A tweeter or treble speaker is a special type of loudspeaker (usually dome or horn-type) that is designed to produce high audio frequencies, typically from around 2,000 Hz to 20,000 Hz (generally considered to be the upper limit of human hearing). Specialty tweeters can deliver high frequencies up to 100 kHz. The name is derived from the high pitched sounds made by some birds, especially in contrast to the low woofs made by many dogs, after which low-frequency drivers are named (woofers).