Is it correct that only when play cD, then tweeter will have sound? no sound for normal radio?
Tweeter is for Hi frequency.
Audio equipment like speaker generate the sound via the frequency been set. Notice the freq required.
It does not mean radio or anything other things.
Same thing like woofer, it only accept low frequency.
That's some people have the equaliser to tune the sound. Also, that's where cross over comes in to separate the frequency to mid bass and tweeter.
Look at ur hi fi system. Some have 1 tweeter and 1 mid bass and some 1 tweeter and 2 more cones. Different frequency set.
=)