[John Williamson]

On 17/07/2018 15:31, wrote:

We all know that value - 44.1kHz. That's precisely 44,100 Hertz, not
44,099 or 44,100.3. Sometimes, even on a newer CD player that
can play back mp3s off a disc, something other than desired, is
heard. !

If you ever find a CD drive raw output that feeds the electronics a
constant sample rate of 44,100Hz, I'll probably faint with shock.

What comes out of the drive electronics as a sample stream going into
the DAC has very little connection with what goes into the decoding,
buffering and error correction systems from the laser and detector
system. What comes out is a bit accurate replica of the original input
stream, error corrected, buffered and if not timed by a crystal, is at
least timed by a ceramic resonator.

The same applies to mp3 playback, with a time corrected version of the
original mp3 stream that was fed into the disc burner or flash writer
being fed from the drive into a buffer with error correction built in.
Then the DAC and type conversion gets into play, and outputs what it
thinks the analogue version should be. All clocks in these systems are
normally controlled by a single crystal or use the digital input to the
DAC as a clock source.

--
Tciao for Now!

John.