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Wash, Cut, Polish & Demagnetize

As I sat and read through the most recent threads on the "Agon" forum, I noticed a thread regarding "Glossary of Audio Myths". I noticed several comments regarding "greening" and demagnetizing CDs.

Without delving too deeply into the effects of laser light diffraction, deflection, dispersion and reflecting light from adjacent tracks creating "jitter", and to avoid reduntantly examining the fact that the aluminum "wafer" in a CD is not always just aluminum, but in many cases aluminum "alloy", I would like to attempt to dispel a few of these "myths".

Many CD manufacturing facilities use a coating of mold release agents on the manufacturing machinery and on the plastic substrate material in the actual CD to facilitate ease of handling throughout the manufacturing process. Somewhat similar to spraying a cooking pan with "PAM" to reduce sticking. The residual amounts remaining on the CD upon completion of manufacturing should be removed as it will cause minor deflection and loss of focus of the laser beam. Specialty chemicals are available specifically for this purpose. I wash the CDs thoroughly using Dawn dishwashing liquid and very warm water. I cannot confirm that this process is as effective as using the specialty chemicals, but it leaves the CD surface extremely clean and seemingly free from any "oily" feel.

I then cut the edge of the CD using an Audiodesk CD cutter. This process reduces the amount of laser scatter from exiting through the outer edge of the CD and flooding the inside of the CD transport with reflected laser light. By cutting a bevel on the edge of the CD, you actually reduce the edge surface area by which the diffracted laser light can disperse. Some may feel that this a bit excessive, but we must keep in mind that the results of these treatments are cumulative.

The next process involves applying CD "Green" to the beveled edge. The properties of the color value of the Green used in the majority of these coatings tend to absorb any stray laser light. I still, to this day, have not been able to figure out why Green is the color of choice although, I have been told that it is simply the values of each of these colors (Red laser light and Green) that work together in unison to "neutralize" the light. The initial washing of the CD also helps to enhance the adhesion of the green coatings.

Upon allowing the CD green to dry, I then apply CD diamond using 100% cotton balls, and polish using again, cotton balls. CD diamond is an optical enhancer similar to Optrix,
Vivid, etc. and also contains a anti-static component. Most of these "optical enhancers" work by simply filling in microscopic pores in the CD surface permitting a more direct transmission of the laser beam through the plastic substrate material to the actual CD surface.

The last step involves demagnetizing the CD using a Furutech RD-2 CD demagnetizer. CDs, contrary to what most people believe can and will become magnetized. The results are a less black background, a general "haze" and loss of detail. If Cds were made using pure aluminum with NO trace elements, this step might not be required.

The results of all this? Pretty damn amazing. Again, recognizing that the results of all of these steps are cumulative, when all is said and done, the improvement is quite significant. Although these steps may sound somewhat time consuming, each CD actually only takes about three minutes to complete.

I hope I have provided some insight as to "dispelling" some of these myths. I can, and will, stand by this process as time and time again these enhancements have made CDs a lot more listenable. And, I have dropped the jaws of many non-believers after they have heard the actual results.

Any comments regarding this process are welcome. Happy listening.


128x128buscis2
jsawhitlock
302 posts
 
Buscis2, I use cotten lint free wipes for computors and dry them completely and the cotten wipes leave no lint, but I dont notice the haze right a way! The optrix does improve the sound.
There was another person that posted the same experience on another thread. I have tried everything and the haze doesn't remove easily. I also have the CD magic by compact dynamics and that leaves no residue of any kind. I think the optrix replaced the cd magic, and both seem to do about the same as for the improvements. Happy Listening!
herman
2,253 posts
 
Sorry to hijack this thread with a discussion of physics, but I have done a little research into the subject of light absorption and have found the following.

