VirtualMIDISynth (legacy 1.x series)

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WARNING: this version is not supported anymore.
Please upgrade to VirtualMIDISynth 2.


VirtualMIDISynth is a software MIDI synthesizer implemented as a Windows multimedia user driver, accessible as a standard MIDI Out device.

It works on Windows XP (SP3) / Vista (SP1) / 7 (SP1) / 8.x / 10 (both x86 and x64), and is based on the great BASS library from un4seen.

Brief intro

If you are a MIDI/karaoke fan like me, you know that MIDI play quality on Windows systems was not really good out of the box. The bundled "Microsoft GS Wavetable Synth" MIDI Out device is just... ehm... simple: poor samples, mono sound, no effects (reverb, chorus) support.

On 32bits systems some better alternatives exist, like the well-known YAMAHA XG SoftSynthetizer S-YXG50 and Cakewalk-sfz+ (both unsupported now).

Upgrading to an x64 system was a pain for me: S-YXG50 doesn't work at all, Cakewalk-sfz+ was unusable.

One day Ian Luck (un4seen) added to his BASSMidi library a great feature: the possibility to render a live MIDI stream, including SysEx messages. I quickly realized that, if only I could intercept that MIDI stream and drive it through Ian's library, well, we would have got a great MIDI Synth.

The challenge was to create a good quality synth and keep the end user away from complicated virtual MIDI chains (ever tried VanBasco -> MIDI Yoke/LoopBe1 -> SynthFont chain ?).

User only needs a new virtual MIDI Out device, select it as output on his preferred player settings and... start playing, nothing more.

Here we are, VirtualMIDISynth is the answer: an user mode multimedia x86/x64 driver that works on XP / Vista / 7 / 8 (both x86 and x64), implemented as a MIDI Out virtual device.

Screenshot 1

Main features

  • User mode multimedia driver, no reboots, no BSOD
  • Directly accessible as MIDI Out device, no need for virtual MIDI cables (like MIDI Yoke, LoopBe1)
  • MIDI mixer to set track mute/volume, accessible through systray icon while playing
  • Compact size (setup is ~900 KBytes)
  • No DLL cluttering, everything is self contained in System32/SysWOW64 subfolder
  • Clean installer, won't affect other MIDI devices
  • Efficient RAM usage (allows using large SoundFonts, > 1GByte)
  • Virtually unlimited polyphony (limited only by CPU)
  • Load up to 30 SoundFonts and chain them
  • Load all of your soundfonts into list and enable/disable them at your will
  • Configure MIDI Mapper default device (this feature is already available in XP, but missing in Vista / 7)
  • Multilanguage dialogs.
    If you want to help in translation, see here for status then get in touch to have access to the online translation system.

What now?

Well, having a better MIDI experience is easy as 1-2-3:

  • Download VirtualMIDISynth following the link you find at the bottom of this page and install it (you need administrative privileges)
  • Download a SoundFont (you'll find a list of free high quality files below) and add it to VirtualMIDISynt
  • Run your favourite MIDI application and configure it to use VirtualMIDISynt or, better, set VirtualMIDISynt as your default MIDI Out device (see screenshot below)
  • Donate to CoolSoft ;)
    oops, this step was not mandatory, anyway... thanks for doing it!

Maxime Abbey wrote a really detailed documentation on how to setup and configure VirtualMIDISynth; you can find it here.


Why are you still playing MIDI files? Have you ever heard of MP3?
Well, first because MIDIs are cool and compact; in a few megabytes you can store thousands songs.
Second, I love Karaoke; VanBasco is one of my preferred MIDI/KAR players.
Third, with MIDI you can silent some tracks, change tempo and pitch easily.

I tried playing a MIDI file on my PC, and it sucks!
I agree, that's why I wrote VirtualMIDISynth!
MIDI only contains "instructions" on what should be played: instruments, notes, their length, power and so on. It's up to the synthesizer to generate sound from these "commands".
The bundled Windows synthesizer, "Microsoft GS Wavetable Synth", is the worst.

Which players work with VirtualMIDISynt?
VirtualMIDISynt works with Windows Mediaplayer and MPlayer classic. Since these players cannot change their MIDI out device, you must set VirtualMIDISynt as your default device.
I suggest you to try VanBasco player, which is one of the best MIDI/KAR players around.

How much does it cost?
VirtualMIDISynt is freeware, you can use it as you like.

Why are you releasing it for free?
Because the greatest part of MIDI synthesis is done by BASS libraries from un4seen; I only wrapped them in a Windows driver and gave them an easy to use interface.

That's great, how can I thank you?
Send me a comment and tell about this software to your friends / forums / social networks.
You could also support its development with a donation.

Is there a tutorial available?
Don Allen wrote a great setup tutorial on MIDIKAR Yahoo group, freely available here.
That group is full of great MIDI experts and enthusiastics, please follow it.

--> See more FAQs here.Screenshot 1


VirtualMIDISynth is freeware, use it as you like.
Donations are welcome.


Here you'll find a list of some free and quality SoundFonts available on the net.
Please let me know if I miss something or if any link dies...

