Hi Milhouse,
As dobro said you can't just remove the vocals and leave everything else in tact, but you can come close enough if all you are thinking about is a poor man's karaoke.
The following conditions must apply for you to remove vocals:
The track must be stereo
The vocals must sit in the middle of the stereo mix (not towards the left or right). - There is a way around this as well, but it's a bit of work.
Open your stereo track and mark the entire track (ctrl A). The go to Transform/Amplitude/Channel Mixer. There should be a preset named "Vocal Cut". If you don't have this preset then use the following setting:
NEW LEFT CHANNEL
L 100
R -100
Invert don't tick
NEW RIGHT CHANNEL
L -100
R 100
Invert tick
You could also try reversing all settings (change the 100's to -100's and vice versa and the inverts)
It would be a good idea to save these settings as a preset.
All you are really doing is inverting one channel (changing the phase by 180 degrees) and mixing (adding) both channels together. You end up with two mono channels with the same signal on both channels and you can then create a psuedo-stereo effect (but that's another story).
With other wave form editors all you have to do is invert one of the channels and create a mono mix from the stereo mix (this removes the vocals) and the create a new stereo mix from the mono mix (this gives you two tracks in which to create a stereo effect).
The main disadvantage of cutting vocals with this method is that any other sound or instrument occupying the same, or close to the same position in the stereo field is also lost or heavily attenuated.
What happens if the vocals have not been completely cut or you notice that the vocals are positioned left or right in the original stereo track?
At the risk of making this answer a little long-winded: you have to amplify or cut the level of just one of the stereo channels in order to "move the vocals to the middle of the stereo field. For loud music decreasing the level of the louder track, for quiet music amplifying the quieter track works best.
To save a lot of time, find a passage of your song (about 5 sec) where the vocals predominate and save this small passage as a test piece to work on. As an example- I have my test piece of rock music where the vocals are sitting slightly to the left in my stereo field (use headphones!!). I mark the left channel and apply amplification of -1dB on hearing the results, the vocals have "moved" to the right but are not exactly in the centre. Undoing the last change (this is easiest method), I then apply -2dB of amplification, but the vocals have moved too far to the right. Undoing again, I apply -1.5dB of amplification, listen and so on until the vocals are sitting in the middle. I then note how much amplification I used to get my vocals centred in my test piece, going back to my original song, I mark the whole of the left channel and apply the same amount of amplification as I did in my test piece and then continue with the vocal cut process.
Again, just to stress that by using these methods to cut vocals you will also affect the rest of the track - you can't just change the vocals and not affect the rest of the instruments, but with some imaginative EQing you can get some pretty good results.
I hope this has been of some help.
Regards,
John