Waves Abbey Road RS56
The Curve Bender
Originally this equalizer was used for mastering purposes at Abbey Road Studios in the early 1950s. Later, engineers began using the RS56 for studio recordings because of its abilities to dramatically manipulate sound – unlike the basic treble and bass EQs found on the mixing consoles of the time. This earned it the nickname "The Curve Bender."
This plugin does not have a steep learning curve, however I find myself liking it a lot as a very powerful and easy to use MS equalizer