AcidBoxMynah is an alternative firmware that turns the Mynah into an acid groovebox. Based on the open source AcidBox project. It provides:
[an] acid combo of tb303 + tb303 + tr808 like synths. Filter cutoff, reso, env mod, accent, wavefolder, overdrive within each 303, per-instrument tunings, hi-pass/lo-pass filter and bitcrusher in drums, send to reverb, delay and master compression
While the original project is headless, the AcidBoxMynah fork provides direct control with the Mynah hardware and adds a number of additional features detailed in the user Manual below. Like the original firmware, the AcidBoxMynah is open source and made available under the MIT license.
To switch to AcidBoxMynah, flash the firmware in the firmware tab of the Mynah webapp. Follow the How to Use instructions on that page.
NOTE: The following webapp tabs are not supported with the AcidBoxMynah firmware: Stem Export, Bounce, Songs, Screen Mirror, and SD Cleanup. AcidBoxMynah files and samples live in their own AcidBox folder on the SD card and won’t overwrite or conflict with standard Mynah files. It’s safe to switch between the standard Mynah firmware and AcidBoxMynah firmware at will.
AcidBoxMynah User Manual
User Manual V1.0
Overview
Firmware Features
The original AcidBox is a great-sounding TB-303 emulation with two synth parts and a drum part. AcidBoxMynah puts that engine to work on the Mynah hardware, providing it with a full physical UI.
Key Hardware Features
24 tactile switches (16 step buttons + 8 function keys).
Single potentiometer for parameter control.
OLED display.
8×2 NeoPixel grid for sequencing and visualization.
Sequencing & Automation
16-step sequencer with per-step note, accent, and slide editing.
16-lane synth automation and 8-lane drum automation.
Scale quantization, swing, and BPM control.
Dual modes: autonomous Jukebox Mode or manual Sequencer Mode.
System & UI Improvements
Runtime drum kit browsing and pattern/song/drum kit SD card organization.
Per-voice mute toggling and quick volume shortcuts (F-key + pot).
Pot-lock protection to prevent unexpected parameter jumps during mode changes.
Decoupled UI polling (Core 0 @ 200Hz) from the real-time audio pipeline (Core 1).
Control Reference
Transport
Button
Function
F8
Start / Stop (Toggle)
Operating Mode
Button Combo
Function
F1 + F8
Sequencer Mode / Jukebox Mode (Toggle)
Part Select
Button
Part
F2
SYNTH 1
F3
SYNTH 2
F4
DRUMS
Part Mute
Button
Function
F2 (double-press)
SYNTH 1 (Toggle Mute)
F3 (double-press)
SYNTH 2 (Toggle Mute)
F4 (double-press)
DRUMS (Toggle Mute)
Drum Voice Selection
Button Combo
Drum Voice
F4 + A1
BD (Bass Drum)
F4 + A2
SD (Snare Drum)
F4 + A3
CH (Closed Hi-Hat)
F4 + A4
OH (Open Hi-Hat)
F4 + A5
CLAP (Hand Clap)
F4 + A6
LT (Low Tom)
F4 + A7
MT (Mid Tom)
F4 + A8
HT (High Tom)
F4 + B1
CR (Crash Cymbal)
F4 + B2
RIM (Rimshot)
F4 + B3
MAR (Shaker/Maraca)
F4 + B4
CLAV (Claves)
F4 + B5
COW (Cowbell)
F4 + B6
CY (Cymbal)
F4 + B7
CONG (Conga)
F4 + B8
TIMB (Timbale)
Drum Kit Selection
Button Combo
Function
F1 + F4
Drum Kit Selection
F1 + F2
Previous Kit
F1 + F3
Next Kit
F4
Load Kit
Parameter Selection (SYNTH 1 & SYNTH 2)
First Select SYNTH 1 or SYNTH 2 (F2 / F3)
Button Combo
Parameter
F1 + A1
CUTOFF (Filter Cutoff)
F1 + A2
RESO (Filter Resonance)
F1 + A3
WAVE (Waveform Shape)
F1 + A4
ENV MOD (Envelope Modulation Level)
F1 + A5
PAN
F1 + A6
DELAY (Delay Send)
F1 + A7
REVERB (Reveb Send)
F1 + A8
VOLUME (Part Volume)
F1 + B1
SLIDE (Mark steps as slides with A1-8, B1-8. Set the slide speed with the potentiometer.)
F1 + B2
ACCENT (Mark accented steps with A1-8, B1-8. Set the accent level with the potentiometer.)
F1 + B3
ATTACK (Envelope Attack)
F1 + B4
DECAY (Envelope Decay)
F1 + B5
DISTORTION
F1 + B6
OVERDRIVE
F1 + B7
SATURATOR
F1 + B8
TUNING
Parameter Selection (DRUMS)
First Select Drums (F4)
Button Combo
Parameter
F1 + A1
CUTOFF (Filter Cutoff)
F1 + A2
RESO (Filter Resonance)
F1 + A3
SN TONE (Snare Tone)
F1 + A4
BD DECAY (Bass Drum Decay)
F1 + A5
BD TONE (Bass Drum Tone)
F1 + A6
DELAY (Delay Send)
F1 + A7
REVERB (Reveb Send)
F1 + A8
VOLUME (Part Volume)
Sequencer Controls
Button Combo
Parameter
A1 – A8, B1 – B2
Toggle steps on/off
A1 – A8, B1 – B2 + POT
Adjust pitch per step
F1 + POT
Record automation for current parameter
F5
PART CREATE (Create a note pattern on the current part. Confirm with F5.)
F8 + F5
PART CLEAR (Clear the current part. Confirm with F5.)
F6
PATTERN CREATE (Confirm with F6)
F8 + F6
PART CLEAR (Clear the current pattern. Confirm with F6.)
