Hi, I'm looking for some harmonizer pedal suggestions... here's what I'd like... Ability to add two harmonies, by semitone, definitely higher harmonies, but lower would also be cool, but not necessary, and it shouldn't be dependent on key. Possible ability to turn individual harmonies on and off Ideally, true bypass Does such a pedal exist? I've looked into a few things, most seem to either only add one, or offer set intervals... I'd like to be able to choose the intervals. I already have an MXR bass octave, so I'm not too concerned about lows, I'd like to add the highs. Thanks!