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RE: So what's the deal with CD demagnetizers?

Exactly why or how it works I don't know.

From personal experience and experimenting I found it does work.

I have a old Bedini Ultra Clarifier. I used to have a web link of the patent Bedini applied for when he invented the thing but lost it years ago and have not been able to find it since.

Bedini did not say it demagnetized the disc. It aligned something.

Yes CDs can be magnetized. Some more than others. Yes the ink/dye used on the label can have ferrous materials in it. Even the aluminum disc can have impurities in it that are ferrous/magnetic.

What I found from experimenting.

Labels that use dark, brown, red, blue, black, and green, can be magnetized.

A spin in the Bedini, both sides, can have an impact on the SQ of the CD.

A tape demagnetizer will have a slight change on the SQ of the CD but not as much as the Bedini.

A simple test if you have a CD with a dark color label, say dark red or dark blue. You will need a strong permanent magnet.

First listen to the CD to familiarize yourself with it again.
Next take the strong permanent magnet and move the magnet over both sides of the CD without actually contacting the CD.
Next play the CD again and listen for differences in the CD.

I have recorded an untreated CD on a CD-R music recorder and then given the same CD a spin, both sides, in the Bedini and then recorded it again on another blank CD-R music disc.

The two finalized CD-R CD clearly sound different from one another. I have even taken an untreated CD and recorded a few songs on a CD-R, then treated the CD in the Bedini and recorded the same songs on the same CD-R CD. Finalized the CD-R and again the recorded untreated songs clearly sounded different than the treated recorded songs.

I have even taken the recorded CD-R/s to a B&M Dealer in my area and played the CDs on his equipment. Marantz and Cambridge CDPs. There was no mistaking the differences in sound of the CDs.

I also found CDs with a silver color label, the Bedini made little difference or none to the sound.

I also found if a silver color label CD sounded bright, like some in the early 1990s a spin, both sides, in the Bedini made the CD sound even worse.

Here is one for you. I Found if a finalized CD-R was given a spin in the Bedini it dulled the sound and basically ruined the CD-R CD.

If a blank CD-R was given a spin in the Bedini first before is was recorded/burned the Final product sounded fine.


Quote from link below.

Furutech RD-1 CD Demagnetizer

Now, how on earth might the Furutech somehow reduce contaminating noise? What is there in a CD that might cause contaminating noise, and that might need demagnetizing? And how does a CD get re-magnetized by being played, such that it benefits from further demagnetizing after a few plays?
The Furutech people have two simple answers. Ink and impurities. The whole surface of a CD is covered with ink, to make up the printed label. These inks contain pigments, some of which are ferrous, hence permeable. The Furutech people also suggest that the aluminum in the reflective layer might well contain impurities, including iron.
Now, the CD rotates pretty fast (200 to 500 rpm), and any ferrous material will gradually become slightly magnetized over time if it is rapidly moving in a magnetic field (the earth's magnetic field will do, but there are doubtless other magnetic fields as well within a CD player). All right, so we have a CD with some slightly magnetized pieces of ink, spinning around inside your CD player. How does that cause contaminating noise in your music?
Let's assume that the brown pigment in brown ink is ferrous, and let's assume that some small lettering on the CD label is printed in brown ink. Let's assume that there are about 50 letters in the small lettering, which means that there are about 100 vertical ferrous bar magnets (for example, the letter H has two vertical bars), rotating around with the CD. These rotating bar magnets are putting an electromagnetic noise field into the space and air inside your CD player. If the CD is rotating at 8 Hz (480 rpm), and there are 100 discrete bar magnets going around at 8 Hz, then they are putting out noise with a fundamental at 800 Hz, together with all kinds of overtones spread upward throughout the rest of the musical spectrum (if we were to assume the bar magnets were purely rectangular and put out noise that looks like a square wave, there would be overtones at 2400 Hz, 4000 Hz, 5600 Hz, etc.)

You can see that this contaminating noise thrown into the air is rich in high frequency spectral content, so it would be most destructive of music's higher frequencies and of singular, non-repeating musical transients, if it were to somehow interfere with the music signal inside your CD player. And, if a CD treatment like the Furutech could reduce this high frequency contaminating noise, then we would expect to hear the sonic improvements being most dramatic for music's trebles and for its singular transients - which is exactly what we do hear.
Given that this noisy electromagnetic field is radiating into the space and air inside your CD player, how could it come to actually contaminate your music? After all, your music signal is safely traveling inside the conducting wires of the CD player's circuitry, isn't it? So who cares if there's spurious electromagnetic noise in the air outside these wires, right?
Well, it turns out that electromagnetic fields in the space and air just outside your CD player's wiring can also penetrate into that wiring, so if that field comprises contaminating noise, then that noise can add to or interfere with the signals in your CD player's wiring. The analog circuitry in your CD player is certainly vulnerable to signal degradation by interference from noise, but so also is all the digital circuitry in your CD player. Why? First, that so-called digital circuitry is actually analog circuitry, operating with precise thresholds and precise currents, whose level and/or precise timing can be contaminated, degraded, or made less determinate by noise. Second, it is now widely recognized that merely adding noise to a digital signal in your CD player can worsen jitter (by making thresholds more temporally indeterminate), which in turn worsens distortion of your music when that timing indeterminacy reaches your DAC chip. If the interfering noise has high frequency content, then this can cause high frequency jitter, which is especially destructive of music's higher frequencies, causing smearing kinds of distortion (from FM distortion sidebands spread over a wide and high frequency range).
Furthermore, it turns out that the desired signals running around in the wiring of your CD player are not really traveling inside the wires, but instead are actually traveling as electromagnetic fields in the space and air outside those wires - in the very same space and air also occupied by the noisy electromagnetic field from those spinning magnets on the CD. Since the desired CD player signals, representing your music, and the noise from the spinning CD magnets are both mixing it up in the same space and air, naturally there is cross contamination.

Is the spinning CD a spinning dynamo?

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