"Norman M. Schwartz" wrote:

"Pooh Bear" wrote in message
...
"Norman M. Schwartz" wrote:

wrote in message
...
Mike Prager wrote:
Perhaps it's time for the group to split into two:
rec.audio.high-end and rec.audio.high-end.haters.

Why? Because the guy asked how much jitter it takes to be audible, that
makes him a hater of high-end audio? Do "high-end lovers" think that
question is unimportant or irrelevant? Do you?

It's going to take a lot (whatever the electro-physico explanations). In
the
early days of CD, when there were only 1 box units available to play
discs,
golden eared high enders were endorsing 2 boxes; drives and D/A
converters
to get superior sound. Isn't that where jitter entered the picture? One
box
delivered better (jitter free) sound.

By basic principles ( lack of need for a clock recovery circuit ) the
potential
for a 1 box solution to be superior in respect of jitter is indeed true.

Just depends how clean your system clock is.

OK, and my point was/is that the listener who wanted the best and latest
equipment for listening to CD was told (by insiders having good and trained
ears) to go out and replace their adequate single boxes with two boxes with
added jitter.

Clearly, said sources don't understand the basic engineering principles behind
the technology. Since it's not entirely obvious ( least of all to the man in the
street ) and there's a big market for said 'aftermarket' products I'm
unsurprised.

It is potentially conceivable however that a single unit CD player might have
poor inherent system clock jitter and an outboard converter has a great PLL with
very good jitter rejection that does indeed improve the result.

That's an extreme case - but I'm sure it happens ( most likely in the past ) .
And the converse could be true too.


So therefore "jitter" in *practicality* was/is a red herring,
and that they didn't hear the deleterious effect of jitter. Do you think
anyone can suffer by the presence of jitter today (please no DBTs )?

Today ? I guess that cheap consumer gear may well suffer jitter induced defects.
There's no excuse for *well designed* high end gear to suffer.

Incidentally - the bit pattern used by SPDIF or AES/EBU is inherently subject to
signal dependent and cable length dependent jitter at the receiver even when
there is *no* jitter at the transmitter. It's down to the encoding method.


Graham