Re: arsclist ELP Laser Turntable; Full 3-D mapping of groove?

[Dave Bradley <db65@xxxxxxx>]

> It related to wax cylinders rather than discs.  They need help even more 
> badly.
>
> The technology to play back sound from a digital picture of a groove
> introduces an extra layer of R&D complexity.
>
> It seems far simpler to me that, after repairing the groove image in the 
> computer, that a lacquer disc be cut from the groove image just as car 
> models are sculpted from 3d images created in the computer.
>
> The groove can be lateral and can play back on any decent record player.

Forgive me for replying a couple of weeks late, but I've just been catching 
up.  Taking the groove image from the cylinder and simply placing it into 
the groove of a flat record will cause a number of problems.  #1, the 
record won't be rotating at the same speed as the cylinder, and #2, the 
record's walls don't move at the same speed from start to finish because of 
the radial velocity being larger on the outer grooves and smaller on the 
inner grooves.  So not only would you need to convert the image of the 
groove to the correct speed, you'd then need to also convert that speed to 
adjust for the continually changing radial velocity as it is played from 
the groove of a flat record.  Perhaps reading the image into a wave form 
would be easier.  Or perhaps using the image to cut a replacement cylinder 
that can be played back properly on a cylinder player would be a better idea.




-----------------
Diamond Productions
Specializing in analog tape preservation / restoration in the digital domain.
Dave Bradley   President

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