sonddek
Trade: SUPATRAC
BTW, using measurements from this page:
http://www.vinylengine.com/phpBB2/viewtopic.php?t=22894
...I reckon that a typical modern stylus generates an inner groove error of about 0.4 micron. Distance between mean points of contact: 24 microns
Phase error: 24 microns x sin(1 degree) = 0.42 microns
A 20kHz signal in the inner groove gives a wavelength of about 20 microns, calculated as follows:
radius: ~0.1m
groove speed: 2 * Pi * 0.1m * 100/180 = ~.35 m/s
Divide by 20,000 for 20kHz wavelength = ~17 microns
So the phase distortion is about .4/20 of a wavelength, i.e. 1/50th of a wavelength at 20kHz at the very innermost groove. And don't forget, this is only a phase mismatch at very high frequencies. Good luck hearing that.
Across the great majority of the record it's much smaller or zero. This is probably why experienced enjoyers of affordable elliptical and better styluses are not complaining about this issue.
http://www.vinylengine.com/phpBB2/viewtopic.php?t=22894
...I reckon that a typical modern stylus generates an inner groove error of about 0.4 micron. Distance between mean points of contact: 24 microns
Phase error: 24 microns x sin(1 degree) = 0.42 microns
A 20kHz signal in the inner groove gives a wavelength of about 20 microns, calculated as follows:
radius: ~0.1m
groove speed: 2 * Pi * 0.1m * 100/180 = ~.35 m/s
Divide by 20,000 for 20kHz wavelength = ~17 microns
So the phase distortion is about .4/20 of a wavelength, i.e. 1/50th of a wavelength at 20kHz at the very innermost groove. And don't forget, this is only a phase mismatch at very high frequencies. Good luck hearing that.
Across the great majority of the record it's much smaller or zero. This is probably why experienced enjoyers of affordable elliptical and better styluses are not complaining about this issue.