Voice and singing are fundamental to music. Scales and content reflect our personal culture. Something beautiful and inspiring to one person may be a boring cacophony to another. Viewing musical evolution from the perspective of culture is therefore varied and individual. Input from science is generally less obvious, except for changes generated from acoustics of buildings, broadcasting, and electronic sound equipment. Medical studies reveal how we form sounds and tone quality, and modern electronic signal processing shows the complexity of the harmonic content of singing. The changes between sweetness, harshness, carrying power, and so on, all depend on not just volume, but the fundamental note and its harmonics, plus all the other frequencies generated in our vocalization. One fundamental may have 50 or more other frequencies. This signal processing tool is invaluable for understanding voice production.
Full-Field Detection with Electronic Signal Processing