[sdiy] Wavetable lengts during scan!

[Harry Bissell Jr]

Not exactly so...

One of the address inputs does this but the
other select ~can~ cause glitches

I figured out that you might add a small
amount of hysteresis by taking the 4 bit select,
using a D/A converter on them... and feed back a
portion into the input to the A/D converter.

(not built but tested in simulation OK)

You could do this digitally as well (but it
is not easy)

Or with a PIC (which might be easy but not super
fast)

This can be a problem if you sweep the waves with a
very slow source (LFO or ENV GEN)

Still... its a very cool toy

H^) harry

--- mark verbos <mverbos at earthlink.net> wrote:

> the Wiard Miniwave has a zero crossing detector so
> there are no clicks 
> when using it as a wavetable oscillator.
> 
> Mark
> 
> 
> 
> 
> Paul Maddox wrote:
> > Karl,
> > 
> >> I wonder how long should a wavetable be to avoid
> >> the *gritting/grinding/stepping sound during
> adress
> >> scan trough the table?
> >>
> >> Im not talking about * jumps between complete
> waves
> >> as a method of scan, and there is no
> interpolation possible.
> >>
> >> The length i have at the moment is 127 stepps and
> its
> >> grinding.
> > 
> > 
> > I use 256 samples per wave on the monowave,
> ideally I'd go for 1024, but 
> > that takes a lot of space and *very* fast main
> oscillator :-)
> > 
> > When it comes to 'scnaning' through a table,
> > I'd use tables with lots of waves (I'd say 255
> waves as a minimum)
> > and make sure you *ONLY* switch to the next wave
> at the zero crossing 
> > point (Waldorf Wave is the only wavetable synth
> I've heard that does 
> > this, and the effect when moving through a table
> is a *lot* smoother).
> > 
> > Paul
> > 
>