SV: [sdiy] sawtooth phase shifter

[karl dalen]

--- harrybissell <harrybissell at prodigy.net> skrev:

> My project for the week is a sawtooth phase shifter...
> more like a waveform animator.  It has three stages,
> each driven from a Schmitz (tm) three phase VCO.
> 
> It sums the shifted sawtooths, the pulses that form them.
> You can pan between pulse and saw.
> 
> I'm driving it from the "muffy" guitar synthesizer.  It has
> sawtooth outputs at F and 1/2 F ~or~ 2F.
> 
> Sounds... how can I put this delicately ... underwhelming.
> Like the 'hex fuzz' the more stages you sum, the more
> subtle the effect.
> 
> One neat thing... If you enable both F and 1/2F ~or~
> F and 2F at the same time (now there is a sum going into
> the phase shifter)... you get a pronounced "fifth" sound.
> This is extremely cool... as this is generated from the
> direct 'waves' output of the guitar synth (so there is no
> VCO involved ie, no delay... and you get a tracking fifth).
> 
> I have yet to re-simulate this and see where the fifth is
> comming from.

>From summation of waves, (additive).

> 
> One possible enhancement I'm thinking of is to make
> a sawtooth wave at 1/2F, F, and 2F simultaneously...then
> shift each one separatly. If you use a single wave, the
> phase shift should approximate FM (vibrato).  With multiple
> waves... I have no idea.  I sure hope its more 'whelming'.

Its not, i have tried it (if we are talking about
 the same thing offcourse) FM, yes, you will get
that but as F increases the FM effect weeakens out,
at high F you dont hear it at all!

I had also hoped that it would have achived
FM without changing F, but this is small
phase change in a time domain! Ah, well, 
lets say that you could rotate phase futher,
several tousand degrees as you increase F,..... then!

Reg
KD