted. That, and as humans we aren't that great as spectrum analyzers. RGB can fool us into seeing most colors. Just because we see purple or see black is only a rough gauge.
Mark4w wrote, “I think we would have to do a light absorption spectral analysis for each dye, particularly around the laser frequency. Black ink is often India ink, which looks blue if diluted. That, and as humans we aren't that great as spectrum analyzers. RGB can fool us into seeing most colors. Just because we see purple or see black is only a rough gauge.”
Go for it, we nervously await your results.
Go for it, we nervously await your results.
[IMHO]
As usual for you, your comment appears to be written in an honest and balanced manner to me, but not everything happens exactly as you describe, or better as you would like it to happen.
....
It should not be allowed to provoke and mock someone and then by pretending that he does nothing.
And if he responds to those who deliberately provoke and mock, then purists don't like him?
This kind of behavior should be prevented, even if they pay the annual fee, not closing an innocent thread.
[/IMHO]
Hi Ulogon,
Thank you for the kind comment. Yes i don't feel the point to be dishonest and i try to respect people overall. Even if i disagree with them as i don't think there is one and only way to do things. Many are possible and as valid as the one we all decided to choose ( or follow) for our own path in life.
That said we are grown up adults and as such responsible of what we say/state. In that if you get challenged on your statements then your responsability to proove or give proof of what you say and as we mainly talk about technical things, answers should track this imho.
I don't feel dishonored by other members behavior. People do what they want, react how they do, i don't really care.
And if a member feels some behaviors are unfair we have moderating crew for this ( report button).
And in my view they do a good job overall: even if i had seen some of my comments moderated in the past despite being a donating member, i really don't think this enter the equation when it comes to forum rules.
In my case i think donation doesn't open to privilege but it help keep the forum independent regarding use of content posted in there. That said i might be wrong, maybe there is a special status to donating members but what i whitnessed in the past tells me not with donating member being victim of stalkers to the point they leaved for some times ( happily they returned back! You know who you are!)...
That said, i'm not into shaming people.
But as soon as you post things in public domain it can be used by others and comes back as a boomerang. Even more when you are doing money with it.
We all dig our own grave, kind of.
Just imagining George in his rocking chair sanding his latest purchases on a winters evening 🙂I keep on bying and playing CDs.
I have rounded the edges with sand paper on many CDs. Black felt pen after that (inner and outer diameter).
I couldn't hear a difference but I kept on doing it while listening to music, like my grand mother was kneeting socks by the fire.
George
Okay, that makes twice I have considered controversial issues Geoff has been in the middle of, and both times I have found there may be some underlying physical explanation.
Who said there has to be a physical explanation? I certainly never did. Especially regarding Herr Schumann. But also the Purple Pen. I probably am in the non physical camp regarding the the use of the color black around the inner CD edge.
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So you give answers to non existing issue? That's it?
Kinda weird to me. 🤔
Edit: well no i got it wrong! As there is no physical explanation the issue is imaterial/ non material. So what could it be? Conscious, spirit related: psychological issue.
Ok got it. 🙂
Kinda weird to me. 🤔
Edit: well no i got it wrong! As there is no physical explanation the issue is imaterial/ non material. So what could it be? Conscious, spirit related: psychological issue.
Ok got it. 🙂
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The effect is not limited to audio. I recommend to loop DVDs, BluRays as well. I don't recommend painting with black or blue, for example, as this will "grease" or "colorize" the image.I keep on bying and playing CDs.
I have rounded the edges with sand paper on many CDs. Black felt pen after that (inner and outer diameter).
I couldn't hear a difference but I kept on doing it while listening to music, like my grand mother was kneeting socks by the fire.
George
What if a purple felt marker on the edge of a CD could do something to affect CD player sound? What might the physical mechanism be?
Given what NAIM did inside their CD mechanism to kill off extraneous reflected laser light, i feel there might be something to it. But ripped onto my HD it makes no difference.
dave
Black ink is often India ink, which looks blue if diluted.
Black is a hard colour for me to get a black colouration to one of the coatings i put on paper cone drivers. India ink is quite blue, in the end i add a tiny bit of black acrylic to the PVA i am uising to get teh right colour.
dave
Who said there has to be…
Please learn to use the quote function. I believe this is the second warning.
It is a pain having to clean up after you.
dave

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