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Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ.

The green pen

The Audio Prism Green Pen was a somewhat controversial CD tweak from the 90s that was used to mark the outside edge of CDs (presumably) for better sound. The idea according to Audio Prism was that the color green absorbed stray scattered laser light which would otherwise potentially wind up in the photodetector as real signal. So far, so good.

There are many reasons why the green pen might be controversial, gentle readers, but I would like to help out those who are skeptical because I am skeptical too. The reason I'm skeptical is the color green is the complementary color (absorbing color) for visible red. Yet the CD laser nominal wavelength is 780 nm, firmly in the invisible infrared portion of the spectrum. Colors are not effective in the invisible light part of the spectrum. Complementary colors only work in the visible light part of the spectrum.

Having said that, i find the green pen does improve the sound of most CDs, making them clearer, more dynamic and more natural sounding.

So, what's going on here? Placebo? The laser light is partly red? Something else?



Edits: 06/07/23 06/07/23

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Topic - The green pen - geoffkait 04:03:51 06/07/23 (21)

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