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NEW!! Dark Matter Optical Coating for CDs

What You Can't See

Copyright June 2013 .... Geoff Kait

Dark Matter Optical Coating is the first audio product to address the (generally unrecognized) problem in CD playback produced by invisible, infrared scattered laser light inside the transport compartment. Dark Matter is a permanent optical coating that is applied to the LABEL SIDE of CDs using a spray bottle. The liquid evaporates quickly leaving a thin, clear optical coating. Dark Matter absorbs background scattered infrared light that could otherwise make its way into the photodetector as noise. Since the laser scatters light all around inside the CD transport compartment, the CD label is an effective location for Dark Matter.

Dark Matter Optical Coating is a transparent, emerald green liquid that comes in a 3 oz spray bottle, sufficient for treating 125 CDs. Place a Bounty towel under the CD in case of overspray. Hold the bottle 3 inches from the CD, spray Dark Matter onto the LABEL SIDE using 4 pumps of the spray bottle. Allow Dark Matter to dry for 5 minutes or until completely dry. Drying time depends on temperature and humidity of the ambiant air. Dark Matter dries clear, forming a long-lasting thin film. Dark Matter can be applied to the top surface of the CD tray for additional benefit. Dark Matter is designed ONLY for CDs and will not work for DVDs, SACDs or Blu Ray discs.

Diagram 1 - Electromagnetic Spectrum Showing Visible and Invisible Portions, Including Near Infrared (NIR).

Dark Matter absorbs invisible background scattered light inside the CD transport that is produced when the CD laser reads the physical data (lands and bumps). The reason background scattered light, whether visible red or infrared, degrades the sound is because some of the scattered light makes its way into the photodetector where it is misinterpreted as real signal. The photodector in the CD player is designed to accept any light that is more than 70% of the full reflected signal (power) from the CD. The CD laser's nominal wavelength of 780 nm is in the near infrared, an invisible portion of the electromagnetic spectrum. Diagram 1 above illustrates the relatively narrow color portion of the electromagnetic spectrum, between 400-700 nm. Coloring CDs improves the sound because colors, especially green and blue-green (red's complement) affect the visible red color portion of the scattered laser light - the laser is not, strictly speaking, monochromatic so there is some visible red in the background scattered light. However, the infrared scattered light - because it's invisible - cannot be influenced by color, i.e., there is no complementary color for infrared light. So other means must be employed to absorb it before it can reach the photodetector (which is not monochromatic, either). The invisible portion of the CD laser scattered light is circa 700-900 nm. Dark Matter is a powerful optical coating that absorbs invisible NIR scattered light. Since the background scattered light is everywhere inside the CD transport, the CD label is an effective and convenient location for applying the optical coating.

3 OZ Bottle Dark Matter $99, treats 125 CDs. Sample Size $20, treats 10 CDs.