I'm adding a synthesizer line to a recording I'm working with. I've gotten a nice sound using Ableton's Operator FM synthesizer, and I'd like to add some vibrato to it. Generally, this is done by using an LFO tied to oscillator pitch, and varying the intensity of it over time.

The problem I've run into is that Operator only has one LFO, and I've already used it as part of the design of the sound. It's not available for pitch modulation.

Is there another way that I can achieve this vibrato sound, perhaps in post production? It doesn't need to be played realtime, I just need to get a finished recording.

I'm using Ableton Live as my recording environment, but solutions using other tools are certainly welcome.


It should be a fairly straightforward DSP effect, if you're happy to do it in the mixdown. Some chorus and rotating speaker effects can also be wound back until they're just vibrato.

  • I did end up using a DSP effect in a pinch, when I remembered that Live has a Frequency Shifter device with a built-in LFO. It works for now but I'm not completely happy with the result, so I want to try the other ideas too and see how they sound. – Warrior Bob Nov 29 '11 at 15:11

There are also MIDI LFO plugins which you could link to your instrument's pitch. Can't really think of any off the top of my head since I've never had the need to use them, but some googling will probably find you a good one.

  • This is a great idea. Someone also suggested the Max4Live device LFOEverything to do conceptually the same thing (although I don't personally have M4L). – Warrior Bob Nov 29 '11 at 15:21

I would have thought the Auto Filter would be a great choice for this. I use it for wobbly basslines and leads all the time and it has it's own LFO.

  • Auto Filter is a filter - it doesn't modulate pitch at all. That LFO just modulates the filter parameters (cutoff frequency, I believe). It's a great effect, but doesn't help in this particular scenario. – Warrior Bob Aug 30 '12 at 17:31

Check out the free SOUNDOR synth from Percussa, it's also an FM synth like Operator, but it has more complex modulation possibilities.

Also, you might be interested in IMPROVISOR, which is a free app that works standalone and can send MIDI to any hardware or software device, and which is capable of generating complex LFOs based on waveforms you can draw yourself.

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