.

Keeping this in view, what do car audio tweeters do?

Tweeters are the audio drivers in a speaker system that produce the upper range of sound you hear. Because higher sound frequencies have smaller sound waves their size is smaller than the other speakers they work alongside.

Subsequently, question is, what makes a good tweeter speaker? Villchur's invention is still the most common tweeter type; probably about 95 percent of all speaker systems use dome tweeters. Dome tweeters have very smooth response, good dispersion, and average sensitivity. Typical operating range is 2.5 kHz to 20 kHz, and sound quality ranges from basic to excellent.

Besides, are tweeter speakers necessary?

Yes you'll need a tweeter, the high frequencies won't be loud enough for it to sound good.

Do I need a crossover for my tweeters?

If your car audio system uses coaxial speakers, you probably don't need an additional crossover. The high pass filter in this type of amplifier allows you to drive tweeters, and the low-pass filter allows you to drive woofers, without requiring any additional crossovers.