These questions were recently asked by students of mine:
1. For sound intensity level, why is the decibel unit is used instead of
the bel (1 dB = 0.1 bel)?
2. Do the "f holes" in violin sound boards play any role in the quality of
the sound produced? Do these openings somehow "compliment" the shape of
the resonant cavity? Acoustic guitar sound boards are "figure 8" shaped,
yet the openings are circular.
3. In a choir, why are the higher-frequency notes often easiest heard? It
could be because they sing louder. Or is it because our ears, being closed
pipes, are most sensitive around 3000 Hz?