I am a bit unsure as to exactly how you have the tracks set up - can you give me a little more info?
I would like to know what tracks you have set up for this situation.
Did you set it up as a simple instrument track (audio and midi merged into a single track)?
If you have a separate midi track 'pointing' to the synth, are you meaning that the output selection for the midi track is set to drive the SD3 module?
Is there a separate audio track set up? If so, what do you have specified for Input for that track? (Should be SD3 - Primary Output:Stereo)
You indicate you hit play but there is no sound - what is trying to play? Is there midi data that is recorded on the SD3 midi track?
Do you have the 'Focus' on the midi track for SD3? Sonar will only produce sound for a synth if a midi track associated with that synth has Focus (meaning you have that track selected).
Please respond, so that I know how to explain things to you.
Thanks,
Bob Bone