Polysynth: How do I use an envelope to control an LFO's rate (fade in the vibrato)?

[digaldeman]

I'm trying to create sounds with vibrato but I'd like to offset/fade in the vibrato. How do I use an envelope to control an LFO's rate in Polysynth or Sampler?

Also, is it possible to add vibrato to a Polysynth preset that already uses all 3 of Polysynth's LFOs (LFO1, LFO2, PLFO)?

[Kenit]

You can modulate the Depth of PLFO by the FEG and AEG.

[digaldeman]

You can modulate the Depth of PLFO by the FEG and AEG.

Thanks. I also got it to work by using the LFO Mod device.