Configuration file

mt32-pi tries to read a configuration file from the root of the SD card named mt32-pi.cfg. Please read the file for a description of all the available options.

⚠️ Note: Don't confuse this file with config.txt or cmdline.txt - they are for configuring the Raspberry Pi itself, and you should not need to alter these when using mt32-pi.

Here are some tips to successfully edit your configuration:

• Use a text editor such as Visual Studio Code or Notepad++ to edit mt32-pi.cfg; they provide color highlighting features to make it easier to read and edit.
• The file is grouped into sections. Section names are written inside square brackets, e.g. settings related to audio will appear under the [audio] section.
• Comment lines start with a #. These lines do not perform any configuration; they simply provide explanation.
• Each setting is represented by a line in the format setting_name = value.

Default configuration

The default configuration file contents are provided below for your convenience:

#                                  ________    _______                      __
#                         __      /_____   `. /____   `.                   /__`
#     ____   ____     __/  /____  _______)  / ______)  / ____  ______      __
#   /   __ v  __  `./__   _____//_____    < /   _____. /____//   ___  `. /  /
#  /  /  /  /  /  /   /  /____  _______)  //  /______       /  /____/  //  .__
# /__/  /__/  /__/    \______//_________. /_________/      /   ______.  \____/
# /////////////////////////////////////////////////////// /  / //// /// // /
#                                                         ```
# mt32-pi.cfg: mt32-pi configuration file.
# Default options are marked with an asterisk (*).

# -----------------------------------------------------------------------------
# System options
# -----------------------------------------------------------------------------
[system]

# Enable or disable verbose startup and error output.
#
# When enabled, outputs more information to the LCD when starting up, and when
# MIDI/UART errors are detected.
#
# This also may hide the boot logo on smaller graphical displays.
#
# Values: on, off*
verbose = off

# Set the default synthesizer to be made active on startup.
#
# If the default synthesizer is unavailable (e.g. missing ROMs or SoundFonts),
# the first working synth is made active.
#
# Values: mt32*, soundfont
#
# mt32:      Use mt32emu (Munt) for Roland MT-32 emulation
# soundfont: Use FluidSynth for SoundFont synthesis
default_synth = mt32

# Enable or disable support for USB devices.
#
# Disable this to speed up boot time if you are not using any USB devices.
#
# Values: on*, off
usb = on

# Set the I2C baud rate/clock speed for all peripherals (Hz).
#
# Most peripherals will work fine at the default speed (400KHz "fast mode"),
# but larger LCD/OLED displays (e.g. 4-line I2C HD44780 and 64 pixel high
# SSD1306) won't be able to refresh at 60FPS at the default setting.
#
# Try increasing this value to 1000000 (1MHz) for a smoother LCD refresh rate.
# If your display doesn't work, try backing off the speed 100KHz at a time
# until it does.
#
# Values: 100000-1000000 (400000*)
i2c_baud_rate = 400000

# Set the timeout for power saving mode (seconds).
#
# After the specified number of seconds of silence, the CPU clock speed will be
# reduced, the audio device will be stopped, and and the LCD's backlight will
# be turned off to save energy (certain I2C displays only).
#
# Any MIDI activity will instantly bring the system out of power saving mode.
#
# If set to 0, power saving mode is disabled.
#
# Values: 0-3600 (300*)
power_save_timeout = 300

# -----------------------------------------------------------------------------
# MIDI options
# -----------------------------------------------------------------------------
[midi]

# Set the baud rate used for GPIO MIDI.
#
# For connecting to standard MIDI devices (i.e. via DIN cable), this should be
# left at the default rate of 31250.
#
# For connecting to PCs, set this to match the baud rate of the other host.
# SoftMPU's serial MIDI mode, for example, uses a baud rate of 38400.
#
# Values: 300-4000000 (31250*)
gpio_baud_rate = 31250

# Enable or disable software "MIDI thru" on the GPIO Tx pin.
#
# When enabled, all data received via the GPIO Rx pin will be re-transmitted
# verbatim on the Tx pin. This may be useful for debugging or for passing MIDI
# data through to another synth.
#
# Values: on, off*
gpio_thru = off

