This main page is where you’ll find sections with a variety of topics and articles related to tweeter speakers. There’s some great info here to help answer your questions.
What is a tweeter?
A tweeter is a type of loudspeaker unit especially designed to produce high-frequency musical audio (also called a treble speaker). Tweeters are helpful for great sound as they can more efficiently (and accurately) provide treble sound that many speakers cannot or have poor performance with.
Tweeter speakers typically have a frequency output range from about 3 kiloHertz to 20 kiloHertz, the upper limit of human hearing. Tweeters can be used as an add-on alongside other full range speakers for additional high-frequency sound performance, although they’re typically part of a 2-way or 3-way speaker system.
As tweeters are sensitive to lower frequencies which can cause distortion and even damage, nearly all require a high pass crossover to prevent midrange and bass frequencies from reaching them.
While more exotic designs exist, the most common have a traditional permanent magnet and voice coil assembly just like other standard speaker types. However, they use a smaller cone or dome size due to the smaller wavelength of high frequency audio.