In classic FM synthesis, sine waves are used as modulator and carrier waveforms. The EFM1 modulator oscillator provides a number of additional digital waveforms, which extend its sonic capabilities significantly. These waveforms contain additional harmonics that add a new level of richness to the resulting FM sounds.
Turn the Wave parameter knob.
If you turn the knob to the full-left position, the modulator produces a sine wave.
If you turn the knob clockwise, you step—or fade—through a series of complex digital waveforms.