At church today I listened to an organ piece that had a constant pedal note from the beginning to the end of the piece. The strange (and very unpleasant) thing about this pedal note was, that it was in the (very) high register, perhaps in the 6th/7th octave or so.
The sound was unpleasant enough that it reminded me of the worst episodes of my tinnitus. It's therefore easy to understand from a sensory point of view why constant (pedal) notes are preferrable in the lower register - they are simply less irritating than in the higher ones.
However, it also made me wonder about how the register is chosen for a given note (pitch class). Why do pedal notes play a musically (harmonically) more salient role in lower registers?
In short, why is it that a pedal note cannot perform its "key induction" role (communicating the current harmony, e.g. root of the chord) as well if it is in the higher registers?
My only guess is to do with the richer spectra of lower notes, whose overtones overlap with a higher number of notes that appear elsewhere in the current harmonies of a piece.