Be sure you make the right patch so you can hear your synthesizer.

You'll need to use two different patch cords located on the back of the studio door:

There are two kinds of patch cords located in this picture:

1) 1/4 inch TRS (the larger ones) which are used for the synth patch bay

2) tt (= tiny telephone) for the main patch bay.

You'll want to make this patch:

Synth Patch Bay: Proteus 1 out -> Tie line 1

Main Patch Bay: Tie Line 1 out -> Mixer line input #1

PATCH Tie 1 out (red, or right side) into Line input 1....at the top left of this patch bay (not seen in this shot)