volt control of osc triange tilt?

Fraser, Colin J Colin.Fraser at scottishpower.plc.uk
Wed Nov 10 11:05:45 CET 1999

> -----Original Message-----
> From: WeAreAs1 at aol.com [mailto:WeAreAs1 at aol.com]
> Sent: 09 November 1999 20:19
> To: Fraser, Colin J; synth-diy at mailhost.bpa.nl
> Subject: Re: RE: RE: volt control of osc triange tilt?
> Actually - yes, it would sound the same, that is, if you are 
> using the 
> oscillator as an audio oscillator.  But if you are using it as an LFO 
> waveform (as I suspect Paul Perry wants to do), then the tilt 
> direction 
> becomes quite significant.

Indeed, but the 3396 oscs can't be used as LFOs, so that's OK for Matrix 6
It may make filter FM sound different I guess - I've never actually tried
filter FM by audio osc with tilt mod.
Need to have a go...

> << Would applying a rectified modulation waveform to a vco with 
> only unipolar modulation of tilt sound the same as applying the same 
> modulation waveform, unrectified, to a bipolar tilt input ?
> Would this also apply to PWM ? >>
> I'm afraid I don't understand this.  Maybe I need another cup 
> of coffee to 
> kick-start my brain.  Could you explain further?

Since a 40% pulse wave has the same harmonic content as a 60%, 30% as 70%
and so on, if you modulate the pulse width with a triangle wave from 50% to
80% (ie the rectified modulation), will it sound the same as a pulse wave
modulated from 20% to 80% at half the modulation frequency (ie the
unrectified modulation) ?
If it does sound the same on it's own, will it interact differently with
other waves ?

If only the ceiling in my studio hadn't caved in (fortunately after I got
all my gear out), and insurance companies worked on non-geological
timescales, I could go experiment :-(

Colin f


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