FM-Four is a compact VST instrument that emulates four-operator FM synthesis, inspired by classic Yamaha OPL/OPL2 chipsets. It offers a rich sonic palette, capable of generating a wide variety of harmonic textures and tones. The instrument's design focuses on delivering expressive FM sounds with enhanced control and flexibility.

This VST features eight FM algorithms and four operators, each with coarse and fine tuning options. It includes eight distinct waveforms per operator, ranging from sinusoidal shapes to triangle and square waves, expanding creative possibilities. The multimode LFO can be synced to BPM or set to a random mode, while four filters and an eight-stage envelope generator provide detailed modulation control. Additional sound shaping tools such as distortion, an internal chorus effect, and a 10-band equalizer allow for further refinement of the sound.

FM-Four supports full MIDI learning and VST automation, facilitating seamless integration into any digital audio workstation workflow. It comes with 64 factory presets and a built-in preset manager that allows users to easily edit patch names and organize sounds. The user interface is designed for straightforward operation, featuring pop-up menus that simplify navigation and parameter adjustments.