,If your bike has aluminium frame, you can try to attract magnet there and see what happens. Try to attract CD with magnet and see what happens.Is the aluminum frame 100% pure AL or maybe only 99% pure? What about that 1%?
07-09-14: Czarivey
And how about the ink used on the label side? Any ferrous materials there?
Furutech RD-1 CD Demagnetizerhttp://www.iar-80.com/page53.html
The Furutech CD demagnetizer might at first seem to be at the outer fringes of the improbable. Demagnetizing tape heads makes sense for two reasons: tape heads are made from permeable material, and the tape reading process depends on sensing magnetism. But neither of these reasons applies to CDs. CDs seemingly do not contain any permeable material that could become magnetized (neither aluminum nor plastic is permeable), and furthermore the CD reading process does not involve reading a magnetic field. So when we conducted our A-B before vs. after comparisons, we were admittedly biased. We did not believe that we would hear any sonic differences, nor any sonic improvement worth writing about. But hearing is believing. The Furutech is another winner that does make a sonic difference, and it is one of that very rare breed where the difference is entirely for the better.
Like any demagnetizer, the Furutech is intended to be used repeatedly and regularly, perhaps every few plays of each CD. Operation is very simple and automatic. You simply press the button and wait 10 seconds for the light to go out, indicating that the Furutech has completed its cycle. It automatically performs the task of gradually decreasing its demagnetizing field strength during this cycle, so you don't even have to bother with the manual chore of gradually withdrawing your CD away from the magnetic field (as you must do with old fashioned tape demagnetizers).
The Furutech makes your CDs sound more like the new high resolution digital formats. Music's trebles become faster, more extended, airier, and more open. There's a blacker background between musical notes, with better intertransient silence. You can hear more of music's subtle inner details. The natural hall ambience and decay captured by the recording is revealed much better. And music sounds a little more natural, with a little less of the upper midrange glare that characterizes many CDs.
That's a mighty impressive list of sonic accomplishments for a treatment that shouldn't make any difference. So let's investigate.
If we look at the Furutech's sonic accomplishments just above, we might notice that they could all be explained by one factor. If the Furutech somehow reduced the level of contaminating noise, then all the above sonic benefits might follow. Noise contamination certainly fills in what should be a silent black background between musical notes. This degrades intertransient silence, and also veils or blocks music's subtler inner details, which are audible immediately after and between music's stronger transients only if there is a silent background between these stronger transients. Likewise, contaminating noise would obscure and degrade subtle information like hall ambience and decay, which again are audible after and between musical transients only if there is a silent background. Finally, contaminating noise also smears and effectively dulls musical information, acting as a temporally lingering shadow that defocuses music's sharper edges. This is especially destructive of fast treble information, because treble information is by definition more transitory, with sharper edges, so it is more harmed by smearing, lingering shadows, and defocusing than are music's lower frequencies, which have rounder edged waveform profiles, and which tend to be more repetitive.
If CD treatment with the Furutech were somehow reducing some contaminating noise, then we would expect to hear these aforementioned problems reduced - we would expect to hear exactly those sonic benefits which we in fact do hear.
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.
Similar considerations would apply to any ferrous impurities in the aluminum deposited on the CD as its reflective layer.
A simple 10 second demagnetization with the Furutech would erase all these tiny magnets, and thereby would eliminate this source of contaminating noise, providing just the kind of sonic benefits we in fact do hear. Then later, after a given demagnetized CD has rotated fast about 75,000 times, it stands to reason that the ferrous particles in the label and/or in the aluminum might have become magnetized once again, so it would be beneficial to treat that CD to another simple 10 second demagnetization by the Furutech. Incidentally, note that in just 3 plays of a long (74 minute) CD, it rotates fast about 75,000 times. Thus, remagnetization and sonic degradation could begin again sooner than you would suspect. Since it is a pain to keep track of how many times you have played each CD since its last demagnetization, it might be easier to simply demagnetize every CD before each critical listening session, and don't bother before casual listening sessions.
In sum, there is a plausible hypothesis explaining how the Furutech demagnetizer achieves its sonic benefits, and indeed just the kind of sonic benefits that we in fact hear (this predictability and corroboration lends additional credence to the hypothesis). Of course, the most important proof of the pudding is in the listening. The sonic improvements you'll gain from using the Furutech on your CD library clearly make it a winning CD treatment to invest in. (Continued on page 54)
Other articles for you to read.
http://www.6moons.com/audioreviews/furutech/rd1.html
http://www.6moons.com/audioreviews/furutech/rd2.html
http://www.gcaudio.com/resources/howtos/demagnetization.html