A treble speaker or tweeter is a special type of loudspeaker (typically dome or horn-type) that is designed to produce high audio frequencies, typically from around 2,000 Hz to 20,000 Hz .  Specialty tweeters can deliver high frequencies up to 100 kHz. The name is derived from the high pitched sounds made by some birds.  Traditional speakers produce sound by using an electromagnet to move a flexible cone back and forth. They use drivers to help translate electrical signals into physical vibrations so that you can hear recorded sounds. A tweeter is the type of speaker driver that produces the highest range frequency.