Why demagnitize an optical reader?


I've read numerous times now that folks state to demagnetize a CD or optical disc before playing it for best fidelity and accuracy.  I don't see how an optical device, which is non magnetic and made from non magnetic materials benefits from a demag process.   Does anyone have any information to support this?  Other than hype, of course.

Robert

128x128spatialking
I don't see how an optical device, which is non magnetic and made from non magnetic materials benefits from a demag process. 

OhOh I feel a spurge of voodooism coming.

Correct  spatialking you cannot de-mag a aluminium substrate (CD), it's non magnetic and it's all voodoo.

You may as well go and de-magnetize all your Al-foil food wrapping or trays to make your food taste better for all the good it will do.
https://www.google.com.au/search?q=al+foil+food+trays&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjx5ZjryKzUAhVLybwKHUUaBZcQ_AUICigB&biw=1509&bih=829

Cheers George