MiniDexed is a FM synthesizer closely modeled on the famous DX7 by a well-known Japanese manufacturer running on a bare metal Raspberry Pi (without a Linux kernel or operating system). On Raspberry Pi 2 and larger, it can run 8 tone generators, not unlike the TX816/TX802 (8 DX7 instances without the keyboard in one box). [Featured by HACKADAY](https://hackaday.com/2022/04/19/bare-metal-gives-this-pi-some-classic-synths/), [Adafruit](https://blog.adafruit.com/2022/04/25/free-yamaha-dx7-synth-emulator-on-a-raspberry-pi/), [The MagPi magazine](https://magpi.raspberrypi.com/articles/mini-dexed) (Issue 142 June 2024, [PDF](https://magpi.raspberrypi.com/issues/142)) and [Synth Geekery](https://www.youtube.com/watch?v=TDSy5nnm0jA).
- [x] Produces sound on the headphone jack, HDMI display or [audio extractor](https://github.com/probonopd/MiniDexed/wiki/Hardware#hdmi-to-audio) (better), or a [dedicated DAC](https://github.com/probonopd/MiniDexed/wiki/Hardware#i2s-dac) (best)
- [x] Loads voices from `.syx` files from SD card (e.g., using `getsysex.sh` or from [Dexed_cart_1.0.zip](http://hsjp.eu/downloads/Dexed/Dexed_cart_1.0.zip))
- [x] Menu structure on optional [HD44780 display](https://www.berrybase.de/sensoren-module/displays/alphanumerische-displays/alphanumerisches-lcd-16x2-gr-252-n/gelb) and rotary encoder
- [x] Runs up to 8 Dexed instances simultaneously (like in a TX816) and mixes their output together
- [x] Allows for each Dexed instance to be detuned and stereo shifted
- [x] Voices can be edited over MIDI, e.g., using the [synthmata](https://synthmata.github.io/volca-fm/) online editor (requires [additional hardware](https://github.com/probonopd/MiniDexed/wiki/Hardware#usb-midi-devices))
- Raspberry Pi 1, 2, 3, 4, or 400. Raspberry Pi Zero and Zero 2 can be used but need HDMI or a supported i2s DAC for audio out. On Raspberry Pi 1 and on Raspberry Pi Zero there will be severely limited functionality (only one tone generator instead of 8)
- Raspberry Pi 5 can be used but currently support is experimental: HDMI sound and USB Gadget mode are not available yet, and it is not clear if there are implications for cooling from running MiniDexed. Also, MiniDexed is currently not taking advantage of the higher processing power of the Raspberry Pi 5 yet. *Hence, you may consider using one of the less expensive, older Raspberry Pi boards for your first build.*
- A [PCM5102A or PCM5122 based DAC](https://github.com/probonopd/MiniDexed/wiki/Hardware#i2s-dac), HDMI display or [audio extractor](https://github.com/probonopd/MiniDexed/wiki/Hardware#hdmi-to-audio) for good sound quality. If you don't have this, you can use the headphone jack on the Raspberry Pi but on anything but the Raspberry 4 the sound quality will be seriously limited
- Optionally (but highly recommended), an [LCDC1602 Display](https://www.berrybase.de/en/sensors-modules/displays/alphanumeric-displays/alphanumerisches-lcd-16x2-gr-252-n/gelb) (with or without i2c "backpack" board) and a [KY-040 rotary encoder](https://www.berrybase.de/en/components/passive-components/potentiometer/rotary-encoder/drehregler/rotary-encoder-mit-breakoutboard-ohne-gewinde-und-mutter)
- In the case of Raspberry Pi 4, Update the firmware and bootloader to the latest version (not doing this may cause USB reliability issues)
- Download from [GitHub Releases](../../releases)
- Unzip
- Put the files into the root directory of a FAT32 formatted partition on SD/microSD card (Note for small SD cards which are no longer sold: If less than 65525 clusters, you may need to format as FAT16.)
- Put SD/microSD card into Raspberry Pi 1, 2, 3 or 4, or 400 (Zero and Zero 2 can be used but need HDMI or a supported i2c DAC for audio out)
- Attach headphones to the headphone jack using `SoundDevice=pwm` in `minidexed.ini` (default) (poor audio quality)
- Alternatively, attach a PCM5102A or PCM5122 based DAC and select i2c sound output using `SoundDevice=i2s` in `minidexed.ini` (best audio quality)
- Alternatively, attach a HDMI display with sound and select HDMI sound output using `SoundDevice=hdmi` in `minidexed.ini` (this may introduce slight latency)
- Attach a MIDI keyboard via USB (alternatively you can build a circuit that allows you to attach a "traditional" MIDI keyboard using a DIN connector, or use a DIN-MIDI-to-USB adapter)
- If you are using a LCDC1602 with an i2c "backpack" board, then you need to set `LCDI2CAddress=0x27` (or another address your i2c "backpack" board is set to) in `minidexed.ini`
- Boot
- Start playing
- If the system seems to become unresponsive after a few seconds, remove `usbspeed=full` from `cmdline.txt` and repeat ([details](https://github.com/probonopd/MiniDexed/issues/39))
- Optionally, put voices in `.syx` files onto the SD card (e.g., using `getsysex.sh`)
- See the Wiki for [Menu](https://github.com/probonopd/MiniDexed/wiki/Menu) operation
- For voice programming, use any DX series editor (using MIDI sysex), including Dexed
- For library management, use the dedicated [MiniDexedLibrarian](https://github.com/BobanSpasic/MiniDexedLibrarian) software
- If something is unclear or does not work, don't hesitate to [ask](https://github.com/probonopd/MiniDexed/discussions/)!
This project lives from the contributions of skilled C++ developers, testers, writers, etc. Please see <https://github.com/probonopd/MiniDexed/issues>.
- [raphlinus](https://github.com/raphlinus) for the [MSFA](https://github.com/google/music-synthesizer-for-android) sound engine
- [asb2m10](https://github.com/asb2m10/dexed) for the [Dexed](https://github.com/asb2m10/dexed) software
- [dcoredump](https://github.com/dcoredump) for [Synth Dexed](https://codeberg.org/dcoredump/Synth_Dexed), a port of Dexed for embedded systems
- [rsta2](https://github.com/rsta2) for [Circle](https://github.com/rsta2/circle), the library to run code on bare metal Raspberry Pi (without a Linux kernel or operating system) and for the bulk of the MiniDexed code
- [smuehlst](https://github.com/smuehlst) for [circle-stdlib](https://github.com/smuehlst/circle-stdlib), a version with Standard C and C++ library support
- [Banana71](https://github.com/Banana71) for the sound design of the [Soundplantage](https://github.com/Banana71/Soundplantage) performances shipped with MiniDexed
- [BobanSpasic](https://github.com/BobanSpasic) for the [MiniDexedLibrarian](https://github.com/BobanSpasic/MiniDexedLibrarian) software, [MiniDexed performance converter](https://github.com/BobanSpasic/MDX_PerfConv) and [collection of performances for MiniDexed](https://github.com/BobanSpasic/MDX_Vault)
- [diyelectromusic](https://github.com/diyelectromusic/) for many [contributions](https://github.com/probonopd/MiniDexed/commits?author=diyelectromusic)
