CD's and DVD's Improving Sound Quality by Reducing Birefringence

By Charles Beresford

In the midst of the digital age, finding ways to achieve the truest possible playback of music and video stored as digital information (audio/video recordings) is never ending. Some audiophiles spend tens of thousands of dollars to gain minute percentage improvements in sound quality. They do this by trying to eliminate as many negatives as possible, which are hampering the original recording. The best components, interconnects, and speakers won’t remove imperfections that are originating from the music source; the CD or DVD. The main objective is to make the disc as stress free and crystal-clear as possible (isotropic). This will allow the laser to read the digital information as it was originally intended.

The polycarbonate, plastic discs, which hold recorded digital information as “pits” and “lands” within the plastic have inherent flaws. It is a natural occurrence in the manufacturing process, that injection molded products (including CDs and DVDs) have built-in stresses due to shrinkage of the molten plastic after it cools in the mold.

Why Stresses In Optical Media Cause Distortions

The reason stresses affect playback quality is due to a phenomenon called birefringence. Birefringence is the refraction of light in two slightly different directions to form two rays (double refraction). Most polymers are optically anisotropic because of the nature of the long macromolecular chains. Anisotropic media shows variation on the direction of action. Polymers are subject to flow during injection molding; therefore, the end product is often highly birefringent due to chain orientation and residual stress. When the single laser tries to read the digital information through the plastic, it is refracted in two directions. This stress-induced birefringence scatters the laser causing poor reading of the digital information, thereby affecting playback quality. These distortions will cause the laser to give you less than the true digital information, which was placed on the disc. This manufacturing induced birefringence causes undesirable effects in many optical applications including CDs and DVDs.

The Manufacturing Process

Once the masters have been completed, the replication process begins. The first stage of the replication process is injection molding. Molten resin is injected against the stamping dies under high pressure. This forms the basic disc structure and embosses the “pits” and “lands” on the “clear” surface. A coat of aluminum or other reflective material is then applied to impart a reflective surface on the disc. An ultraviolet light-curable protective coating is applied to protect the layer surfaces from physical damage and oxidation. With DVD’s two disc halves are fed into a machine where a U.V. bonding agent bonds the two disc halves together. These discs, due to this manufacturing process are now full of stress.

Purity Of Music/Video With Stress Free Discs

What can be done to relieve these stresses that cause birefringence, which distorts the quality of the original information stored on a disc? Through advances from Cryogenics International, it has been discovered, researched, and proven that when CDs and DVDs are deep cryogenically treated, the sound quality improves. This is due to the reduction or elimination of stress induced birefringence.

When these stress free discs are played, the original intended quality of sound emerges. A very big negative is eliminated, by reducing distortions from the point of origin and improving the quality of the disc without altering the music/video. Hear parts of the music you never knew were there. Hear more than you knew was there and see more vividly.

What’s Behind the Benefits of CI Processing?

In the case of many materials, including plastic, Cryogenics International removes stresses through precise, ultra-cold, thermal processing. The removal of these stresses will enable your disc player to receive the original, unclouded music/video as intended on the disc. The quality of sound produced by any stereo system, cable, or component depends upon the purity of the audio signal at its source. All distortions including stresses, no matter how small, change the original audio signal. For truer audio reproduction and crystal clear sound uninhibited by distortions, clarify your discs with Cryogenics International.

Cryogenics International will deep cryogenically process your new or used CDs and/or DVDs, enabling you to hear music as it was originally intended; Clearly superior playback!