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In Reply to: RE: So what's the deal with CD demagnetizers? posted by mkuller on November 11, 2015 at 14:37:53
The static electricity is a separate issue. More on that later. But back to the question, how can the metal layer be magnetic to any REAL degree? It is sputtered on so the layer is extremely thin. You can sometimes SEE through it it's so thin. In addition the aluminum or nickel or gold layers are quite pure. If there are ANY ferrous impurities at all in the metal layer - which is dubious - there could not possibly be enough magnetism to account for much of anything. You might as well suspect the polycarbonate of impurities. Now, if someone said that 24 carat Gold CDs were impervious to demagnetizers I might go along with you as far as aluminum or silver or nickel CDs go. As for your question regarding magnetism in LPs, I suspect the same argument applies. There doesn't appear to be sufficient ferrous impurities in either the vinyl or the ink on the label to affect anything sonically or to be affected by a demag.The other problem of course is, even if there were sufficient ferrous impurities in the metal or the ink to produce a "mild" magnetic field WHAT would the magnetic field affect that changes the sound? Is it the electronics, the laser beam (yes, I know it's electromagnetic), the servo mechanism, what?
Nevertheless, I employ both a demagnetizer and a tourmaline negative ion gun on CDs simply because I believe it's better to be safe than sorry. Hahahaha
You wrote,
"After all we are talking about optical optimization on a microscopic level."
That's assuming the magnetic field, if there is one at all, affects the optical reading process and not something else. And even if there is a slight magnetic field and it DOES affect the laser reading process it better do it VERY QUICKLY since the photons are moving at the speed of light and the distance they travel between the laser output and the photodetector is what about half an inch? :-)
Edits: 11/12/15 11/12/15 11/12/15 11/12/15Follow Ups:
"The other problem of course is, even if there were sufficient ferrous impurities in the metal or the ink to produce a "mild" magnetic field WHAT would the magnetic field affect that changes the sound? Is it the electronics, the laser beam (yes, I know it's electromagnetic), the servo mechanism, what?"
I'd say, from past dinking that the issue is prolly electrostatic. With a zero stat it's easy to deposit charges or remove them (if you're close, the discharge directly sticks to the surface, if you are at the "normal" working distance the ionized air plume equalizes them) and with a dog hair electroscope you can readily detect them. Now don't get upset if you're a cat person, their hair would prolly be JUST as good. Human too but I don't have any to spare, sigh. The construction is: tape a hair to a toothpick with scotch tape. Elegant...
The obvious? next step would be to lay down strips of charge and monitor the focus coil current with a scope to see if you can see their pattern. But I did't get that far since I was going to just rip everything. But I've since discovered that I'm rather fond of just playing CD's so may revisit it.
"Nevertheless, I employ both a demagnetizer and a tourmaline negative ion gun on CDs simply because I believe it's better to be safe than sorry. Hahahaha"
I'd bet on the ion gun but would surely like to know if it's the demag.
Rick
We had tools to actually MEASURE the amount of electrostatic charge. Calibrated for a certain distance, we'd use it AFTER a good blast of ZeroStat.
We were VERY concerned with ESD and all the rest in a manufacturing environment.
Too much is never enough
Electrostatic charge is another issue entirely. The earnest audiophile must both demag and use some sort of anti static treatment. Better safe than sorry.
I'd personally be more concerned with ElectroStatic charge. I've measured particles on bare Si wafers and found that Electro Static air treatments make a HUGE (several orders of magnitude) difference. Charged wafers are simply particle magnets. As I'd assume a CD/DVD/BR to be. Or even an LP, for THAT matter.
This was in a class 10 room. Cleaner than ANY operating theater, but NOT sterile.
Too much is never enough
But I question electrostatic charge as being a problem, too, just like I question magnetism and demagnetizing the disc. It's not too difficult to see where the static charge on a disc arises but what is the effect, how does it hurt the sound? Static charge is a magnet for particles of opposite charge, that's true. But so what? How does it affect the sound? Certainly not by affecting the laser beam.
A clean disc is a happy disc.
I would use the Zero Stat to remove dust / reduce dust buildup.
I doubt much or ANY actual audio degradation at least until the point of obscuring the laser.
Too much is never enough
Sorry, not buying it. Never see any dust on any CD. Besides the static charge builds back up and one must resort to anti static measures once again at some point to restore the sound. Yet there is no dust inside the player, it also doesn't explains why destat improves record play since dust is not really an issue for records, is it? And it doesn't explain why removing the static charge from interconnects improves the sound.
again, assuming 'facts' not in evidence.
One of the MAIN reasons I gave up vinyl in about '84 was all those ANNOYING pops and ticks. In extremely DRY climates, I suspect it is even possible for the electrostatic charge to effect Tracking Force.
In the interest of COMPLETENESS:
(I would use the Zero Stat to remove dust / reduce dust buildup) IF i ever had such a problem.
I experimented BRIEFLY with pop / tick removal. Maybe 45 seconds. I JUST 3 weeks ago gave away a good DBX NX-40 compressor / expander which found use on a R-2-R but I NEVER succeeded in finding a DBX encoded disc.
CD is not very susceptible to such dust. DVD moreso, due to the smaller 'pitch' of the geometry and BR perhaps even MORESO. That being said, I've NEVER in 30+ years of CD ownership EVER had an issue I could ascribe to dust or such buildup. My ORIGINAL 3 discs including a wonderful Eric Clapton Blues Breakers has NEVER had a single issue. The garage sound of that that disc is wonderfully preserved and reproduced.
Too much is never enough
Well, you somehow managed to totally confuse me. On one hand you say electric static charge attracts dust then you turn around and say CDs do not attract dust. Color me confused. In any case, there is no doubt that both demagnetization of CDs and LPs and interconnects is beneficial to the sound. And so is the use of ionizers like my Particle Accelerator or anti static sprays such as my Sonic Tonic or Nordost anti static spray. It's just the operating mechanism that we are only guessing at. Don't get hung up, just keep moving, it's hard to hit a moving target.
I honestly don't know how you can listen to those things without demagging them. I suppose one can get used to anything.
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