Extracting vocals from an already existing song

[RushMaster]

Anyone know if it's possible to extract vocals from an already existing music file?

[RushMaster]

And I'm talking about, extracting the vocals to just KEEP the vocal track and trash the rest.

[redwudz]

Not too likely. You might have more success with a 5.1 audio source where the vocals are usually on separate channels. With just stereo, it's near impossible to extract just the vocals with any reliability. If the vocal frequencies are the same as the rest of the audio, there's no way, AFAIK, to separate them completely. You may be able to filter out all but the vocal frequencies, but it likely won't sound too good.

[guns1inger]

Theoretically, this will work, however there are a couple of caveats

1. MP3 source is a no-no. Part of the way Mp3 compresses audio kills the stereo sound field, and the integrity of this field is vital for good removal of vocals (yes, I know you want to keep the vocals, but to do this, you first have to remove them)

2. You can only cleanly remove vocals from a stereo track if they are mixed equally in both channels. If they are not, you can't get them out. And anything else mixed evenly down both channels will come with them.

The theory behind vocal removal is simple. If you take one channel of a stereo file, invert the phase, and apply it to the other channel, anything that is identical will cancel itself out, and therefore disappear. On most recordings, the main vocals are mixed straight down the centre of the mix, so this theory works surprisingly well, some of the time.

Therefore, theoretically, if you can get a version of the audio that has the vocals removed (by removing them yourself), you should be able to invert the phase of this version, overlay it on the original, and remove everything but the vocals.

Step one can be automated - the AnalogX Vocal Remover is a nice, simple filter to do this and works iwth any audio software that uses DirectX filters.

Step two, overlaying the stripped version on the original, must be done manually.

Now, remember those caveats at the start of this post ? This is where caveat two usually bites you on the arse. Rarely is it only the vocals that are mixed straight down the centre. When you are removing vocals it usually doesn't matter if you lose a little percussion or take a little edge off the bass. However, if you just want the vocals, you will have a hard time getting nothing but.

Final note : this process only works if the original source is mixed in a manner that suits. There is no simple process that will just do this for any track. I have had to do this many times, and most of the time there is residual damage done because more gets pulled out that is desirable. Go in expecting it to fail, and you will pleasantly surprised if it works.

[AlanHK]

See http://audacityteam.org/wiki/index.php?title=Vocal_Removal
for methods of vocal removal (as Gunslinger says, that's the first step) with Audacity.

This is often done to make karaoke backing tracks.