In the Eliminating the Lead Vocal tip, I talked about how you can remove the main vocal part from a prerecorded song to be left with only the backing tracks for karaoke and other purposes. Well, some of you have asked if you can also do the opposite. That is to remove the backing tracks and just be left with the lead vocal part. The answer again is yes and no.
Yes, you can extract the lead vocal from a prerecorded song, but only if the vocal is panned directly in the center of the stereo field. But as with eliminating the lead vocal, the process isn't perfect. There isn't currently any audio software on the market that can analyze and extract only a single part from a recording. Instead, you have to isolate the material in the middle of the stereo field. That means isolating the vocal and everything else centered in the mix.
Fortunately, Sound Forge has a special Mid-Side conversion feature (normally used for another purpose) that pretty much makes this process automatic. Without it, the process would be much more involved (ie. having to remove the vocal first, converting to mono, phase inverting, and recombining with a mono version of the original file).
Here's how to do it the easy way in Sound Forge:
1) Open the original audio file.
2) Choose Edit > Select All to select all the data in the file.
3) Choose Process > Pan/Expand.
4) In the Pan/Expand dialog box, choose the Normal Mix Of MS Recording preset.
5) Click OK.
6) Choose Edit > Selection > Set.
7) Choose Left in the Channel parameter drop-down list.
8) Click OK.
9) Choose Edit > Copy.
10) Choose Edit > Paste Special > Paste To New.
11) Save your new audio file.
Depending on the type of material that you're processing, the results will vary, but they'll never be perfect. Anything that was in the middle of the mix will now be in your new audio file, which probably includes the vocal, bass, and some of the other background instruments. You can try to tweak the mix a bit with EQ, but other than that, what you get is what you get. Maybe in the future we'll have more sophisticated software available that will be able to analyze and separate specific sounds from an audio mix.
For more information: Sony Sound Forge Audio Editing Instruction Books
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