Frequency Modulation Synthesis
A synthesis method in which one oscillator's frequency is modulated by another, yielding rich, complex tones from simple waveforms without additive filtering.
Instead of blending oscillators, FM lets one oscillator drive the frequency of another. A low modulation index produces subtle, bells-like timbres; a high index yields metallic, grating noise. The Yamaha DX7, released in 1983, made FM synthesis mainstream, but the demoscene was experimenting with crude FM implementations on cheap hardware years earlier. FM was attractive because it packed sonic complexity into minimal CPU cost, making it perfect for real-time chiptune generation on systems with tight budgets.