For a number of years audiophiles have reported improvements in performance after demagnetizing CDs and DVDs. Improved clarity and resolution of fine detail, cleaner top-end and a more developed soundstage are common enhancements. Videophiles offer similar reports of improvement related to picture fidelity, color saturation and detail. There is now research to suggest that demagnetization of computer discs (including CD-ROM, CD-R, CD-RW, DVD, DVD-R and other similar disc media) result in reduced block error rates.
When exposed to magnetic fields inside the CD or DVD player, the disc becomes magnetized. While the levels of magnetism may not be great, they are indeed enough to measurably affect performance, as we shall see a bit later.
But wait a second. How, you may ask, can a CD or DVD become magnetized? Good question. On the surface it doesn’t seem possible, since a CD or DVD is essentially aluminum and polycarbonate, neither of which are ferrous materials. However, the inks used to print the labels have been found to contain elements such as Iron, Nickel and Cobalt, which are indeed easily magnetized. Further, while the substrate is 99% aluminum, it may also contain small amounts of the ferrous material listed above.
Without a doubt, I have heard/seen the benefits of disc demagnetization (and likely you will as well). While the performance enhancements are not jaw-dropping, I feel disc demagnetization is clearly a worthwhile practice. Most who have tried it heartily agree, which has spawned several products specifically designed to deal with the problem, and prompted some to experiment with bulk demagnetizers. Let me tell you what I’ve found.
I have spoken with a number of folks who have experimented with bulk demagnetizers, and found their success varies widely. Not surprising, since using a hand-held bulk demagnetizer can be a bit tricky to use. To be effective, the unit must be switched on at a distance from the disc, slowly moved toward the disc, and then similarly moved away in a smooth, gradual progression. Consistent results are virtually impossible as the effect varies with the accuracy of timing and movement. Professional bulk erasers designed for studio use (demagnetization of video and audio tapes) are effective due to electronic control of the process, but they are both large and very expensive. As an alternative, some have tried to use tape head demagnetizers. Due to their small and more directional magnetic field will never produce positive results and their use may in fact only succeed in further magnetizing the disc. Don't waste your time.
The first audiophile oriented company to address the issue was Bedini. We have them to thank for calling our attention to a problem that most audiophiles never knew existed. Their products were effective at reducing the residual magnetism, and over the years we have sold a number of them to satisfied listeners. However, other companies felt better results could be achieved, which led to further research.
To accurately quantify the problems surrounding disc magnetization, the Japanese company, Furutech, invested in research to investigate and document the phenomenon. Using a range of sophisticated measurement equipment, Furutech was able to quantify the amount of magnetism retained on the disc, proving that the problem did indeed exist. Far more interesting, they were able to measure the negative effects magnetism had on playback accuracy; documented proof of what audiophiles and Videophiles had been experiencing for some time.
Testing discs before and after demagnetization revealed measured changes; demagnetizing the discs resulted in decreased distortion, increased signal to noise ratio and increased overall level. Decreased error rates were measured on CD-ROM discs after demagnetization. Note: Furutech has published a white paper with graphs and charts detailing the above information for those interested in the technical bits.
With knowledge that demagnetization was indeed beneficial, Furutech worked to develop an effective demagnetizer, one specifically designed for use with discs in the CD family (DVD, DVD-R, CD-ROM, CD-R, CD-RW, etc). The result of that labor is the Furutech RD-2. Key to the success of any demagnetizer is the ability to smoothly ramp up, then down, the intensity of the magnetic degaussing field. Like the expensive professional models, he Furutech RD-2 uses electronic control for precision and repeatability.
Demagnetization of all disc media can result in improved performance. CD, DVD-V, SACD, DVD-A, DVD-R, CD-ROM, CDR, CD-RW and Photo CD will all benefit from a session with the Furutech RD-2.
Interestingly, Furutech suggests that not just CDs, but the various connectors and cables in a system will benefit from demagnetization as well. According to Furutech supplied information, magnetism is generated in these parts by the current flowing through them. Even though many of the metals used in these parts are non-ferrous in theory, impurities in the materials are enough to retain some residual magnetism.
I must say, the Furutech is easily the best product of its kind I have ever used. I recommend it highly to anyone with a high resolution audio or video system looking to maximize performance. It may not be the equivalent to changing an amplifier, but I would say it is well beyond a subtle tweak. For the reasonable price, the Furutech RD-2 is good enough to be a standard accessory in most every system.
Furutech has discontinued production of the RD-2. Fortunately, Acoustic Revive has taken up the torch and has introduced the RD-3. It's an improved version with even better performance than the RD-2.