Yes the 2box splash and chick implementation is unique, there's no midi note assigned to the splash but it's triggered by the time threshold of the pedal note. if the pedal it's released quickly it triggers a splash sound, otherwise it triggers a "semi" chick note, semi because it's just a splash sound with shorter decay.I've tried a mimic pro,an efnote and edrumin sending midi to the 2box, all react as you describe, they all trigger a splash and chick at the same time, there's no way to change that in the 2box so triggering it via midi works for all pads but for the hihat is not usable.