High frequency speaker driver used to reproduce frequencies typically above 2,000 to 3,000 Hz all the way up to 20,000 Hz. Tweeters are small in size (often one inch or so in diameter) due to their task reproducing small sound waves (a 20 kHz sound wave has a wavelength of only about two thirds of an inch). Tweeters vibrate very quickly thousands of times per second to generate high frequency signals. Many tweeters are made from metal domes while others are made from ribbons, cones and other elements. Tweeters are found in nearly every speaker to reproduce high-frequencies. They are combined with midrange and often bass drivers (woofers) to reproduce the full audible spectrum.