DOSBox-X Audio and MIDI Hardware Configuration Guide

DOSBox-X emulates a rich set of DOS-era audio hardware. The [mixer] section governs the global audio pipeline; [midi] controls MIDI output including MT-32 and FluidSynth; [sblaster] emulates Creative Sound Blaster cards with AdLib/OPL; [gus] emulates the Gravis UltraSound; and [speaker] covers the PC speaker, Tandy 3-voice, and Disney Sound Source. Configuring these correctly is often the difference between silence and authentic DOS audio.

`[mixer]` — Global audio pipeline

The mixer controls the combined audio output that all emulated sound devices feed into.

nosound

bool

default:"false"

Run DOSBox-X in silent mode. Sound hardware is still emulated and programs behave normally, but no audio is sent to the host. Useful for automated testing or when running headless.

rate

integer

default:"48000"

Host audio sample rate in Hz. All emulated devices will be resampled to this rate. Higher rates improve fidelity but increase CPU usage.Valid values: 8000, 11025, 16000, 22050, 32000, 44100, 48000, 96000, 192000

rate = 48000

blocksize

integer

default:"1024"

Audio buffer block size in samples. Larger blocks reduce the risk of audio dropouts on slower or heavily loaded systems but increase latency.Valid values: 256, 512, 1024, 2048, 4096, 8192

prebuffer

integer

default:"25"

Milliseconds of audio data to buffer on top of blocksize before playback begins. Increase this value if you hear stuttering or crackling.

The sample accurate option (default false) enables sample-accurate mixing at the cost of some CPU. Enable it for demos or games that require precise Tandy/OPL timing, such as those using digitized speech through OPL tricks.

`[midi]` — MIDI output and synthesis

mididevice

string

default:"default"

The device or synthesizer that receives MIDI data from DOSBox-X’s MPU-401 emulation.

Value	Description
`default`	Use the OS default MIDI output
`win32`	Windows MM MIDI output (specify device with `midiconfig`)
`alsa`	ALSA sequencer (Linux; specify port with `midiconfig`)
`oss`	OSS MIDI (Linux)
`coreaudio`	macOS CoreAudio synthesizer (optionally specify a soundfont via `midiconfig`)
`coremidi`	macOS CoreMIDI output port
`synth`	Internal software synthesizer (specify a soundfont via `midiconfig`)
`mt32`	MT-32 emulation via Munt (requires ROM files)
`fluidsynth`	FluidSynth software synthesizer (requires SF2 soundfont)
`timidity`	TiMidity++ soft synth
`none`	Disable MIDI output entirely

mididevice = fluidsynth

midiconfig

string

default:""

Device-specific configuration string. For win32, specify a Windows MIDI device ID or part of its name. For alsa, specify the ALSA port (e.g. 128:0). For coreaudio or synth, you can specify a soundfont path here instead of using fluid.soundfont.

midiconfig = 2 delaysysex

MT-32 emulation

DOSBox-X includes Munt-based MT-32 emulation. You must provide your own ROM files (legally obtained from a real MT-32 unit).

mt32.romdir

string

default:""

Directory containing the MT-32 Control and PCM ROM files. DOSBox-X looks for files named MT32_CONTROL.ROM and MT32_PCM.ROM (or their CM-32L equivalents).

mt32.romdir = ~/roms/mt32

mt32.model

string

default:"auto"

Model of MT-32 synthesizer to emulate.

Value	Description
`auto`	Automatically select based on available ROM files
`mt32`	Emulate the original Roland MT-32
`cm32l`	Emulate the Roland CM-32L (superset of MT-32)

FluidSynth settings

fluid.soundfont

string

default:""

Path to an SF2 or SF3 soundfont file for FluidSynth. This is required when mididevice = fluidsynth. Popular free soundfonts include GeneralUser GS and FluidR3 GM.

fluid.soundfont = /usr/share/sounds/sf2/FluidR3_GM.sf2

fluid.gain

float

default:"(FluidSynth default)"

FluidSynth synthesizer output gain (0.0 to 10.0). The default FluidSynth gain is used if not set. Reduce this if FluidSynth output is clipping against other audio sources.

fluid.gain = 0.5

FluidSynth example

[midi]
mididevice      = fluidsynth
fluid.soundfont = /path/to/FluidR3_GM.sf2
fluid.gain      = 0.6

`[sblaster]` — Sound Blaster emulation

DOSBox-X emulates the full Creative Sound Blaster family, from the original SB1.0 through to the SB16.

sbtype

string

default:"sb16"

The Sound Blaster model to emulate.

