Well. I have partially succeeded in removing instrumentals from a song. But base drums ("bock" sound), snare drum ("tick" sound), violins, and a Synth Instrument sound remnants are still there (they are barely audible). I only want the vocals and no base drums and snare drums. Can anyone help me? I would be delighted to know the frequencies of the base drums and snare drums.

You can't really. Because the original audio was compressed into a .mp3/.wma/whatever audio file, everything is mushed together.

Imagine two pieces of bread, one with peanut butter and one with jelly (uncompressed original file). Now put those two pieces together (compressed .mp3). Now take the bread off and try to get all of the peanut butter off (what you're trying to do). You can't.

It might help in your search if you used a correct term, also. What you're talking about are acapella versions, and some popular songs have them already made. I'm not sure if there's a tutorial kn making your own though. The best amateur produces acapella version I heard was good, but you could still hear the music if you listened for it. If you get it to there, then I think it'll serve your purpose.

Yes I heard of it before. But I am trying to get vocals from a song that doesn't have an acapella version. I removed most of the instruments by using two tracks, one is the original with vocal and the other one is the off-vocal. So all I had to do is to match up the tracks to the nearest .00005 seconds and invert the off-vocal version. But you can still hear faint traces of the instruments (mostly the peaks).
*Edit* Here is the project: Download
The English Song Title is "Yuki, Muon, Madobe Nite." by Chihara Minori.