# Set the baud rate used for USB serial MIDI.
#
# The same considerations from the gpio_baud_rate setting above apply here.
# The default value is a PC baud rate and matches SoftMPU's serial MIDI mode.
#
# The range of valid baud rates may vary depending on the chipset of your USB
# serial device, so the range of values suggested below may actually be greater.
#
# Values: 9600-115200 (38400*)
usb_serial_baud_rate = 38400

# -----------------------------------------------------------------------------
# Audio options
# -----------------------------------------------------------------------------
[audio]

# Select audio output device.
#
# Values: pwm*, i2s
#
# pwm: Use the headphone jack
# hdmi: Use the HDMI port
# i2s: Use an I2S DAC
output_device = pwm

# Sample rate of audio output (Hz).
#
# mt32emu uses an internal sample rate of 32000Hz (just like the real hardware)
# which is then resampled to this value.
#
# FluidSynth renders at this sample rate directly.
#
# Values: 32000-192000 (48000*)
sample_rate = 48000

# Set audio rendering chunk size (samples).
#
# A single stereo frame of audio has two samples, and so this value is double
# the number of frames per chunk.
# The smaller the chunk size, the lower the latency, but too low a value will
# cause underruns (distortion artifacts).
#
# Latency is a function of chunk size and sample rate, for example:
# 256 samples / 2 channels / 48000Hz * 1000ms = 2.67ms of latency.
# See documentation for recommended values for various Raspberry Pi models.
#
# The minimum value varies depending on audio output device.
# For PWM, the minimum is 2, for I2S the minimum is 32.
# For HDMI, the minimum is 384, and will be rounded to the nearest multiple of
# 384.
#
# Values: 2-2048 (256*)
chunk_size = 256

# Set whether the stereo channels should be swapped or not.
#
# Use this option to work around wrongly-wired audio hardware.
#
# Values: on, off*
reversed_stereo = off

# -----------------------------------------------------------------------------
# Control options
# -----------------------------------------------------------------------------
[control]

# Set the physical control scheme.
#
# See documentation for GPIO pinouts/wiring details.
#
# Values: none*, simple_buttons, simple_encoder
#
# none:           No physical controls
# simple_buttons: Simple 4-button scheme
# simple_encoder: Simple 2-button + rotary encoder scheme
scheme = none

# Set the rotary encoder type (if used by control scheme).
#
# Different rotary encoders may complete different fractions of a Gray-code
# cycle per detent ("click").
#
# If four clicks are needed for a single movement, try "quarter".
# If two clicks are needed for a single movement, try "half".
#
# Values: quarter, half, full*
encoder_type = full

# Reverse the rotary encoder direction (if used by control scheme).
#
# Some rotary encoders may have their CLK/DAT signals swapped, resulting in
# a reversed rotation direction.
#
# Use this option to correct the direction.
#
# Values: on, off*
encoder_reversed = off

# Enable or disable the I2C MiSTer control interface.
#
# If using mt32-pi with a MiSTer FPGA system and custom hardware to interface
# with MiSTer's User Port, enable this option to allow controlling mt32-pi via
# the MiSTer's on-screen display.
#
# Values: on, off*
mister = off

# Set the timeout for switching SoundFonts (seconds).
#
# When switching SoundFonts using the physical button, there is a short delay
# before loading begins. This option allows you to set the number of seconds to
# wait before loading.
#
# Values: 0-3600 (3*)
switch_timeout = 3

# -----------------------------------------------------------------------------
# MT-32 emulator options
# -----------------------------------------------------------------------------
[mt32emu]

# Set gain factor applied to synthesizer output channels.
#
# This is independent of the master volume that can be set via MIDI SysEx or
# the volume knob.
#
# Values: 0.0-256.0 (1.0*)
gain = 1.0

