The Source Audio EQ 2 is...on both of my pedalboards. High pass filter, low pass filter (AKA cab sim - other than rolling off low end like a speaker (which I don' t want) what a cab sim mainly does is takes the fizz/edge off of things, and a good lowpass does that just as well. The eq is fully parametric - any band can be any frequency, any Q, and any magnitude you want it to be.. There's also a limiter built in, control over gain, and a tuner - it does so many needed things that it's the "always on" thing on my boards. I have presets set for each of my basses - all I do at a gig is power it on, and choose the preset for the bass I'm playing, and levels and eq are set for my rig. Its not cheap, bujt for waht it does, and that it does it in one pedal, it's a bargain. I've had the Q strip and the Empress, and the EQ 2 is a better deal all around.
The UI is very good - there's almost no learning curve (you gotta learn that the little wrench symbol is how you engage the unit you plugged into your computer - from there on, it's very straightforward, and yet powerful.