Specifications

Current target spec. Some details subject to change during development. Rev. 0.1 — March 2026

Specification Value
Platform Teensy 4.1 600 MHz ARM Cortex-M7 — PJRC Audio Shield
Audio 44.1 kHz / 16-bit stereo Stereo out (3.5 mm TRS) — Headphone out (3.5 mm TRS)
Synthesis FM, Subtractive, Wavetable Switchable and layerable per track — Phase 4 target
Tracks 8 tracks 4 synth + drum machine + 3 MIDI out — Phase 3 target
Sequencer 16-step per track Parameter locks — Pattern chaining — Phase 3 target
Controls 10 knobs, 32 pads (4×4×2), 6 transport buttons Black anodized aluminum knobs — Black silicone pads with red LED backlight
Display 128×64 OLED — white on black Adjustable brightness — no color, no backlight bleed
Connectivity USB-C (power + MIDI) — MIDI in / out / thru (5-pin DIN) — Stereo out — Headphone out Phase 2+ target for full MIDI I/O
Power Internal 18650 Li-ion cell — USB-C charging Estimated 4–6 hr battery life — Phase 3 target
Storage MicroSD card slot (Teensy 4.1 built-in) Pattern save/load — Sample storage — Phase 3 target
Enclosure PA6-GF matte black — walnut side panels Glass-filled nylon body — Dark walnut riser, 15° angle — Black oxide hardware throughout
Serviceability Fully user-serviceable M3 black oxide screws — brass heat-set inserts — no glue, no clips
Firmware Open source Arduino / Teensyduino — PJRC Audio Library — Custom code welcome — GitHub
Hardware Design Open source STL files for all printed parts — Schematics — PCB files — GitHub — print your own

Features

Sound engine

Three engines. One box.

CMS Alpine runs FM, subtractive, and wavetable synthesis on the same hardware, switchable per track. Not a jack of all trades — each engine is implemented properly, informed by the Mutable Instruments approach: do it right or don't do it.

  • 4-operator FM with configurable algorithms
  • 2-oscillator subtractive with resonant filter
  • Wavetable with interpolated scanning
  • Per-voice ADSR envelope, LFO modulation
  • 4–6 voice polyphony (Phase 2+)
Sequencer

16 steps. 8 tracks. Stay in the groove.

The sequencer is direct. Each of the 16 red-backlit pads is a step. Press to toggle. Hold to set parameter locks — pitch, filter, envelope, anything on a knob can be locked to a specific step. No mode switching, no submenu, just the pads and what they do.

  • 16-step sequencer per track
  • Parameter locks on every knob
  • Pattern chaining (Phase 3)
  • Swing and groove quantize
  • MIDI clock in / out sync
Enclosure

Materials that earn their place.

The body is PA6-GF — glass-filled nylon. Not cheap ABS, not expensive aluminum. PA6-GF is what engineers specify when the part needs to be rigid, chemically resistant, dimensionally stable, and naturally matte black. It feels dense. It doesn't flex. The walnut riser is hand-finished with Danish oil — nearly black stain, grain still visible.

  • PA6-GF matte black body
  • Dark walnut riser, 15° ergonomic angle
  • Black anodized aluminum knobs, knurled grip
  • M3 black oxide hardware throughout
  • Brass heat-set inserts — no plastic threads
Open source

Open firmware. Open hardware.

The firmware is open source — written in Arduino/Teensyduino, readable and buildable by anyone with a C++ compiler. The enclosure is open source — when units ship, every STL file, schematic, and PCB layout goes on GitHub. Print your own case. Modify the panel layout. Fork the firmware and build something we didn't think of. None of this is locked down.

  • Open source firmware — Arduino/Teensyduino, C++
  • STL files for all 3D-printed parts — free to download and modify
  • Schematics and PCB files published on GitHub
  • USB-C MIDI — class-compliant, no drivers needed
  • Expansion pins accessible and documented

Product photography in progress. Renders and photos will appear here.

Units are not available yet.

CMS Alpine is in active development. Leave your email and we'll send one message when it's ready to order. No newsletter, no spam.