# Set gain factor applied to reverb wet output channels.
#
# Values: 0.0-infinity (1.0*)
reverb_gain = 1.0

# Select quality level for the resampler.
#
# If set to none, audio output will sound wrong unless you set the sample rate
# option to 32000Hz, which is the MT-32's native sample rate.
#
# Values: none, fastest, fast, good*, best
resampler_quality = good

# Select initial MIDI channel assignment.
#
# The MT-32 uses an unusual MIDI channel assignment by default. On a real MT-32
# this is set using a button combination. Use this option to change the initial
# channel assignment on startup.
#
# Values: standard*, alternate
#
# standard:  Parts 1-8 = MIDI channels 2-9, Rhythm part = MIDI channel 10
# alternate: Parts 1-8 = MIDI channels 1-8, Rhythm part = MIDI channel 10
midi_channels = standard

# Select initial ROM set to use.
#
# If multiple ROM sets are available, this option determines which set to use
# on startup. If the ROM set specified here is unavailable, the first available
# set is used instead.
#
# Values: old*, new, cm32l
rom_set = old

# Set whether the stereo channels should be swapped or not.
#
# The MT-32 interprets values for MIDI CC#10 (panpot) differently to later
# synthesizers, which means that 0 = right and 127 = left; the opposite of what
# is stated in the most recent versions of the MIDI specification.
#
# Enable this option to swap the channels and make MT-32 mode's panning
# behavior match the behavior of SoundFont mode. Note that this can also be
# switched at runtime with a custom SysEx command.
#
# Values: on, off*
reversed_stereo = off

# -----------------------------------------------------------------------------
# SoundFont synthesizer options
# -----------------------------------------------------------------------------
[fluidsynth]

# Set the initial SoundFont to use.
#
# If multiple SoundFonts are available, this option determines which SoundFont
# to use on startup.
#
# On startup, the "soundfonts" directory is scanned for valid SoundFonts, which
# are added to a list and sorted into alphabetical order.
#
# This setting is a zero-indexed offset into that list (i.e. 0 is the first,
# 1, is the second, and so on).
#
# If the index specified is unavailable, the first available SoundFont will be
# used.
#
# Values: 0-255 (0*)
soundfont = 0

# Set the maximum number of voices that can be played simultaneously.
#
# Depending on the complexity of your SoundFont, you may need to reduce this
# value to prevent audio buffer underruns (distortion) when playing music
# featuring lots of notes being played at once.
#
# On the other hand, you may want to try raising this value if your Pi is
# being run overclocked or has a more powerful CPU (e.g. Pi 4/CM4).
#
# N.B. larger file size of the SoundFont does not imply higher CPU usage.
# SoundFonts that use more real-time effects (modulators) are more likely to
# require a reduction in polyphony.
#
# Values: 1-65535 (200*)
polyphony = 200

# The following settings set the default parameters for FluidSynth's master
# volume gain, reverb and chorus effects.
#
# Each setting can be overridden on a per-SoundFont basis by creating a .cfg
# file adjacent to the SoundFont file with the same name. For example,
# when "foo.sf2" is loaded, mt32-pi will look for a file called "foo.cfg" and
# apply any effects settings found inside it.
#
# Full descriptions and valid value ranges for each setting can be found in the
# FluidSynth documentation: https://www.fluidsynth.org/api/fluidsettings.xml
gain = 0.2

reverb = on
reverb_damping = 0.0
reverb_level = 0.9
reverb_room_size = 0.2
reverb_width = 0.5

chorus = on
chorus_depth = 8.0
chorus_level = 2.0
chorus_voices = 3
chorus_speed = 0.3

# -----------------------------------------------------------------------------
# LCD/OLED display options
# -----------------------------------------------------------------------------
[lcd]

# Select LCD driver.
#
# Note that LCDs connected via I2C, you must also set the correct address for
# your device via the i2c_lcd_address option. Consult its datasheet, or see
# our documentation for tested models and their configurations.
#
# Values: none*, hd44780_4bit, hd44780_i2c, sh1106_i2c, ssd1306_i2c
#
# none:         No LCD
# hd44780_4bit: Hitachi HD44780 or compatible (e.g. WS0010, RS0010) character
#               LCD connected to GPIO pins in 4-bit mode (see documentation for
#               pinout)
# hd44780_i2c:  As above, but using an I2C "backpack"
# sh1106_i2c:   Small I2C-based OLED graphical display (usually 1.3")
# ssd1306_i2c:  Small I2C-based OLED graphical display (usually 0.96")
type = none

