Show Cue System

I need to play a pre-recorded commentary over a backing track of police sirens and helicopters. For this to work, when the commentary is started, I need the background to fade down to about half, then back up when it is finished.

I have tried mixing the two files together in Audacity, fading the background down and up, but the timing doesn't always work as the actor has to walk across the stage and turn the TV on (where the commentary has to come from); it looks really bad if the commentary starts before he reaches the TV set.

Is there any way I can achieve this in SCS?

One way is to have the backing track as Q1 and the commentary as Q2. Add a Level Change sub-cue to Q2, that fades Q1 and starts at the same time as Q2 (or later if you prefer - you can tweak the settings). Add a further Level Change cue as Q3 to restore the level. This can either be manually activated or auto-started at the end of Q2 (or a certain time after the beginning of Q2). Having the files as two separate cues means that they can be sent to two different devices (speakers) if you have them.