The vocal tract — the «pipe» between the voice box and the mouth — has a series of resonance frequencies (R1, R2, R3, et cetera), which provide an effective transfer of acoustic power from the vibrating vocal folds to the surrounding air. (scientificamerican.com)
In other words - if I'm not allowed 20 kW of acoustic power on Time Square, why should I be allowed $ 200M of prime time TV? (politics.stackexchange.com)
Usually, the fundamental frequency has the greatest acoustic power, but the very high harmonics, although less powerful, have the advantage of residing in a range above about 3,000 Hz, where the orchestral accompaniment provides less competition. (scientificamerican.com)