"Eiron" wrote in message

AZ Nomad wrote:

On Tue, 20 Feb 2007 15:31:37 -0000, Pete Cross
wrote:
I noticed a similar effect yrs back when I got a Sony
CDman , I stuck my Alan Parsons sound check cd in and
on the sweep freq test it sounded ok till just past
5KHz when all sorts of harmonics where added, it was
due to the cd spinning at 4x for the read ahead buffer
( anti jog ),must have been sampled at too low a freq, if you turn off
the anti jog it plays fine.


It wasn't from reading the disk at 4x. Reading data at
1x or 200x is reading the same data. As you also
surmised, sampling at too low a sample rate will cause
all kinds of distortion once you get past the nyquist
frequency.

http://www.pcavtech.com/play-rec/Pan_SL-S220/index.htm

Note the adverse effect on IM and frequency response when the shock
resistance feature was enabled.

I thought that the Sony compressed the data before
loading the buffer then uncompressed it on reading from
the buffer, because memory was expensive in the second
millennium.

I was under the impression that in the old days the buffer was not RAM, but
CCD.