This growing consensus about the appealing nature of low and even order harmonics and repellent nature of high an odd order harmonics is fascinating. From a biological standpoint it suggests the question, “how did this come to be“? If we step outside the arena of audio reproduction and look at acoustics and hearing by themselves I would say from my own experience that certain environments, rooms, auditoriums have better or worse “acoustics“. So do we encounter pleasing and displeasing harmonics naturally and could this be a foundation to explain how evolution tunes our hearing to prefer one over the other. I don’t know. I offer it as a hypothesis. Maybe others here with more expertise in acoustics can comment. I do know that if you take an acoustic instrument outdoors it becomes a mere shadow of itself sonically, likewise in an anechoic chamber. However in certain spaces the same instrument becomes much more pleasing. Could it be possible that this is the effect of these various types of harmonic distortion occurring naturally? Tying it back to evolution could the more pleasing acoustic environment also have been the better one for us to function in both predators and prey? @anders65 thanks for your comments which spurred this line of thought.
