how would i simulate "phase offset modulation" as found in Reason's Subtractor?

hello, i want to simulate phase offset modulation using reaktor. i will copy a short bit out of the reason help to tell you what it is if you dont already know


"When phase offset modulation is activated, the oscillator creates a second waveform of the same shape and offsets it by the amount set with the Phase knob. Depending on the selected mode, Subtractor then either subtracts or multiplies the two waveforms with each other. The resulting waveforms can be seen in the illustration below."

so basically it can turn a saw wave into a square wave with PWM by subtracting a saw wave from a saw wave and modulating the delay time of one of them

i have no problem subtracting the saw wave from the saw wave, thats easy. the problem is translating the length of the saw wave into MS and feeding it into the single delay module.

to accomplish this i have tried a few things, but the best idea ive had so far was to have a thin (.98) square wave oscillator run at the same pitch as the saw wave and run it through the A to E module then into the Timer module. the timer module is supposed to time the increments between each event and send off the number in MS or HZ. i sent the MS output into the delay time and thought i was a genius, but it didnt work. it did turn the saw into a pulse wave of sorts, but the length of the pulse wave was not consistant across the whole keyboard


please help me to figure this one out


thanks in advance
johnG

 

simply calculate 1/f where f = frequency of saw-osc, because: 1/t = f and t = 1/f. the value you get is in s, so multiply it by 1000 to get ms. convert the oscs pitch to a "real" frequency before, using the exp-module.
btw.: don´t use a single-delay or you´ll get clicks in the output. better use a mod-delay.

regards

max/welletnal

 

alternatively

see pic

 

triptonizer, you ROCK.

The phase offset modulation in Subtractor was the whole reason I got in to Reaktor (wanted the same feature on other synths, which never had it).

THANK YOU!

-Alex

 

Phase goes from -1 to 1, yeah?

-Paws

 

thanks, im about to go boot up the old powerbook and try this.

phase offset can make some really good sounds. nothing extremely out there, but i use it for some funky basses


thanks again
john

 

Phase between 1 and zero will give you pulses between 50% and +/-100%, between -1 and zero -> 50...0%; if you subtract the syncing osc from the synced one it's the other way round (positive phase -> neg width).

 

hey triptonizer, i did your setup and it worked very well for both subtracting and multiplying saw waves just like in subtractor, thanks....

but, the same setup does not seem to work for square waves. when i subtract i get a plain square wave when i should be getting some kind of mutation of a square wave, and when i multiply i get no sound whatsoever.

i didnt realize this, but multiplying square waves is actually pretty important to the usefulness of this synth for me. could you please help me out one more time?


thanks
john

 

ok disregard my last post, i stupidly forgot to attach the gate =)


i did notice that the effect was a bit different from reason and there was little to no effect in either subtract or multiply except for in between .9 and 1. so i made that the knob range and added an event smoother and i think it might work out



thanks again!
john