damianadams I'm assuming you are using Mobius 3. You can "pass through" the sound source by going to the Sessions menu, then the Globals Tab selecting Miscellany from the left hand menu tree and then clicking in the empty box to the right of "Monitor Audio". This will pass through the sound all the time, not just when the selected loop is empty. If what you are after is to only monitor the audio when you first record on an empty track, you might be able to do that via a script but I'm not sure.