>>It has nothing to do with how evolved our ears are. Compared to a dog's, our ears are mediocre at best.

Oh yeah ? Well, my dogs don't care WHAT kind of power cord I use. So there !!

I did read your post, in spite of what my response might indicate

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8