Changing each seperate clip to different levels of music/audio volume

I know you can change the audio and/or music sound for the entire video but how can I go about changing the level of background music UP and DOWN per clip? For example, I want the music to be louder when certain clips are just scenery with no talking invloved and lower when there is talking involved. I cant seem to figure out how to individulize the levels of sound per clip!? HELP!!!