Radio Music Mk2 User Manual

1. Overview

Radio Music Mk2 plays samples from microSD and maps them to a simple radio-like interface:

  • STATION chooses what to play.
  • START chooses where playback begins, or controls pitch/speed.
  • RESET retriggers playback.

The same module can behave like a straightforward sample picker, a scanned radio dial, a pitch voice, or a looped clock source depending on settings.txt and 8mu control.

2. Front panel behavior

2.1 STATION section

  • STATION knob selects the current station/file in the active bank.
  • STATION CV adds offset to the knob position.
  • Hold STATION push-switch to enter bank browse mode, then turn STATION to choose bank 0-15.
  • Release the switch to return to playback with the selected bank.

Practical note: the firmware only accepts bank folders that contain playable audio.

2.2 START section

  • START knob has two roles:
    • Start mode: start position within the file.
    • Pitch mode: pitch/speed control.
  • Press START push-switch to toggle Start mode and Pitch mode.
  • START CV follows the same mode:
    • Start mode: start-position offset.
    • Pitch mode: pitch CV input.

2.3 RESET section

  • RESET button retriggers playback.
  • RESET jack is dual-purpose:
    • pulseMode=0: trigger input (acts like RESET button).
    • pulseMode!=0: trigger output (input is disabled).
  • Long-holding the RESET button increments bank repeatedly.

2.4 LEDs

Main LED uses are:

  • bank display while choosing banks,
  • VU/progress display during playback,
  • startup and error patterns.

showMeter controls playback display style (bank, VU, or position/progress).

3. SD card setup and file organization

3.1 Card type and format

  • Supported cards: SDHC/SDXC microSD.
  • Filesystems: FAT32 and exFAT.
  • Use an MBR partition table.

3.2 Bank structure

  • Put playable files inside root folders whose names start with 0..15.
  • Examples: 0, 01 drums, 7_voice, 15-koto.
  • Audio files in SD root are ignored.

3.3 Station order

  • Files are ordered lexicographically.
  • Use zero-padded numeric prefixes if you want numeric order:
    • good: 000_kick.wav, 001_snare.wav, 010_hat.wav
    • avoid: 1.wav, 10.wav, 2.wav

3.4 Subfolders

Subfolders inside a bank become station entries.

next folders (sequential):

  • Folder name ending with next: sequential child selection on reset.

Non-next folders (random):

  • Any other folder name: random child selection on reset.

Nested folders:

  • Nested subfolders are supported.

This lets one station represent a rotating phrase set, drum chain, or randomized variation pool.

4. Supported audio formats

4.1 WAV and AIFF

Accepted:

  • sample rates: 8k, 11.025k, 16k, 22.05k, 44.1k, 48k, 88.2k, 96k
  • bit depth: 8/16/24-bit integer
  • channels: mono or stereo (left channel is played)

Not accepted:

  • compressed WAV/AIFF variants
  • 32-bit PCM playback path

4.2 RAW

  • .raw is read as 44.1kHz 16-bit mono PCM.
  • File must be non-empty and have an even byte length.

5. settings.txt in daily use

5.1 Where settings live

  • Global defaults: /settings.txt at SD root.
  • Bank overrides: /yourbank/settings.txt.
  • If root settings.txt is missing, firmware writes one with defaults.

5.2 Syntax rules

  • key=value
  • # starts a comment to end-of-line
  • key names are case-insensitive
  • spaces and tabs are ignored (including inside key names)

Example:

# equivalent lines
Start Pot Immediate = 1
startpotimmediate=1

5.3 Settings you will use most

Playback behavior:

  • loopMode: 0 none, 1 forward, 2 ping-pong
  • tunerMode: 0 switch, 1 fade, 2 radio
  • speedMode: 0 tape, 1 notes, 2 90s/time-stretch
  • fadeMode: 0 constant-power, 1 linear
  • crossfadeTime: fade time in ms

Control response:

