Auditory masking
A loud sound renders quieter sounds nearby inaudible, even though they are still present in the signal.
R. L. Wegel and C. E. Lane at Bell Labs made the first systematic measurements in 1924. A tone mostly masks sounds close to it in frequency, and the effect spreads much further upwards in the spectrum than downwards: a bass line can bury a faint high-pitched sound, but rarely the reverse. The width of the affected region is set by the ear's critical bands.
Masking also works in time. A loud event hides what follows it for up to roughly a hundred milliseconds and — less intuitively — a few milliseconds of what came before, because the brain processes strong signals faster. The whole premise of perceptual coding is that anything you cannot hear does not need to be stored.