So, I was just thinking this recently and thought I should ask the expert collective... Most analog octave pedals can send the clean through alongside the -1. This means that they're parallel in the circuit, at least for part of the path. So, since analog octaves crap out on the low notes... What about a HPF in the octave branch of the circuit, so that the divider only receives the higher notes and the higher harmonics of the lower notes, to try to synthesize against? So if you play an open E, you won't have a mess under it. But the harmonic content could still trigger the octaver to reinforce your E with a hint of synthesized unison-note ... Maybe slope it off below A (55) or so. Knowing my luck this idea has been tried and rejected or something. But I can't see how it wouldn't help.