How to remove music track from TV audio?

Hello all,

I’m currently working on a project that requires me to extract spoken lines from the original Star Trek show. TOS was originally broadcast with monaural sound, but I’m working with a 5.1 remastered version ripped from the 2006 DVD. I’ve listened to each of the tracks in isolation and determined that almost all the audio, including all the dialogue and most of the music and sound effects, is mixed into the center channel. The left and right channels (and, it seems, the back left and back right) contain music and sound effects, which as far as I can tell duplicate what’s on the center channel.

What I’d like to do is use the L/R channels as a reference to tell Audacity what to remove from the center channel, in order to isolate the actors and significantly dampen the music (and sound effects if possible though this is less important). I have tried mixing the L/R channels together, inverting, and then mixing the resulting track with the center channel, but all this did was make the audio tinny and horrible. Any suggestions on how to make this work, or is this task beyond Audacity’s capabilities? I’m open to installing plugins if need be. [Bones] I’m a biologist, not a sound engineer [/Bones] so I may be missing something obvious to you.

I’m running Audacity 2.1.3 on OS 10.12.4.


Kirk Butler

I’m not very hopeful. My guess is that the “surround sound” on the DVD has been synthesized from the original mono audio, so it is probably phase shifted from the centre channel and so normal “cancellation” methods won’t work. If this is the case, then I’d expect the results to sound tinny and horrible, which is what you go on to describe.

There’s a discussion about other tools / techniques that may be helpful in this topic: but I’m not optimistic.