Hi

Look up Pitch shift in the user manual.

For example, to create the Doppler effect you need to ramp (envelope) the pitch starting at eg 1 octave above normal through normal to 1 octave below.

How fast this occurs depends on the sound length - you may also have to stretch the sound length and adjust for the initial pitch shift first before applying the ramped pitch effect if the sound clip is too short.

To give a more realistic effect also pan the sound from one channel to the other eg have the sound in the left channel only and pan to the right channel only, or vice versa, over the same length as the sound object.

HTH

John EB