Notch filter for isolating instruments?
I'm trying to work out how I can isolate instrument parts in a mastered track using Ardour. I'm looking for something (I think it's a notch filter) that allows me to sweep up and down the frequency range boosting a narrow set of frequencies while the rest are suppressed. I've seen mastering engineers doing this while isolating individual instruments or particular frequencies to cut or boost, and would like to be able to do the same for isolating bass guitar parts when I'm transcribing them for a covers band.
Is this something I can do interactively in Ardour? I've tried doing this in the much simpler Audacity - it has a notch filter, but lacks an interface for sweeping through the frequencies to find the range that I want to isolate.