As stated before it is near impossible to remove Vocals unless it is on separate Channels. I have noticed a lot of people wanted to hear a sample of the Vocal removal on Adobe Audition, And I noticed no one has done it. So I was messing around with Audition to see what I can do in terms of removing Vocals.
Here is "Hotel California
" without vocals or lead guitar, You can hear the voice faintly, but I am sure you would hardly notice it after you added the lead Guitar to it (your own that is)
This was done using Adobe Audition 1.5 and I used several filters.
1) Center Channel Extractor (Used that for the "Vocal Removal")
2) Channel Mixer (Used that for "Vocal Cut")
3) Hard Limiting (Used that for "Default Setting")