zipper noise was: digital control

[harrybissell at prodigy.net]

Yes... you can put a "glide circuit" or lowpass filter on the DAC output. The trouble is... what rate to filter at. If you do a very slow (manual) filter sweep... you need a very long time constant. If you "whip" the dial quickly... the long sweep will fight you.

You could detect how fast the dial is moving and filter slow or fast (either digital of analog) or have so many bits and clock so fast that no-one can hear it.

The Studio Electronics AT1 (???) the "tone chamelion" model with the single "Alpha Dial" is the only hybrid synth I have ever heard that does not have zipper noise... Even at high resonance settings it is dead smooth. I'd consider buying it just for that reason. I wonder how they did it ???
:^) Harry


 ---- On Jan 11 DCMagnuson at aol.com wrote: 
> In a message dated 1/11/00 9:36:41 PM Eastern Standard Time, 
> harrybissell at prodigy.net writes:
> 
> > The other problem is "zipper" or step noise... when you move a value 
> through 
> > a
> >  linear range (especially an oscillator or filter sweep) you hear jumps in 
> > the
> >  audio (like a zipper...)
> >  Really good programming chops can cover most of this up...
> >  
> 
> Here's a question... I haven't ever built a glide circuit, so I haven't been 
> able to try this yet, but if you put a glide circuit on your DAC output, 
> would it cover up the zipper noise?  I was figuring this would work well in 
> non-critical situations (like a filter sweep)
> 
> Dave Magnuson
> Independent Music Site
> http://www.indiemusicsite.com