| I've owned several Uni-Vibe and Uni-Vibe type pedals. They work well on bass but keep in mind there will be some amplitude modulation. Modulating low end probably wouldn't be a concern on piccolo bass though anyway. Uni Vibe pedals aren't popular on bass and I think it's because it's hard to find a scenario in which they sound good. Like on guitar, you have to play a certain way with them.
But that being said, I listened to some soundclips or videoclips of the Soul Vibe awhile back and was very unimpressed. It sounded like a mediocre take on a Uni-Vibe pedal. I think there are better options out there if that's the sound you're going for. | 
