Harmony refers to the "vertical" Seems of pitches in music, which suggests pitches which might be performed or sung with each other concurrently to create a chord. Normally, this means the notes are performed concurrently, Though harmony could also be implied by a melody that outlines a harmonic structure (i.e., http://icrodarisoveria.edu.it/chamilo/app/upload/users/2/2507/my_files/difference-between-mp3-and-wav-audio-files.html