Crazy idnit, Greg? I wish I could remember exactly how Will Gunn explained it, but the words he used somehow got through to me that using the mid control on my F-1X at full-on was almost like a gain stage, and the bass and treble then became the tone-shaping tools. Since then, I have found that for most applications, my F-1X is set to (appox.) 1.75 Bass × 8.25 Mid × 2.50 Treb. with both the 'Bright' and 'Deep' switches disengaged. These settings are a kinda' "mid-scooped" starting point for my 5-string Alembics, but vary just a little for the 4-string models. For instance I might flick the 'Deep' switch, or boost the Bass a touch. They change quite a bit for other basses, depending upon which one is on deck. The hardest thing for me, (because I seldom if ever load up all that gear for a gig) was replicating (enough of) that glorious sound with the Mesa Walkabout/Scout 15 I gig with regularly. It took some doing, but I found it.
