With polyphonic ringtones more than one musical note is played at the same time.
Unlike regular ringtones, which can only reproduce consecutive notes (monophony), the polyphonic ringtones are able to create realistic-sounding music by synthesizing several notes simultaneously - polyphony. The more notes the synthesizer can play simultaneously, the nicer it sounds. Usually mobile phones synthesizers can reproduce from 4 to 72 simultaneous tones.
Polyphonic ringtones should not be mistaken with the so called "True tones" (also known as "Real tones") which are simply audio recordings, typically in a common format such as MP3, AAC, or WMA.