The Secret of Parabolic Microphones: Why High Frequencies Are Easier to Capture

Parabolic microphones are renowned for their extreme sensitivity, stemming from their considerable size. Similar to how telescopes use large parabolic mirrors to gather faint light, parabolic microphones use reflecting dishes to harvest faint sounds. However, this design has drawbacks: it's biased towards higher frequencies, leading to a sometimes 'tinny' sound quality, and lower frequencies experience reduced gain, with a cutoff frequency dependent on dish diameter. This article delves into the physics of parabolic microphone operation, explaining its frequency-dependent performance and the physical mechanisms behind its high-frequency gain, including reflection, reciprocity, interference, diffraction, and Huygens' wavelet model.