Value	Card emulated
`sb1` / `sb1.0` / `sb1.5`	Sound Blaster 1.x
`sb2` / `sb2.0` / `sb2.01`	Sound Blaster 2.0
`sbpro1`	Sound Blaster Pro (OPL2 stereo)
`sbpro2`	Sound Blaster Pro 2 (OPL3)
`sb16`	Sound Blaster 16 (most compatible, default)
`sb16vibra`	Sound Blaster 16 Vibra variant
`ess688` / `ess1688`	ESS Technology ES688/ES1688
`reveal_sc400`	Reveal SC400
`gb`	Game Blaster (CMS)
`none`	Disable Sound Blaster emulation

sbtype = sb16

sbbase

hex

default:"220"

I/O base address of the Sound Blaster.Valid values: 220, 240, 260, 280, 2a0, 2c0, 2e0Most DOS games expect the default of 220h.

irq

integer

default:"7"

IRQ number for the Sound Blaster.Valid values: 3, 5, 7, 9, 10, 11, 12IRQ 7 is the most commonly expected value; some games default to IRQ 5.

dma

integer

default:"1"

Low DMA channel for 8-bit audio transfers.Valid values: 0, 1, 3, 5, 6, 7

hdma

integer

default:"5"

High DMA channel for 16-bit audio transfers (SB16 only).Valid values: 0, 1, 3, 5, 6, 7

OPL / AdLib settings

oplmode

string

default:"auto"

Type of OPL chip to emulate. On auto, the mode is determined by the sbtype setting.

Value	Description
`auto`	Choose based on `sbtype`
`opl2`	OPL2 (AdLib compatible, mono)
`dualopl2`	Dual OPL2 (SB Pro stereo)
`opl3`	OPL3 (YMF262, stereo)
`opl3gold`	OPL3 Gold variant
`esfm`	ESS FM (ESS Technology variant)
`none`	Disable OPL emulation
`hardware` / `hardwaregb`	Pass through to real OPL hardware

oplemu

string

default:"default"

OPL emulation provider.

Value	Notes
`default`	DOSBox-X built-in emulator
`compat`	May provide better quality for some titles
`nuked`	Most accurate, most CPU-intensive
`fast`	Fastest, least accurate
`mame`	MAME OPL core

oplrate

integer

default:"49716"

OPL chip sample rate. Use 49716 for the highest quality (and set mixer rate to match).Valid values: 8000, 11025, 16000, 22050, 32000, 44100, 49716

Sound Blaster quick-reference

[sblaster]
sbtype  = sb16
sbbase  = 220
irq     = 7
dma     = 1
hdma    = 5
oplmode = auto
oplemu  = nuked
oplrate = 49716

`[gus]` — Gravis UltraSound

gus

bool

default:"false"

Enable Gravis UltraSound emulation. Must be true for any GUS settings to have effect.

gustype

string

default:"classic"

GUS hardware variant to emulate.

Value	Card
`classic`	Original GUS chipset
`classic37`	Original GUS with ICS Mixer (rev 3.7)
`max`	GUS MAX (with CS4231 codec)
`interwave`	GUS Plug & Play (InterWave)

gusbase

hex

default:"240"

GUS I/O base address. Valid values: 210, 220, 230, 240, 250, 260, 280, 2a0, 2c0, 2e0, 300

gusirq

integer

default:"5"

GUS IRQ. Valid values: 3, 5, 7, 9, 10, 11, 12

gusdma

integer

default:"3"

GUS DMA channel. Valid values: 0, 1, 3, 5, 6, 7

gusmemsize

integer

default:"-1"

GUS RAM size in KB. Set to -1 for the default amount appropriate to the selected gustype.

ultradir

string

default:"C:\\ULTRASND"

Path to the Ultrasound directory. This directory should contain a MIDI subfolder with GUS patch files. Patch sets for TiMidity++ are compatible.

