A³ System
The A³ setup as a DJ plays it: four StemDecks, the desk and A³ Motion
A³ is a live-performance sound system for DJs and live acts: three networked devices and a set of programs that play and move music in the room. A³ Core is the computer that does the audio and the 3D sound field, A³ Mixer is the four-channel desk, A³ Motion steers where each channel sits in the room, and StemDeck plays each track as four stems. They talk to each other over OSC on one network. The pages below describe the system as a whole; each device has its own page in the sidebar.
What A³ is made of
One version is one tag across every repository, so a system is always assembled from parts of
the same version. Each hardware part carries its revision; the boards of every revision sit side
by side in hardware/pcb/, one folder each. Repository, what it is, version, licence:
A³ System the umbrella: installer, CI, pins v03.2 GPL-3.0
├─ a3-core A³ Core and its window v03.2 GPL-3.0
│ └─ a3-beat-analyzer the beat clock v03.2 GPL-3.0
├─ a3-doc the documentation v03.2 CC-BY-SA-4.0
├─ a3-kicad-lib the shared KiCad parts library 37df6cf CERN-OHL-S
├─ a3-mixer A³ Mixer v03.2 GPL-3.0
│ ├─ pcb the boards
│ │ ├─ v0_2 the built board rev v0.2 CERN-OHL-S
│ │ └─ v3_1 the V03 draft rev v3.1 CERN-OHL-S
│ ├─ housing the housing rev v03.2 CERN-OHL-S
│ ├─ firmware the board's firmware rev v03.2 GPL-3.0
│ └─ a3-mixer-ui the virtual desk v03.2 GPL-3.0
├─ a3-motion A³ Motion v03.2 GPL-3.0
│ ├─ pcb the boards
│ │ ├─ v1 the first boards rev v1 CERN-OHL-S
│ │ └─ v3_1 the current board rev v3.1 CERN-OHL-S
│ ├─ housing the housing rev v03.2 CERN-OHL-S
│ ├─ firmware the board's firmware rev v03.2 GPL-3.0
│ └─ a3-motion-ui the Motion UI v03.2 GPL-3.0
├─ a3-pro-dj DJ knowledge, the autopilot v03.2 GPL-3.0
├─ a3-stemdeck the stem decks v03.2 GPL-3.0
│ └─ a3-stem-separator the stems, made off the rig v03.2 GPL-3.0
└─ third-party what A³ is built on
├─ Airwindows PurestGain, SmoothEQ3, Isolator3 2026-10 MIT
├─ BTrack beat tracking 1.0.7 GPL-3.0
├─ IEMPluginSuite ambisonics encoder and decoders v1.16.0 GPL-3.0
├─ JUCE the application framework 9.0.3 AGPL-3.0 OR JUCE-9
├─ kiss_fft FFT inside BTrack 1.3.0 BSD-3-Clause
├─ Neumann KU 100 HRIR the binaural head 2013 CC-BY-3.0
├─ platform-espressif32 the Motion board definition 2026-05 Apache-2.0
└─ Roboto the window's font 1.100141 Apache-2.0
Boards and 3D-print files are CERN-OHL-S-2.0, code GPL-3.0-or-later, the documentation CC-BY-SA-4.0; third-party works keep the licence their authors set. The same tree is in the a3-system README and, live from the installed checkout, on the a3-core window’s ABOUT page.