> Good points.
>
> If I understand your first point, you and Pat are asking for someone to
> either perform a blind test showing that very low jitter rates are
> audible, or to be able to point to an acceptable research document that
> shows a blind test (or other suitable scientific method) was done that
> proved or disproved that claim.
>
> That said, few who post on this forum (or I would wager, any hobby
> forum) will be equipped (or motivated) to do the research first-hand,
> so we're really left with locating publications to back up competing
> claims for or against. Dueling reference works - woohoo!
>
> Your second point is that the article I offered does not meet 'the
> criteria' for serious scientific research and might be discarded as
> self-serving marketing hype (which is also Pat's take on similar info).
>
>
> I hope I understand this correctly? By implication one could also
> conclude that since no scientific proof of jitter audibility has been
> presented to Pat his position is supported/proven? Hmmm...questionable,
> that one.
>
> (As a side note - did anyone bother to pay the $20 and read the AES
> article mentioned earlier in the thread which might provide scientific
> research that supports the audibility of low level jitter? No? Okay
> then, just checking)
>
> In my view, what we're really arguing is competing belief systems. If I
> understand correctly, you and Pat believe that only 'acceptable
> scientific research' yields valid answers in the real world. All else
> is snake oil or self-delusion. Science is the ultimate test of
> anything.
>
> That's fine as long as you realize your reliance on 'scientific proof'
> is a personal belief system. You believe in the scientific method (or
> maybe it's infallibility?).
>
> Unfortunately, science is remarkably fallible in the real world and
> even careful research can lead to all sorts of interesting outcomes.
> Take caffeine for example. Caffeine is bad for you. No wait, new study
> - caffeine is good for you. Oops, we did another study and it's only
> good in moderation. Well...which is it? (And was the pro-caffeine study
> paid for by Folger's Coffee?). Science is just as susceptible to
> commercial influence as any other human endeavor.
>
> To hold scientific research up as the only acceptable standard for
> right or wrong is...debatable.
>
> With the above in mind, I provided an example of an article providing a
> series of experiments and listening sessions that meet my criteria
> (belief system) for acceptable methodology. So you are more skeptical
> than I am and you reject the method and the conclusion. Fine.
>
> But that's your choice and you own it. If you choose to reject
> someone's example because it doesn't match your beliefs that's fine,
> but don't make it the other person's responsibility to support your
> beliefs. That's my bone with Pat. He's demanding other people toe the
> line and conform to his belief in science as the ultimate arbiter of
> what is valid and what is snake oil. Um...no thank you.
>
> It's okay to "believe" that for any test to be valid it must be blind.
> It may be wrapped in science but it's still a 'belief'. An opinion.
> Completely valid, but only to the holder of the belief.
>
> I think several posters on this thread were trying to make a similar
> point in their own ways. Everything is relative. There is no right or
> wrong, just better or worse. No time to argue with someone who's mind
> is already closed. They simply don't share Pat's belief system and
> didn't want to be pulled into defending their own. I don't blame them.
> Perhaps this is why Pat always gets so much pushback when he demands
> scientific proof? What he's really demanding is that everyone buys into
> his belief system. Not going to happen.
> Best regards,
>
> Pete
>
>
>
What I am getting from both sides is similar. Pat Farrell believes that
there must be some concrete number somehow that can act as a starting
point for understanding. i.e. Human hearing can detect 3db of variation
from flat response and 0.2db of variation from adjacent tones.
Something like that can be measured, established and then used as a
basis for further discussion.
What Pat (ar-t) is saying is that people have been shown to hear the
effect of jitter. It is a complex thing to describe because it is
frequency and distribution dependent, and that current techniques to
measure and describe it are inadequate. His long experience with RF
tell him that:
1. People are measuring the wrong thing
2. People are simplifying the description of value
3. Discussions to date are comparing apples to bananas
4. The design solutions are not widespread, are hard for a DIY
person or even real design teams to implement without
the right know how or test equipment.
My take is that based on widespread experience, jitter is clearly
audible. The effect of jitter is subtle compared to other distortions
like THD or TIMD. Pat (ar-t) characterizes that it is easier to hear it
by its absence than its presence.
It would be helpful if Pat (ar-t) could name a few names of designs that
have good low jitter implementations where it counts. A handfuly of
single clock CD players so that people could verify would be very
helpful. I understand our beloved Slim boxes have multiple oscillators,
so they are already not optimal for that reason even if the rest of the
design is good.
Since people on this list will not have the means to measure the jiter
and characterize it to conclude, the next best thing might be some
reference points of widely available equipment:
Try this CD player through this DAC and then the Slim through the same DAC.
Then the CD player alone (no SPDIF issues) and the Slim alone. One
would characterize the SPDIF capabilities of both platforms as things
the subjectivists could then attempt to describe in language terms. The
other would provide a well measured reference point against our Slim
platforms and let people draw subjective solutions from there.
If Pat (ar-t) gets around to developing mods, I am sure that many incl
myself would show interest. I do appreciate this discussion since my EE
background lets me do the armchair quarterback POV here. My day to day
is software, not signals and systems, but I remember enough to respect
the difficulty of the task at hand.
-MA
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