[sdiy] Delayed LFO fade-in time

[Richie Burnett]

When programming LFO delay to implement delayed vibrato is there any 
convention as to how the "fade-in" time is determined?

For instance, I know that if the LFO delay is set to zero then there is no 
delay and pitch modulation occurs immediately at full depth on all synths 
I've tried.  However, if I select some LFO delay, then there is no pitch 
modulation for some time, and then it is introduced *gradually*.  Should the 
"fade-in" time for the pitch modulation be proportional to the delay time? 
Or maybe it should always be a fixed amount of time?  ...or maybe even a 
fixed number of LFO cycles at whatever the LFO rate is?

Also, I believe that LFO delay should only work on pitch modulation of the 
VCO, and not actually delay the introduction of VCF modulation or 
pulse-width modulation?  Is this other people's understanding too?

For a polysynth LFO delay will be polyphonic?  So that's one LFO oscillator 
to implement in-phase vibrato across all voices, but 8 separate mono-stable 
timers for the LFO delays in an 8 voice synth?

Many thanks,

-Richie,