I like this request. The ability to filter off a little bass from a bass drum, while still sending the bass drum to make it sit in a an environment without booming out the reverb.. Sending a snare with all just a little tidying of the bass, and trimming off the the high a little. Having a Hi Hat, but wanting to keep the energy from the bottom end of a foot close, but to exciting the reverb with it, making it more in focus.
With a delay buss, being able to pull out a lot of bottom end from several sends, but allowing an in key instrument to make more use of it's frequency range, making the others sit more on top of the effect.
Just a horizontal bar, with the band pass showing within the bar. scroll to control LP and shift scroll to controll hi pass, or somthing.