[sdiy] preferred noise source circuits

[Tom Wiltshire]

Well, if we're talking about "white" noise, then I mean noise that is  
genuinely white - i.e. has an equal distribution of energy across all  
the frequencies of interest (the audio band in our case). That's not  
really subjective at all. Likewise if you're generating random pulses  
or gates, then "better quality" means statistically indistinguishable  
from random. You don't want any unwanted weighting creeping in unless  
you put it there.

Obviously whether white noise is the best kind for many synthesis  
purposes is a much more subjective issue. Perhaps a 6dB rolloff of  
the high end makes a better audio noise source since it doesn't sound  
so harsh. If you've got good quality white noise to start with, then  
you can choose what you do to it. If it's got it's own flavour  
already, it's much harder to remove that.

T.



On 23 Jun 2009, at 12:38, Amos wrote:

> On Tue, Jun 23, 2009 at 6:09 AM, Tom Wiltshire  
> <tom at electricdruid.net> wrote:
> "a digital noise source with a simple 8-pin DIP microprocessor that  
> will give you much better noise quality than most analogue noise  
> sources."
>
> see now, I don't mean to stir the pot, but "much better noise  
> quality" seems pretty subjective to me.  This is what it (ought to,  
> IMO) come down to when choosing your noise source.  What qualities  
> do you evaluate when determining "goodness" of noise?
> This is more an open question for anyone who has an opinion on such  
> things.
>