[sdiy] oscillator jitter / phase noise

[René Schmitz]

Hi Dave and List,

> True enough, listening is important (well duh, it's only the whole
> point of the thing :-), but you have to be careful about making
> statements like this because, taken to its conclusion, it leads to
> subjectivism.  Next thing you know, you're taking green Sharpies to
> all of your CDs.

Thats why I proposed a double blind test.

> Lab equipment tells us *why* one thing sounds better or different
> than something else, so that next time we know how to do it better.
> 
Before you can do that with lab equipement, you have to correlate a 
perceived difference to a measured quantity.

First you have to check wether there is actually a difference, and after
that you can try to find out what causes it.

If one would judge only with "objective" measurements, ignoring your
knowledge, there is no way of knowing if for example a high THD is
desireable, or a low one. Both are per se just numbers. Which have to be
interpreted to make any sense.

THD is a good example for a different reason, 5% of one type of
distortion may sound better, than 3% generated by another process.
Solely based on the figures, you would pick the worse.
Its easy to fool yourself into an objectivity that doesn't exist.

> It also exposes charlatans and eliminates personal biases.  We've all
> seen reports of "golden ears" that couldn't distinguish between their
>  pet $4000 mega-monster speaker wires and a set of battery jumper
> cables in a blind A/B test.  Subjectivism has been a blot on high-end
> audio for two decades now; let's not let it mess up electronic music.
> 
Sure, perception is always subjective. And often the money you spend,
your expectations, the work you put into something, or the knowledge
about the internal workings does affect the way you perceive something.

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159