`[speaker]` — PC speaker and simple sound

pcspeaker

bool

default:"true"

Enable PC speaker emulation. The PC speaker is used for simple beeps and sound effects in many early DOS games and BIOS alerts.

pcrate

integer

default:"65536"

Sample rate for PC speaker synthesis.Valid values: 8000, 11025, 16000, 22050, 32000, 44100, 48000, 49716, 65536

tandy

string

default:"auto"

Enable Tandy 3-voice sound emulation.

Value	Behaviour
`auto`	Enable only when `machine=tandy`
`on`	Always enable Tandy sound
`off`	Always disable Tandy sound

tandyrate

integer

default:"48000"

Tandy 3-voice synthesis sample rate.Valid values: 8000, 11025, 16000, 22050, 32000, 44100, 48000, 49716

disney

bool

default:"false"

Enable Disney Sound Source emulation (also compatible with the Covox Voice Master and Speech Thing). Connects to the parallel port.

`[innova]` — Innovation SSI-2001

The SSI-2001 was an ISA sound card built around the MOS 6581 SID chip (the same chip used in the Commodore 64).

innova

bool

default:"false"

Enable Innovation SSI-2001 emulation.

sidbase

hex

default:"280"

SID chip base I/O port. Valid values: 220, 240, 260, 280, 2a0, 2c0, 2e0, 300

quality

integer

default:"0"

SID emulation quality level (0–3). Higher values are more accurate but use more CPU.

Audio configuration examples

Standard DOS gaming
FluidSynth MIDI
MT-32 games
Tandy / PCjr

Sound Blaster 16 with high-quality OPL emulation — the best choice for the vast majority of DOS games.

[mixer]
rate      = 48000
blocksize = 1024
prebuffer = 25

[sblaster]
sbtype  = sb16
sbbase  = 220
irq     = 7
dma     = 1
hdma    = 5
oplmode = auto
oplemu  = nuked
oplrate = 49716

Use a GM soundfont for high-quality General MIDI music alongside Sound Blaster digital audio.

[midi]
mididevice      = fluidsynth
fluid.soundfont = /usr/share/sounds/sf2/FluidR3_GM.sf2
fluid.gain      = 0.6

[sblaster]
sbtype = sb16

For Sierra On-Line and other MT-32-era games. Requires ROM files.

[midi]
mididevice  = mt32
mt32.romdir = ~/roms/mt32
mt32.model  = auto

Enable Tandy 3-voice sound for PCjr or Tandy machine types.

[dosbox]
machine = tandy

[speaker]
tandy     = auto
tandyrate = 48000
pcspeaker = true

If you experience audio dropouts or crackling, try increasing blocksize to 2048 or 4096 and prebuffer to 50. On systems with low latency audio drivers you can safely reduce these values.

Getting Started

Configuration

Drives & Storage

Emulation Features

Troubleshooting

DOSBox-X Audio and MIDI Hardware Configuration Guide

`[mixer]` — Global audio pipeline

`[midi]` — MIDI output and synthesis

MT-32 emulation

FluidSynth settings

FluidSynth example

`[sblaster]` — Sound Blaster emulation

OPL / AdLib settings

Sound Blaster quick-reference

`[gus]` — Gravis UltraSound

`[speaker]` — PC speaker and simple sound

`[innova]` — Innovation SSI-2001

Audio configuration examples

Build docs developers (and LLMs) love

Getting Started

Configuration

Drives & Storage

Emulation Features

Troubleshooting

Documentation Index

​[mixer] — Global audio pipeline

​[midi] — MIDI output and synthesis

​MT-32 emulation

​FluidSynth settings

​FluidSynth example

​[sblaster] — Sound Blaster emulation

​OPL / AdLib settings

​Sound Blaster quick-reference

​[gus] — Gravis UltraSound

​[speaker] — PC speaker and simple sound

​[innova] — Innovation SSI-2001

​Audio configuration examples

Build docs developers (and LLMs) love

`[mixer]` — Global audio pipeline

`[midi]` — MIDI output and synthesis

MT-32 emulation

FluidSynth settings

FluidSynth example

`[sblaster]` — Sound Blaster emulation

OPL / AdLib settings

Sound Blaster quick-reference

`[gus]` — Gravis UltraSound

`[speaker]` — PC speaker and simple sound

`[innova]` — Innovation SSI-2001

Audio configuration examples