Hi rharv and many thanks for your speedy reply. In response to your questions:

In prefs-midi devices what is selected in the output device column? EDIROL UA-25 (my external USB sound card/midi-audio interface)

Is there a check in the box 'reroute MIDI to DXi synth' box? YES

What synth is being used in the default DXi synth slot just below? <VSTi> Super Quartet

Any ideas?

Mark