ReaEq an option. I use it for everything bass, 6 string. Free if you can't afford the expensive stuff and works rock solid in Sonar. Comes with a bundle of other interesting plugs.
Lacks a lot of the automated functions in the likes of Melda eq's, but hard core bread and butter. One of the things I appreciate most is the straightforward GUI presentation. Always know where I'm at.
Allows as many bands as needed, starts with 4. Allows choice of 10 different band applications on any band.
Has the standard gain, bandwidth and center point on any band.
Has a real time graphic of the freq response of the track which updates as the eq is changed so you can see what you are doing with the original signal.
Tip for bass is to use default band 1 (set to a low pass), reduce the band width to the point you get a sliding resonance. Works killer on drums as well.
http://www.reaper.fm/reaplugs/ Can't argue the price. Admit my ears are a bit blown out over the decades, and would be really interested if anyone thinks this is a piece of crap in the light of better options, and why. Just here to learn.
John