Re: Envelopes: Think of the initial cutoff value as an offset. If you have a positive ENV Amount, it gets “added” to the initial cutoff value (much like moving the cutoff knob clockwise at the envelope’s rate). The inverse goes for a negative ENV amount - it subtracts from the initial value (i.e. it moves the cutoff knob counter clockwise).
Experiment here: on the A4 AMP page, set VOL to 0, A=0, DEC=INF, S= Max, R=Inf. Press a key - nothing is heard. Go in your ENVF page and set DEST to AMP VOL fully clockwise - now the ENVF controls your voice volume. Much like on an SH101 where you only have one envelope to control filter cutoff and (VCA) volume…
Sync: here is an awesome description of oscillator sync matters… http://www.cim.mcgill.ca/~clark/nordmodularbook/nm_oscillator.html