A subwoofer and a midrange driver are designed to handle different parts of the sound spectrum in a speaker system. A subwoofer reproduces very low frequencies, typically below 100 Hz, focusing on deep bass sounds. It's larger in size to move more air, producing the physical sensation of bass. A midrange driver targets the middle portion of the audio spectrum, roughly from 250 Hz to 2,000 Hz, where most vocals, guitars, and other instruments fall.