  • stationPotImmediate, stationCVImmediate
  • startPotImmediate, startCVImmediate
  • pitchPotImmediate, pitchCVImmediate
  • startCVDivider (coarsens/fines start-position stepping)

Display and quality:

  • showMeter: 0 bank, 1 VU, 2 progress
  • meterHide: how long bank number stays visible after bank change
  • highQuality: 1 high-quality path, 0 lo-fi path

Reset jack behavior:

  • pulseMode: 0 reset input, non-zero pulse output
  • pulseOutDividesCustomLoop: pulse timing based on 8mu loop window or full file

Subfolder reselection timing:

  • reselectSubdirOnStationChange: update subfolder choice only on reset (0) or also on station change (1)

6. Working with 8mu

6.1 Connection

  • Connect 8mu to RM2 USB.
  • RM2 responds to incoming MIDI CC/note data used by 8mu defaults.

6.2 What 8mu controls

In normal 8mu use, sliders cover:

  • pitch,
  • pitch range,
  • loop start,
  • loop end,
  • speed mode,
  • loop mode,
  • tuner mode,
  • pulse mode.

Buttons map to:

  • pause/slowdown hold,
  • reset trigger,
  • motion-control hold,
  • pulse multiply/divide toggle.

6.3 Returning to local-only control

RM2 drops out of active remote state only after:

  1. no incoming MIDI for a short timeout, and
  2. all 8mu slider values are at zero.

If a slider is left up, RM2 can stay in remote-controlled behavior.

7. Calibration (START CV 1V/oct)

Use this when pitch tracking is off in Pitch mode.

7.1 Enter calibration mode

  1. Power off the module.
  2. Hold the START push-switch while powering on.
  3. Release after startup flashing begins.

7.2 Calibration workflow

  1. Wait for alternating middle LEDs (module is listening).
  2. Patch a stable 1V/oct source into START CV.
  3. Play the same note across several octaves (1V spacing).
  4. Each recognized octave lights one indicator LED.
  5. Finish by either:
    • capturing all available octaves, or
    • pressing RESET after at least two octaves are captured.

7.3 Results

  • Success: top LEDs flash rapidly.
  • Failure: top LEDs fade out.
  • Successful calibration is stored in internal flash and survives power cycles.

Tips:

  • Use a stable quantized source.
  • If full-range capture fails, try three central octaves first.
  • Re-run calibration if rack power distribution changes significantly.

8. Special startup modes

8.1 USB mass-storage mode (SD reader)

  1. Power off.
  2. Hold STATION push-switch while powering on.
  3. Connect USB to computer.
  4. Module appears as removable storage for SD content edits.
  5. Press RESET to reboot back to playback mode.

Note: this mode is convenient for editing settings.txt and small file changes, but transfer speed is modest.

8.2 Firmware update mode (RP2040 bootloader)

  1. Get the correct .uf2 firmware file.
  2. Power off.
  3. Hold RESET + STATION push + START push.
  4. Power on while holding all three controls.
  5. Connect USB; the RP2040 boot drive appears.
  6. Copy the .uf2 file to the boot drive.
  7. Wait for reboot (or power-cycle manually if needed).

If no boot drive appears, repeat the power-on button hold and verify cable/USB power.

9. Troubleshooting

  • No audio:
    • confirm files are inside 0..15 bank folders, not SD root.
    • verify format is supported (start with 16-bit 44.1k WAV).
  • Reset jack not retriggering:
    • check pulseMode; non-zero turns that jack into output.
  • Unexpected station order:
    • rename files with zero-padded numeric prefixes.
  • Pitch tracking inconsistent:
    • re-run calibration with stable 1V/oct source.
  • 8mu feels “stuck on”:
    • move 8mu sliders to zero and stop MIDI input briefly.
  • Settings edits caused unpredictable behavior:
    • remove or rename settings.txt, reboot, and let RM2 regenerate defaults.

10. Next document

For full limits, complete setting key list, MIDI mapping, and implementation-level behavior, use docs/radio-music-module-reference.md.