Light will be absorbed by a system when the frequency of the light is in resonance with some natural frequency of that system. When light is refracted, it's speed changes and so does the wavelength, but the frequency does not. Therefore the absorption of a material is independent of the wavelength.
sean
6,231 posts
 
Buscis2: I posted earlier findings about the experiments that i did in another thread. For some reason, i can't find them when doing a search in the Agon archives. It basically details the same experience that i sent you via email.

As to your offer, i already have the potential to perform the same basic tasks that you do during your "digital ritual". I do appreciate your offer, but could save us both time and money by doing the same thing here. As such, i basically have done the same things here and have found that not all of the steps are beneficial as described using my specific equipment.

Herman: I don't think that you are "hijacking" anything. As far as i'm concerned, you are simply doing what these forums are all about i.e. sharing knowledge and comparing notes. I don't think that any of us are against learning something new, especially if it helps us to understand why / how audio reproduction is affected ( for better or worse ).

Having said that, i'm not very knowledgeable about laser technology. If you, or someone else for that matter doesn't mind, can you answer a few questions for us ? These are not trick questions, but that doesn't mean that other questions won't come to mind based on the answers received : )

1) Is the majority of the laser energy reflected back from the disc or is some of it allowed to pass through it to the other side ? I can understand some energy "bending" at the point of impact and "spraying out" the sides or being reflected at right angles of the reflective surface, but my main concern at this point is actual "laser penetration" beyond the disc itself. Do you know if this occurs ?

2) If "laser scatter" ( for lack of not knowing the proper terminology ) is real, what is the best way to minimize the potential for stray light to re-enter the laser ?

3) Is it possible to direct the energy found in "laser scatter" away from the laser or "absorb" said energy via altering the disc itself ?

Bare in mind that i'm not expecting "set in stone" answers, just some idea as to how / why various "tweaks" DO affect the readability of various discs. My thoughts are not so much that they change the sonics of the disc itself, but alter the amount of processing / error correction that is applied to the signal. Does this make sense ? Sean
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herman
2,253 posts
 
Sean, I am not a laser engineer so I can't give definitive answers but I do have a bit of laser experience as I make my living repairing medical lasers. I do have few thoughts on the subject.

Some energy is reflected and some not. That is the way the whole scheme works. Areas that reflect enough light are interpreted as one digital state and those that don't are interpreted as the other state.

When I point my red laser pointer at a disc I see that it scatters the light. Depending on the coating or lack of coating on the top of the disc some discs transmit a portion of the light. I can see it through the disc. Those that have a heavier coating of paint seem to block it. I have no way of knowing if they absorb it or reflect it. The pointer is a shorter wavelength than the laser in the CD player (around 650 nm vs 790 nm) but they are close enough to reasonably assume that they would act in a similar fashion. It is possible to coat a surface with materials that will act upon a narrower range of wavelengths than this so it is possible that my assumptions are wrong.

The big question is whether this scattered/reflected light will be picked up by the sensor in the player and cause errors. It seems like it would be very simple to set up test equipment to capture the bit stream from a digital output and see if it changes with various disc treatments. I don't have this type of equipment so I can't do it but it can't be all that difficult for someone who does. It would be interesting to see what the results of such tests were.
sean
6,231 posts
 
Good info Herman and thanks for sharing. I wonder if these "optical enhancing treatments" are actually a "clouding agent" or "coating" as you mentioned ? By that, i'm thinking that it might be possible for them to apply just enough of a "blocking coat" to minimize the less than full reflective energy that the laser would normally see and read. By blocking anything other than full intensity reflections, "laser scatter" and reflections ( which are probably greatly increased by tiny imperfections in the plastic surface ) would be minimized. That is, at least as far as what the laser is seeing and trying to interpret as data. The laser could now read the primary signal with less outside interference / delayed signal interpretation.

Once again, these are strictly "guesses" and not meant to be interpreted as how these treatments work. As Herman mentions, it would be very interesting for someone that has knowledge of laser technology with test equipment perform some tests of this nature to see just exactly is taking place. After all, the more that we know, the better and more usefully that we can apply that technology. Sean
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