Brume is a 24-voice multi-timbral desktop synth for the CM5

FM Six operators across twelve algorithm topologies, per-op ratio and level, global feedback, a per-voice FM-index envelope, and a voice-tail state-variable filter with its own envelope — DX-style FM with subtractive shaping on the way out. A desktop multi-timbral music machine with four synthesis engines, a 10″ touch surface, and one cable to your DAW. Brume runs four synthesis engines with a shared voice tail (state-variable filter, amp envelope, modulation router), so patches stay coherent across very different sources. Each engine has its own mechanism for continuous spectral change: algorithm routing and per-voice FM-index envelopes in FM, a scanning window in Harmonic, cascaded wavefolding in Timbral, grain scatter in Granular. No samples sit anywhere in the signal path; every voice is generated from live math. Six operators across twelve algorithm topologies, per-op ratio and level, global feedback, a per-voice FM-index envelope, and a voice-tail state-variable filter with its own envelope — DX-style FM with subtractive shaping on the way out. Eight harmonics with Gaussian scanning, per-harmonic waveform morph, FM on the fundamental, spectral tilt, and odd/even balance. Triangle core through a wave-multiplier shaper with linear FM, sub-oscillator, self-modulation feedback, and expanded symmetry. Pitched clouds of micro-oscillator grains with morphable waveforms. Density, scatter, drift, and FM within grains. MIDI in, voice allocation, modulation, filter, envelope, mixer. Sends to delay and reverb. A Lua FX slot for custom processing. One USB cable carries multi-channel audio out, bidirectional MIDI, and clock. Class-compliant — no drivers, no manager app. 4 engines · 24 voices · dry + sends rendered per part. Class-compliant. One port. Stereo out plus planned per-part stems. Bitwig, Logic, Ableton, Reaper. Arm a track, point at Brume, record. Raspberry Pi OS Lite, Rust audio runtime, 10.1-inch capacitive touch. Boots fast. Bridges to your DAW over USB. Boot and play. The hardware is a deliberate assembly of off-the-shelf parts — the instrument is the software. Compute Module 5. Quad-core ARM A76, 8 GB RAM, 32 GB eMMC, wireless. CM5 IO Board with USB OTG for multi-channel audio and MIDI to your DAW. HDMI, GPIO, Ethernet. Pick the HDMI touchscreen that fits your build. Brume’s UI is designed around a 1024×600 logical layout and auto-scales to whatever panel you connect — tap into the CM5 touchscreen ecosystem. Reference unit: 10.1″ 1920×1200. Brume installs onto Raspberry Pi OS Lite. The brumectl CLI adds the runtime packages, labwc/webkitgtk shell, audio config, presets, and systemd service; --update refreshes the binary and factory presets over SSH. Korg nanoKONTROL2 is the reference USB-MIDI controller — 8 knobs, 8 faders, transport, and per-strip S/M/R. Brume ships with a default CC-mapping JSON plus a Lua starter script. Novation Launch Control XL 3 positions as the deeper control option — 24 endless encoders, 8 faders, 16 pads, transport. In development as a first-class surface: dedicated CC-mapping JSON with a per-engine page layout, Lua starter scripts. Plug in a class-compliant MIDI controller, touch MIDI learn, save the mapping, then shape the behavior in Lua. Map a controller you like, then share the mapping and a starter script so everyone gets it out of the box.