If you select the synced square and sawtooth waveforms for oscillators 2 and 3, they are synchronized with oscillator 1. In the Sync Start setting, only oscillator 2 is audible, and oscillator 3 is switched off.
Typical sync sounds feature dynamic frequency sweeps over wide frequency ranges. These frequency modulations (the sweeps) can be applied in various ways.
Do the following:
Try the pre-programmed pitch modulation, assigned to the modulation wheel first.
In the second router channel, an envelope pitch modulation has been preprogrammed (target = Pitch 2, Source = Env 1). Setting the minimum value to 1.0 results in a typical sync envelope. Also check out shorter Decay Times for Envelope 1.
To avoid a sterile, lifeless sound (after the decay phase of the envelope), you may also want to modulate the oscillator frequency with an LFO. Use the third router channel, and set the minimum modulation applied by LFO 1 to about 0.50.
Substitute the synchronized square wave with the synced sawtooth wave, and see if you like the results.
Note: Pulse width modulation is also available via the synchronized square wave of oscillators 2 and 3. A modulation of the wave parameters of these two oscillators results in a PWM when the synced square wave is selected.