https://github.com/copych/esp32_sf2_sampler_synthesizer
ESP32-S3 SF2 based wavetable synthesizer. MIDI input, common CCs support. GM compatible. Effects chain.
https://github.com/copych/esp32_sf2_sampler_synthesizer
arduino esp32 esp32-s3 esp32s3 midi midi-device sampler sf2 soundfont
Last synced: about 2 months ago
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ESP32-S3 SF2 based wavetable synthesizer. MIDI input, common CCs support. GM compatible. Effects chain.
- Host: GitHub
- URL: https://github.com/copych/esp32_sf2_sampler_synthesizer
- Owner: copych
- License: mit
- Created: 2025-05-07T12:58:49.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2026-04-07T06:46:49.000Z (2 months ago)
- Last Synced: 2026-04-07T08:28:41.303Z (2 months ago)
- Topics: arduino, esp32, esp32-s3, esp32s3, midi, midi-device, sampler, sf2, soundfont
- Language: C++
- Homepage:
- Size: 688 KB
- Stars: 23
- Watchers: 3
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# ESP32 SoundFont (SF2) Sampler Synthesizer
An SF2 (SoundFont 2) based wavetable synth designed specifically for the ESP32-S3 / ESP32-P4 microcontrollers. This project leverages the enhanced memory capabilities of the PSRAM equipped MCUs to efficiently load and play SoundFont samples, providing a compact and powerful sampler solution. It's cheap and simple, yet powerful.
---
## Overview
The ESP32 SF2 Sampler is a sampler firmware that runs on the ESP32S3 / ESP32P4 variants due to their improved PSRAM and memory management compared to the original ESP32. It supports external DACs like the PCM5102 for high-quality audio output and uses the built-in USB hardware of the MCUs to function as a USB MIDI device. By default, the BOOT button of the DevBoard is configured to cycle through SF2 files on the current filesystem. Long press on BOOT button will switch between Flash LittleFS and SD filesystems.
---
## Features
- **SF2 playback**: Load SoundFont2 banks up to PSRAM size.
- **Filesystem**: Runtime switch between LittleFS and fast 4-bit SD_MMC.
- **USB MIDI**: Plug-and-play MIDI device support.
- **Per-voice filters**: Optional biquad LPF (configurable in `config.h`).
- **Per-channel filters**: Optional CC#74/71-controlled LPF/resonance.
- **Effects**: Reverb (CC#91), Chorus (CC#93), Delay (CC#95).
- **MIDI control**: GM, partially GS/XG-compatible CCs, PC, RPNs, drums on ch.10, GM reset.
- **External DAC**: Works with PCM5102 and similar I2S DACs.
- **ESP32-S3 optimized**: Dual-core, PSRAM, minimal wiring.
- **Optional OLED GUI**: Use a rotary encoder and a button to navigate.
---
## Hardware Requirements
- **ESP32-S3 microcontroller** with PSRAM (OPI PSRAM recommended)
- **External DAC** (e.g., PCM5102)
- USB connection for MIDI and power
---
## I2S DAC (PCM 5102) Pin Connections
| Signal | GPIO Pin |
|--------|----------|
| BCK | GPIO5 |
| DTA | GPIO6 |
| WCK | GPIO7 |
| CS | GND |
These pins can be changed in config.h if needed
---
## SD CARD Pin Connections:
ESP32-S3: these pins can be changed in config.h if needed
| Signal | GPIO Pin |
|--------|----------|
| CMD | GPIO38 |
| CLK | GPIO39 |
| D0 | GPIO10 |
| D1 | GPIO11 |
| D2 | GPIO12 |
| D3 | GPIO13 |
| VCC | 3V3 |
| GND | GND |
ESP32-P4: fixed pins, external 10k pull-up resistors are required
| Signal | GPIO Pin |
|--------|----------|
| CMD | GPIO44 |
| CLK | GPIO43 |
| D0 | GPIO39 |
| D1 | GPIO40 |
| D2 | GPIO41 |
| D3 | GPIO42 |
| VCC | 3V3 |
| GND | GND |
Note that ESP32P4's SD_MMC SLOT0 uses predefined GPIOs and won't let you change them. If you realy want another set of pins, modify config.h and sdmmc.ino `begin()` to use SLOT1
---
## GUI:
GUI requires U8g2 library.
| Signal | GPIO Pin |
|------------|---------------|
| button | 14 |
| encoder pin A | 15 |
| encoder pin B | 16 |
| | |
| display SDA | 8 |
| display SCL | 9 |
These pins can be changed in config.h if needed
---
## Software Setup
### Arduino IDE Configuration
To build and upload this project using Arduino IDE, configure the following settings:
- **PSRAM**: Select **OPI PSRAM**
- **Partition Scheme**: Choose a partition with the most available SPDIFF space
- **USB Mode**: Select **TINY USB**
- **Core Debug Level**: Set to **Info** or lower (higher debug levels may block USB functionality)
- **Upload SF2 files to internal Flash**: use this plugin for Arduino IDE 2.x.x https://github.com/earlephilhower/arduino-littlefs-upload , or ths one https://github.com/earlephilhower/arduino-esp8266littlefs-plugin if you use Arduino IDE 1.x
- **Wire a microSD or SD card** to have a lot of SF2 files to choose from
---
## Usage
1. Connect your MCU board with PSRAM and external DAC according to the pinout above.
2. Load your preferred SF2 SoundFont files onto the device (refer to project documentation for details on loading SF2 files).
3. Connect the ESP32 via USB to your computer or MIDI host.
4. The device will enumerate as a USB MIDI device, allowing you to play samples via MIDI input.
---
## Notes
- This project is **only compatible with the ESP32-S3 / ESP32-P4** due to memory and PSRAM requirements.
- Using a core debug level above **Info** may interfere with USB MIDI functionality.
- Ensure your external DAC is properly powered and connected for optimal audio quality.
---
## Contributing
Contributions, issues, and feature requests are welcome! Feel free to open a pull request or issue on the GitHub repository.
---
## License
This project is licensed under the MIT License. See the [LICENSE](LICENSE) file for details.
---
## Links
- [Free SoundFonts](https://github.com/ZmeyKolbasnik/Instruments/tree/master)
- [ESP32-S3 Documentation](https://www.espressif.com/en/products/socs/esp32-s3)
- [SoundFont 2 Specification](https://en.wikipedia.org/wiki/SoundFont)
- [ESP Partition Excel calculator](https://github.com/copych/ESP32-S3_SF2_Sampler_Synthesizer/tree/main/partitions)
---
Enjoy your ESP32-S3 powered sampler!