This page further shows the efficiency difference between a multi-level class D amplifier and a conventional class D amplifier. The blue curve indicates the efficiency of a multilevel class D amplifier in a light load power range typically below 5 W for audio systems. There is a 25% to 30% efficiency boost from the red efficiency curve of a conventional class D amplifier below the 1 W power level, which is the listening range for music playback most of the time.