Ambient music is generally characterized by slow and beatless sounds. These sounds could include anything from crashing waves to birds chirping to computer generated synthesizer noises.
The music is usually slow and lush, and
is intended to be listened to while chilling out
or falling asleep. It is definitely not made for dancing.
Some examples of ambient or idm artists are autechre, brian eno, biosphere, pete namlook, global communication, woob, terre thaemlitz, tetsu inoue ...