When using FM synthesis for melodic sounds, how does the modulation index affect the timbre and harmonic content of the resulting sound?

In FM (Frequency Modulation) synthesis, the modulation index directly controls the amount of frequency deviation applied to the carrier oscillator by the modulator oscillator. The modulation index significantly affects the timbre and harmonic content of the resulting sound. FM synthesis works by using one oscillator (the modulator) to modulate the frequency of another oscillator (the carrier). The modulation index determines the depth or intensity of this frequency modulation. A low modula....