This article series analyses the geometrical representation of various signals when being cut/pressed onto a lacquer/vinyl record. It is meant to help understand the physical subtleties of the process.
Part three of the series looks into the representation of noise alike signals on a disk record. Pink noise has similarities with many music signals. Consequently, their groove representation will also tend to look similar.
Near the outer border of the disk, tracking speed is very fast. Thus, the geometry can remain rather smooth and easy to cut or track.
Pink Noise, Mono, 33 1/3 rpm, 12″ inner
Closer to the disk center, tracking speed reduces, whereby the geometry must become substantially rougher to reproduce the same pink noise signal.
Pink Noise, Panned Left
Panned left, only the inner side of the groove will show modulation, the outer side remains flat..
Pink Noise, Panned Right
Panned right, only the outer side of the groove is modulated, while the inner side remains flat..
White Noise
White noise produces aggressive geometry with the physical parts having to reproduce and follow huge accelerations. These high velocities, when sustained over long periods, can overheat and damage the coils of the cutter-head (or hopefully trigger circuit breakers). Even if just appearing over brief passages, high velocities can “inspire” weaker pickup systems to skip details, in turn provoking obvious audible distortions.
