RE2-YM2163 - Project RE:birth 2nd Sound Card
RE2-YM2163 - Project RE:birth 2nd Sound Card
Demo Video
What is it?
Project RE-birth 2nd is the spiritual continuation of Project RE-birth — a legendary open hardware project dedicated to bringing classic FM sound chips back to life.
In 2021, for unknown reasons, the Japanese closed the ym2203.com website, deleted all public schematics, and stopped the distribution of all peripheral hardware. Even with money in hand, it became impossible to purchase any SPFM motherboard or rebirth module. This was deeply frustrating for enthusiasts worldwide.
In the absence of original hardware, I forked almost all RE-birth music modules to truly revive this project. My mission: make FM music chips available to people all over the world — no internal meetings, no mystery stores, no hunger marketing, just long-term stock and fair play for everyone.
The RE2-YM2163 is a YM2163 sound card designed for the SPFM series, featuring the latest YM2163_SPFM_Piano_MIDI_v10 driver. The new version supports 4× YM2163 simultaneously and features an optimized channel allocation algorithm for richer, more expressive polyphony.
About the YM2163 Chip
The YM2163 is a rare and fascinating Yamaha FM synthesis chip — a variant in the OPL family designed specifically for electronic piano and keyboard applications. Unlike the more common OPL2/OPL3 chips used in PC sound cards, the YM2163 was targeted at dedicated musical instrument hardware, giving it a distinctive tonal character prized by FM synthesis enthusiasts.
Its rarity makes it a collector's item, and the RE2-YM2163 is one of the very few ways to experience this chip in a modern, accessible SPFM-compatible format.
Key Features
- Authentic YM2163 FM synthesis — rare OPL-family piano/keyboard chip
- Latest YM2163_SPFM_Piano_MIDI_v10 firmware
- Supports up to 4× YM2163 simultaneously for expanded polyphony
- Optimized channel allocation algorithm for intelligent voice management
- MIDI support — use as a hardware MIDI sound module
- Compatible with RE:birth bus standard
- Works with SPFM Light, SPFM Lite, RESPFM, IAP-RESPFM and more
- Classic NE5532 dual op-amp for excellent audio output quality
- Adjustable volume control on-board
- Excellent digital-to-analog isolation for clean, noise-free sound
- Standardized RE:birth module form factor
- Long-term stock — always available, no artificial scarcity
Compatible Mainboards
- SPFM Light
- SPFM Lite (2 slots)
- RESPFM
- IAP-RESPFM (4 slots)
- STM32-RESPFM (4 slots)
YM2163 Virtual Piano v10 — Control Software
A high-performance, real-time control application for the RE:SPFM Quad YM2163 hardware platform. Built on the Dear ImGui immediate-mode GUI framework, the software provides comprehensive MIDI routing, intelligent voice allocation, adaptive dynamics processing, and hardware state visualization.
Core Features
- MIDI Input & Routing: USB MIDI, virtual MIDI cables, and Standard MIDI File (Format 0/1) playback. Sub-millisecond latency with full CC support (sustain, volume, modulation, pitch bend)
- Dynamic Voice Allocation: 16 MIDI channels → 24 physical YM2163 channels across 4 slots. First-fit + priority-based voice stealing (age, velocity, envelope state). Per-slot enable/disable, mute, solo, and hot-swap support
- Adaptive Velocity Mapping: Continuous histogram analysis over 1024-event sliding window. Auto-adjusts attenuation mapping based on input dynamics — ensures optimal contrast regardless of source MIDI compression
- Synthesis Parameter Control: 5 timbres (Piano, Strings, Organ, Clarinet, Half-Coded), 4 envelope presets (Decay/Fast/Medium/Slow), 3 pedal modes (Disabled/Piano/Organ), master volume, octave transpose (±2 oct), fine tuning (±100 cents)
- Real-Time Visualization: 61-key virtual keyboard with velocity color, per-slot channel activity, rhythm VU meters (BD/HC/SDN/HHO/HHD), envelope phase display, MIDI event log
- MIDI File Playback: Directory browser, playlist, auto-play, tempo override (25–200% BPM)
- Configuration Management: JSON preset save/load, hardware calibration, clock drift compensation
Performance Specifications
- MIDI Input Latency: <1ms
- Register Update Rate: 1000 updates/second
- UI Refresh Rate: 60 FPS (vsync)
- Voice Allocation Time: <0.5ms
- Supported Polyphony: 24 voices + 20 rhythm channels
Technical Stack
- GUI: Dear ImGui (immediate-mode, OpenGL 3.3 Core Profile)
- MIDI Backend: Windows Multimedia API / ALSA / CoreMIDI
- Serial: USB CDC, 115200 baud
- Threading: Decoupled MIDI, hardware, and UI threads with lock-free queues