preenfm Forum

PreenFM => preenfm2 and preenfm3 => Topic started by: widdly on August 29, 2014, 10:22:37 AM

Title: Pulse Width Modulation on PreenFM2
Post by: widdly on August 29, 2014, 10:22:37 AM

Here's a trick for getting some nice PWM from an operator pair on the PreenFM2. 

The trick requires a pair of operators so use something like algo12.  Turn off all the IM, v and Mix except set Mix1 to 1.00 and IM1 to 4.08

Set Op1 to a Square Wave, keyb Freq 1.  Set a no attack, full sustain envelope while you test it out.

Set Op2 to a saw, keyb Freq 1.  Again, set a no attack, full sustain envelope.

Now go to the LFO page and set LFO 1 Sin  Freq=0.46  Bias=0.5

In the matrix page make sure all 12 Srce are set to none.  Then set Matrix 1 Srce to lfo1 Mult=0.9 Dest=IM1

You should have a PWM oscillator sound.  LFO1 controls the PWM speed.  The amount of IM1 is a bit tricky.  If you use too much you get an octave up effect happening.

I've attached a string sound I made using this trick.  I used 3 detuned PWM pairs.  The filter is mapped to the mod wheel.

Title: Re: Pulse Width Modulation on PreenFM2
Post by: Xavier on September 01, 2014, 11:34:36 PM

Thanks for this sound and explaination.
Sounds good, very soft !

Xavier