Eeyore wrote:

mick wrote:

Eiron wrote:
mick wrote:
Trevor Wilson wrote:
"Eiron" wrote
Trevor Wilson wrote:
"Iain Churches" wrote

I am told that the HK does not have even
a pitch control. Many serious listeners, especially those with an
accurate sense of pitch require this.
**Are you suggesting that the recordings are faulty? That is the
only way a CD player can play at the wrong speed. Pitch controls are
of no use for domestic listening. I've seen DJs use them, however.
The speed of a CD player is only as accurate as its quartz
oscillator. I wouldn't be surprised if a player could gain or lose a
tenth of a second during an hour, and vary with temperature. Not that
it matters for normal listening but it makes comparisons difficult.
**A cheap crystal would suffer such poor figures.


I think it would have to be *very* cheap or an R/C oscillator! That's
about 0.17% error or 1666ppm. Even a ceramic resonator would typically
be better than 100ppm over any sensible temperature range. There is *no
way* that anyone is going to detect that sort of error using ears. IMHO
a pitch control on a CD player is an unnecessary gimmick to give the
snake oil fans something to crow about. ;-)
I suggested 0.1 second per hour, not per minute, so 28ppm not 1666. My
cheap non-adjustable Casio wris****ch is accurate to about 10ppm so it's
the right range for an unadjusted quartz oscillator. I think I'll do
some measurements and find out the truth....
oops! sorry - forgot the other 60... :-(

It hasn't changed my view on pitch controls though - 28ppm is very, very
tiny. I doubt if even those with "perfect pitch" could reliably detect a
frequency error of 100ppm (0.1Hz at 1kHz), never mind 28ppm without
something else to compare it with - not a likely circumstance when one is
attempting to listen to the music! The pitch control is only useful to
those attempting to compare players. :-)

1 cent of pitch ( one hudredth of a semitone) is a little over 500 ppm.

28ppm or 100 ppm will most certainly be inaudible.


I tried a little experiment - playing 1kHz test tones from two CD players
into a dual-trace oscilloscope. ( Actually a software 'scope from
http://www.virtins.com )

The results,

MP3 player: 22ppm slow
Pioneer DV696AV: 12ppm slow
Marantz CD273: reference
Pioneer PD8700: 365ppm fast

I don't know which player has the most accurate clock but it is surprising
that my trusty old Pioneer should be so fast, gaining about 1.3 seconds
in an hour. That's possibly why my wife didn't like it. It must be on
the verge of audibility for someone with perfect pitch.

--
Eiron.