A tweeter is a type of loudspeaker driver specifically designed to reproduce high-frequency sounds. It normally works alongside larger drivers that reproduce the midrange and bass frequencies, allowing a loudspeaker to cover a much wider range of sound than a single driver could easily reproduce.

In a typical two-way loudspeaker, the tweeter handles the higher frequencies while a woofer or mid-bass driver reproduces the lower and middle frequencies. In a three-way loudspeaker, the tweeter works alongside separate midrange and bass drivers.

A loudspeaker crossover determines which frequencies are sent to the tweeter. The crossover filters out lower frequencies and allows the tweeter to concentrate on the higher part of the audio spectrum. The exact crossover frequency varies depending on the drivers and the design of the loudspeaker.

Tweeters are usually much smaller than bass and midrange drivers. Their lightweight construction allows them to move extremely quickly, which is necessary for reproducing high-frequency sound waves. Conventional dome tweeters are particularly common and may use materials such as fabric, aluminium, titanium or other lightweight materials.

Other types of tweeter include ribbon, planar magnetic and air motion transformer designs. Manufacturers choose different technologies and materials depending on the performance characteristics they want to achieve.

The frequencies reproduced by a tweeter include much of the upper detail and harmonics found in music. Cymbals, percussion and the upper frequencies of voices and instruments all rely on good high-frequency reproduction. The tweeter can therefore have a significant influence on the clarity, detail and overall character of a loudspeaker.

A well-designed tweeter should integrate smoothly with the other drivers rather than drawing attention to itself. Together with the crossover, midrange driver and woofer, it helps the loudspeaker reproduce a balanced and continuous range of frequencies.