Ableton Operator is a small FM synth which comes with Ableton Live Suite. Operator may seem limited to familiar traditional FM sounds but it is capable of much more. Here I show thirteen advanced tips and a few ways to use Operator’s lesser known features to create bigger sounds. and a few you might not expect, ranging from deep rumbly analog-style basses, evolving leads and pads.
1: Make oscillators morph from sine to “sawtooth”
The oscillators can be set in various FM modulator / carrier routings, but if an oscillator has no modulator input then the oscillator feedback parameter becomes available. Setting an oscillator waveform to sinewave and turning up the feedback parameter will feed the sine wave pitch back on itself and you will hear the sine morph into a waveform which sounds and looks quite similar to a sawtooth.
This waveshaping effect is is dependent on the oscillator amplitude (as amplitude induces feedback), so turning the oscillator up will take the waveshape closer to a “Saw”, turning it even higher will make it distort toward noise, and turning the amplitude right down will take the waveshape closer to the original sine.
The oscillator amplitude is obviously affected by its (amplitude) envelope and by all the other modulation sources mapped to oscillator amplitude – LFO, Aux envelope, modwheel, after touch, etc. meaning you now have deep control over the waveshape of these oscillators.
Of course – morphing a sawtooth wave into a sine wave is very similar to what a lowpass filter does it removes high harmonics – but the benefit here is that each of the four oscillators can independently vary from saw to sine, as if you had 4 independent filters (or 5 if you count the filter itself !). Additionally the smooth interaction between volume and waveshape gives a good almost natural physical modelling feel to the waveform. It’s a unique sound.
2: Invert harmonics for hard to reach waveshapes (a Triangle wave)
Operator has a very handy method of drawing your own waveshape with partials and you will be able to get clues for how common waveforms look as harmonics by studying the built in waves. Not all waveshapes are possible with the basic approach. The reason for this is that harmonics also have a phase relationship, a fundamental might be oscillating up while the third partial is oscillating downwards (180 degrees out of phase). This is the case with the humble Triangle wave.
The basic additive waveform drawing system of Operator does not allow for drawing harmonic phase relationships but we can emulate out of phase partials by using a second oscillator with a waveform phase offset. 50% of offset is 180 degrees of phase difference.
A triangle wave contains the same odd numbered partials as a square wave – yet is plainly very different in sound. In a triangle wave the phase of the upper partials is 180 degrees out of phase with the fundamental. You can see in this image that Oscillator A is handling one group of harmonics (1,5,9,…) and the second oscillator (B) is taking care of the harmonics which are inverted. Combining these two oscillators together allows us to create a waveform with harmonics with relationships which are out of phase with each other. In this case we make a Triangle wave, but the same principle allows other (otherwise unavailable) waves.
Notice that PHASE INVERSION on the B oscillator which is what makes our complex triangle output.
Triangle / Square wave morph
In the above GIF we can see what happens if we make oscillator D a copy of oscillator B but turn in Oscillator D make sure to reset the phase parameter of that oscillator down to 0, and then by using the LFO to crossfade between these two variations (B and D) the wave changes between a triangle and a “square”. the same principle can be used to create more complex harmonic shifting effects. See tip 5 for more on this.
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