Generally, we separate the sound of the video for editing with specialized softwares. You will perhaps not often use external tools because such high-tech softwares require high musical skills for an effective implementation : everyone is not a sound engineer. In most cases, plugins integrated in Studio offer simple effects to implement. But in some cases, most commonly to remove a scratch or an incident of editing, you will use this technique to extract a WAV file from your video clip. In this case, refer to our tutorial :

[Rip the soundtrack of a video clip]