[time-nuts] Clocks for Audio gear

Heinzmann, Stefan (ALC NetworX GmbH) Stefan.Heinzmann at alcnetworx.de
Thu May 10 17:25:33 UTC 2012


Chris Albertson wrote:
> If we are to believe the above paper,then those guys who claim to hear
> pS jitter are wrong.

Note that the jitter spectrum matters for its audibility. Ashihara et.al. used random jitter, and it is not very suprising that the sensitivity for random jitter is lower than for jitter that has specially been shaped to improve detectability by human ears. Thus the results by Ashihara are credible, but they are not the lower limit on jitter audibility.

Benjamin and Gannon, the first reference in Ashihara's paper, come to lower figures for sinusoidal jitter with carefully selected frequencies relative to the main signal, which is also sinusoidal. Their results reach down to the single figure nanosecond range, and that can be regarded as the real limit of audibility.

Of course, that still leaves those who claim to hear jitter in the picoseconds range out in fairy-tale land. And jitter of just a few nanoseconds is still quite easy to achieve with crystal oscillators. No need for special and expensive parts, then. Normal developer diligence is enough.

Cheers
Stefan





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