drum tracks

i am pretty sure that removing drum tracks from most songs is possible without the certain frequencies
but is there a way for me to identify and pinpoint them easier?
also would it be possible to reduce the output of the center pan, rather than mute it entirely? so i can keep the vocals (albeit softer) with the drum tracks still evident?

I don’t think you’ll ever be able to remove drums from a song unless you have an exact copy of the original drum track that you can use to subtract from the original. When I say ‘exact,’ I mean it. It would have to be from the original studio recording session or a copy of the drum machine program. The original track would also have to be unprocessed and that’s really unlikely. At present, for all practical purposes, it’s impossible.

As for the bit about the Center Pan Remover, I assume you’re talking about the one written by David R. Sky (the dialog box when you open the effect mentions his name). Unfortunately he’s on an indefinite hiatus from audio development or you’d be able to email him and ask. He’s a very nice guy. Sadly, I know of no way to do what you’re asking with that plugin since it seems to throw all the other frequencies out of phase (admittedly I’ve only done a small amount of testing). There may be other center pan remover plugins out there that allow you to adjust the level of reduction, but I can’t think of any. They may also be called “Vocal removers” or “Karaoke” plugins as well. Those all seem to do roughly the same thing.

Yes, it’s quite easy, although it is not usually necessary as the center-pan removal usually leaves a fair bit of vocal anyway (due to reverb, and any other off centre vocal sound.

So how centre pan remover works:
You have two audio channels, one is the left channel, and one is the right channel.
Anything that is panned dead centre will be identical on both left and right channels.
By turning one channel “upside down” (inverting it) and adding it (mixing it) to the other channel, the result will be the difference between the two channels.
The difference between two identical signals (anything that is dead centre of the stereo mix) is nothing (silence).

How to do this manually (Audacity 1.3.5):
With a stereo track -

  1. Click on the little black triangle next to the track name for the drop down menu.
  2. Select “Split stereo track”
  3. Select one of the tracks and SHIFT+M and select “Mono”
  4. Select the other track and SHIFT+M and select “Mono”
  5. Make sure that one of the tracks is selected and from the Effects menu select “Invert”
  6. Ctrl+A to select all
  7. From the Tracks menu, select “Mix and Render”

How to reduce, but still leave some of the centre pan audio:
Just like the above method, but we do not want the centre pan audio on our two tracks to match exactly, so we create a small difference between them. The greater the difference, the more will be left in our final mix.
After step 5) select “Amplify” from the effects menu and set the amount to a little less than zero.
(how much les than zero, depends on how much you want to leave. If you slide it all the way to -50dB, you will basically just get the other channel after the mix.