Ouranos7

Ouranos7 is a free six-operator FM synth by john-crosby-acoustics, entered in the KVR Developer Challenge 2026. It’s an explicit homage to the Yamaha DX7 — the 1983 six-operator FM synth that defined 80s digital sound and was notorious for its buried menu-driven programming. Ouranos7’s pitch is DX7-class tones “without the hardware headache,” the fruit of decades spent in the DX7’s sub-menus.

Architecture

• Six FM operators with a 7×6 FM/AM modulation matrix.
• 25 tuning tables and seven Bézier-curve ADSR envelopes (smooth, editable contour shapes rather than fixed segments).
• The roundup name-checks classic FM territory: electric pianos and that “Danger Zone” FM bass.

Available in AU, VST3, AAX, and CLAP for macOS and Windows. Together with tetraop it makes FM the most represented method in the roundup — one a strict six-op DX-style engine, the other a four-op FM/wavetable hybrid. Source is a press roundup (T3, subjective sound remarks).

Related

john-crosby-acoustics · fm-synthesis · tetraop · synthesizer · kvr-developer-challenge