Also some of the frequency spectrum lopsidedness could be explained by the properties of our ears, to which modern music is acutely tuned. Look up "A weighting"

Also some of the frequency spectrum lopsidedness could be explained by the properties of our ears, to which modern music is acutely tuned. Look up "A weighting" as an example "loudness" space, which differs from straight amplitude/SPL because of how much less sensitive the average person is to bass than to, say, 2.5kHz tones.