For pitch-based ‘laser’ sweeps we switch off the noise source and engage the synth’s conventional oscillators. Let’s start with a sine wave. We’ll use Logic’s ES-2 plugin to show how the same principles apply in a different subtractive synth.
This time, we’re going to disable the filter and use the second envelope to control pitch – this is usually done in a synth’s modulation section.
Using a slow attack we get a rising pitch sweep:
Things get a little more interesting when we throw in an LFO. This is also going to modulate the pitch, but this time to provide an extreme vibrato effect:
We can also modulate the LFO rate so that the vibrato gets faster as the pitch gets higher. This is where a comprehensive modulation section can really come in handy.
Changing the original oscillator waveform can also have a significant effect:
There’s also nothing stopping you combining these ideas across multiple oscillators and a whole series of modulation routings within one synth patch. Here’s how it sounds with a noise sweep combined with two oscillator sweeps: