When you use Download Surgeon's SC Recorder module on your Mac, SC Recorder
redirects the audio stream through a utility called Soundflower.  While the audio is
being routed through Soundflower you will hear no audio from your computer.  

Once you stop the SC Recorder, Download Surgeon will reset your Sound settings back
to what they were before using it, and you should once again be able to hear audio or sound
on your machine.