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FM synthesis is a sound-design–driven electronic style built around frequency modulation techniques, where one oscillator (the modulator) alters the frequency of another (the carrier) to create complex, evolving spectra. The result is famously bright, glassy, and metallic timbres—bell tones, electric pianos, plucks, basses, and inharmonic percussion—that are difficult to achieve with subtractive or wavetable methods. As a musical aesthetic, FM synthesis coalesced around the Yamaha DX series (especially the DX7, 1983) and later 4‑operator units like the TX81Z, spreading through 1980s pop, city pop, new age, jazz fusion, and game music. Its signature presets (e.g., "E. PIANO 1", "Lately Bass") defined the sonic palette of mid‑80s to early‑90s recordings, while FM chips in consoles and arcades shaped the sound of an entire era of video games. Today, FM remains a distinct compositional palette: crystalline highs, punchy transient detail, and harmonically rich but precise tones that can feel both futuristic and nostalgic.

Soundtrack is music created to accompany and enhance visual media such as film, television, and video games. It includes original scores (instrumental or vocal music composed specifically for the picture) and, at times, curated compilations of pre-existing songs. Stylistically, soundtrack is a meta-genre that can encompass orchestral symphonic writing, jazz, electronic and synth-driven textures, choral forces, popular song, and experimental sound design. Its defining trait is functional storytelling: themes, motifs, harmony, rhythm, and timbre are shaped by narrative needs, character psychology, pacing, and editing. Common features include leitmotifs for characters or ideas, modular cues that can be edited to picture, dynamic orchestration for dramatic range, and production approaches that sit well under dialogue and sound effects. Because it must synchronize to picture, soundtrack often uses clear dramatic arcs, tempo maps, and hit points.