For Someone if still having hard time to understand

Observable: is like a radio station that broadcasts new songs after some time

Observer: It's radio that actually receives those signals(data) from that radio station and converts those into(song).

but remember until we turn on the radio or basically we subscribe it we can't listen to it right?

In actually angular (Observers are just objects with three callbacks, one for each type of notification that an Observable may deliver)

And yeah this is what a subscriber is people who want to listen(in actual example could a be person that subscribes to some Observable)