I play bouble bass in an 8 piece band playing 50's roots rock music.
The volume of the band tends to get pretty loud at bigger gigs, and since the band consists of 8 persons,
and the stages aren't always big enough, I mostly end up playing close or just in front of my speakers.
To be able to hear I am playing in tune I have to keep the stage volume pretty high, competing with a loud guitarist, three horns and a strong drummer.
That used to give me a lot of feedback trouble.
I am playing and old wooden DB from DDR, with a Fishman Full Circle mic into a Bose T1 as preamp
(it has wonderful presets for the Fishman, etc.)
As cabs I use 2 pieces of MB 410 HR stacked.
Getting the Multiamp, I realized I can put in a chain of up to 6 parametric EQ's, with 2 notch frequencies per EQ to tame any troublesome frequencies.
The other day we had a loud gig in a crowded jazz bar, and I put in a chain of noise gate, one EQ with both high and low shelves to keep out
anything below the lower e and above the high A above the octave on the G-string, followed by two parametric eq's with two notch frequencies each.
the back of my bass was about half a meter from the speakers, and the volume was at full blast.
There was absolutely no feedback. And zero humm and hiss.
I could hear everything I played really well, and the guys were amazed.
They had never played with a rock bassplayer on double bass without problems.
I just smiled...