The fact that most drivers think they are better than everyone else remind me of the line in Dire Straits "Industrial Disease", at Speaker's Corner:
"Two men say they're Jesus. One of them must be wrong."
Regarding tone controls, Doug Self has an interesting design where there is switchable turnover frequencies, and a defeat switch.
Or the be-all and end-all, which was the long out of production Cello Audio Palette. Originally designed by Richard Burwen under contract to Mark Levinson. Burwen's design spec, design description, and his implementation is here
http://www.burwenaudio.com/images/CE...IO_PALETTE.pdf . Levinson did not like the idea of lots of NE5532's and built the production version using discrete op-amps. Cheap, it was not.
Craig