tweeter

…high-frequency speaker is called a tweeter. In many sound reproduction systems a third, or midrange, speaker is also used, and in a few systems there are separate “subwoofers” and “supertweeters” to reproduce the extremities of the audible spectrum.

…while a smaller speaker, or tweeter, produces the higher frequencies. In such a two-way system, a passive electronic circuit called a crossover network is employed to direct the higher and lower frequencies to the appropriate loudspeaker. A larger or more efficient three-way system may add a midrange speaker, helping to…