music software

Yes, it can. In GarageBand, that is.

 

Okay, you have your tracks and all that jazz, yes? By the track name furthest to the right, there is a downward facing triangle. Click it to bring up (down, rather) a line graph showing track volume. create points on the line by clicking, and then drag the points up and down throughout the song where you want a specific track to be louder or softer, respectively.

 

You mean can you isolate a single instrument from a pre-recorded piece of music? Say from an MP3? That's somewhere between difficult and impossible. The recording is not separated like that: all the instruments are sampled together. You could to it perfectly with the masters...

It's a bit like asking if you can take a photo with a large object in the front and remove it to show the background. The answer is yes, if you composited the object yourself and still have the original psd, but once you flatten the image to a JPEG it's basically impossible.

 

Actually it IS impossible without having the original multitrack master. You could attenuate the frequency bands that the instrument is in (and maybe use some complex DSP to help identify the correct bands) but that is the best you can do post.