[sdiy] Truly white noise

[Robotboy8 at aol.com]

In light of recent threads I have a few general observations about white 
noise.  They might be wrong - in which case I'm sure I'll be corrected - and a few 
of these points are probably common knowledge, but I feel that some on here 
need reminding.

*Most people only need something that sounds like white noise.  For instance, 
a detuned radio.  No, it isn't white, but it sounds good enough to mix with a 
VCO before filtering.

*White noise is only necessary (truly white, I mean) for testing, scopes, 
etc.  Most other applications - well, see above.

*Obtaining truly white noise is difficult because most components 
(amplifying, etc) will color the spectrum.

*To get truly white noise, why don't we just build massive amounts of 
sinewave oscillators, record them all tuned hundredths of a cent off and phased 
slightly off from one another, then layer that recording over them all tuned an 
increment higher until we have literally every frequency we can generate?

*Would this truly white noise not be loopable at whatever smallest number 
ratio all oscillators have in common?

*Truly white noise would have to be scalable - containing all frequencies in 
the same amplitude, such that if you pitchshifted it up some it would still be 
white, because all frequencies a human can hear are still present (those that 
were subaudible or above audible before are now shifted into audible range as 
others are shifted out).

Am I right in these?  Just trying to place myself and help anyone else, not 
to mention spark some interesting conversation.

       -eric
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