# Set the width of the LCD.
#
# If the display is a character display, this value is measured in characters.
# Otherwise, for a graphical display, this is measured in pixels.
#
# Note that not all dimension settings are valid; see documentation for valid
# configurations for each LCD driver.
#
# If set to 132, assume this display is an SSD1305 (see wiki).
# Note: the correct settings for the SSD1305 may change in future.
#
# Values: 20-132 (128*)
width = 128

# Set the height of the LCD.
#
# Same characters vs. pixels considerations as for width.
#
# Values: 2-64 (32*)
height = 32

# Set address (hexadecimal) of I2C LCD.
#
# This will be used to communicate with LCDs connected via the I2C bus.
#
# Values: 00-80 (3c*)
i2c_lcd_address = 3c

# Rotate the display output (graphical LCDs only).
#
# Some graphical displays support rotation. Use this option if you need to turn
# the display around.
#
# Values: normal*, inverted
#
# normal:   No rotation
# inverted: The display output is upside down
rotation = normal

# Mirror the display output horizontally (graphical LCDs only).
#
# Some graphical displays display columns right-to-left rather than left-to-
# right. Use this option if you need to mirror the display horizontally.
#
# Values: normal*, mirrored
#
# normal:   No mirroring
# mirrored: The display output is mirrored horizontally
mirror = normal

# -----------------------------------------------------------------------------
# Network options
# -----------------------------------------------------------------------------
[network]

# Select the network mode.
#
# For setting your Wi-Fi SSID and encryption key, see wpa_supplicant.conf.
# Note that if using Ethernet on a Raspberry Pi 3B/3B+, USB must be enabled.
#
# off:      Disable networking
# ethernet: Enable using the Ethernet interface
# wifi:     Enable using the the Wi-Fi interface
#
# Values: off*, ethernet, wifi
mode = off

# Enable or disable DHCP for configuring the network.
#
# If disabled, the manual settings below will be used to configure your network
# interface instead.
#
# Values: on*, off
dhcp = on

# Manual settings for configuring the network interface.
#
# These settings will be ignored if DHCP is enabled.
#
# Values: correctly-formatted IP address/subnet mask, e.g. AAA.BBB.CCC.DDD
#         (four numbers in the range 0-255 separated by periods)
ip_address = 192.168.1.100
subnet_mask = 255.255.255.0
default_gateway = 192.168.1.1
dns_server = 192.168.1.1

# Set the network hostname.
#
# Values: a valid hostname using ASCII letters 'a' to 'z', digits 0-9, and
#         hyphens (mt32-pi*)
hostname = mt32-pi

# Enable or disable the RTP-MIDI/AppleMIDI server.
#
# This allows you to send MIDI data to mt32-pi over the network using macOS'
# built-in network MIDI features, or rtpMIDI by Tobias Erichsen on Windows.
#
# Values: on*, off
rtp_midi = on

# Enable or disable the UDP MIDI server.
#
# This allows you to send MIDI data to mt32-pi via raw UDP socket on port 1999.
# Compatible with MiSTer MidiLink.
#
# Values: on*, off
udp_midi = on

# Enable or disable the embedded FTP server.
#
# This FTP server is a very basic implementation which DOES NOT feature any kind
# of transport layer security/encryption. Therefore, you should NOT enable this
# feature on a public network or expose the Raspberry Pi to the Internet.
#
# The FTP server should be considered a convenience feature only, for performing
# updates and configuration changes without having to replace the SD card.
#
# Values: on, off*
ftp = off

# Set the FTP server username and password.
#
# Values: any ASCII string (mt32-pi*)
ftp_username = mt32-pi
ftp_password = mt32-pi