Some fonts are compressed with sfArk or sfPack.
This page contains links to decompressors:



  • Keppy's Steinway Piano
    Piano only soundfont by KaleidonKep99 (100Mb compressed, 350 uncompressed).
    WARNING: this SF is on GitHub, to download it click on "Releases".
  • Good list of soundfonts, suggested one is 084.0mg ALL In ONE GM V1.1 Bank.sf2
    (sorry, I can't read Japanese so I can't categorize its licensing)


  • Princess Soft SF2 (by Giovannino Imperi)
    NOTE: Soundfont author will devolve part of his donations to VirtualMIDISynth project.
    If you like this SF2, please let him him know you're a VirtualMIDISynth user.


If you're experiencing problems using VirtualMIDISynth, here's a list of common issues already solved.
Please check all of them before contacting me.


Links to sites that talk about us:

Version history 

v.1.17.1 - 2016-04-24

  • NEW: Added Arabic (Saudi Arabia) language, thanks to Abdullah Mohammad.

v.1.17.0 - 2016-03-29

  • NEW: New advanced option to enable sinc interpolated sample mixing instead of the default linear one.
    This increments sound quality but also CPU usage.
  • NEW: Added Comodo internet security to blacklisted processes.
  • NEW: Updated BASS to version and BASSMIDI to version
  • FIX: Fixed setup to properly update x64 driver dll when in use.

v.1.16.1 - 2016-03-03

  • NEW: Added Serbian (latin) language, thanks to Rastko.

v.1.16.0 - 2016-01-25

  • NEW: Added Thai language, thanks to suwisit.khlaewprayoon and rainny.ohm.
  • FIX: Uninstaller doesn't ask for language anymore but defaults to the one selected during installation.

v.1.15.2 - 2015-12-01

  • FIX: Updated BASS.dll to and BASSMIDI.dll to
  • FIX: Fixed setup build procedure to include the correct BASS* versions.

v.1.15.1 - 2015-11-09

  • FIX: Untranslated strings will fallback to English again (1.15.0 regression).
  • FIX: Completed Spanish translation (thanks to Juan López).

v.1.15.0 - 2015-09-28

v.1.14.1 - 2015-09-17

  • FIX: Updated BASS.dll to and BASSMIDI.dll to to fix crashes in some games (like Simutrans 120.0.1).

v.1.14.0 - 2015-09-16

  • NEW: Added Traditional Chinese (Taiwan) language, thanks to CW Wang.
  • NEW: Driver will now show an error if one or more SF failed to load.
  • FIX: Fixed SF preload error message.
  • FIX: Updated translations.
  • FIX: Fixed x64 pointers in x64 build, leading some programs (like TeamSpeak Client 3 and possibly other x64 MIDI players) to crash under Win8.1 and Win10.

v.1.13.2 - 2015-05-03

  • FIX: Setup missed the BassMidi library update.

v.1.13.1 - 2015-05-02

  • NEW: Configurator and Mixer dialogs now can be snapped to all other windows.
  • NEW: Added Brazilian Portuguese language support (thanks to Carlos Eduardo).
  • NEW: BassMidi library updated to version that improves MIDI rendering.
  • FIX: Setup now correctly detects WinXP-x64 and won't require SP3 for it.

v.1.13.0 - 2015-03-29

  • NEW: Added "reset/mute all/unmute all" features to MIDI Mixer. Right click over the MIDI Mixer to show the new popup menu.
  • NEW: Setup now detects x64 processes locking files being installed/updated.
  • NEW: Updated BASS to 2.4.11 and BASSMIDI to 2.4.9.
  • NEW: Added turkish language (thanks to Hakan ATEŞ).
  • FIX: Crash when driver is opened and closed quickly, before initialization completes.

v.1.12.1 - 2015-01-07

  • NEW: Added Finnish language support (thanks to Jussi Bergström).
  • FIX: Crash when driver is opened and closed quickly, before initialization completes.

v.1.12.0 - 2014-10-31

  • NEW: MIDI Mixer and configurator dialogs now "snap" to desktop borders when moved (press SHIFT while moving to disable snap).
  • FIX: Rewritten and optimized driver dialogs handling to avoid MIDI client hangs and memory leaks (1.11.0 regression).
  • FIX: Fixed hangs and crashes on x64 systems.

v.1.11.0 - 2014-10-11

  • NEW: Added Chinese (simplified) language support (thanks to Magsom).
  • NEW: Updated BASSMIDI to version
  • NEW: Added support to 22050Hz output frequency.
  • NEW: Max simultaneous MIDI voices limit (polyphony) increased to 1000.
  • FIX: Some MIDI clients hang on close (mostly games emulators, like eduke32).

v.1.10.1 - 2014-07-06

  • FIX: An installer bug prevents installation on systems where VirtualMIDISynth has never been installed.

v.1.10.0 - 2014-07-04

  • NEW: Added support for MIDI running status.
  • FIX: Wrong parsing of MIDI System Real Time Messages.

v.1.9.2 - 2014-06-20

  • NEW: Added Korean language support (thanks to heocurly)

v.1.9.1 - 2014-05-15

  • NEW: Updated BASSMIDI to, now supports these SF2 parameters (see here for details:
    + Keynum to hold (for Volume & Modulation envelope)
    + Keynum to decay (for Volume & Modulation envelope)
    + Fixed key
    + Fixed velocity
    (thanks to kinwie for reporting and testing)

v.1.9.0 - 2014-04-10

  • NEW: Configurator settings for Reverb & Chorus effects level.
  • NEW: Configurator setting to override Reverb & Chorus SYSEXes received from MIDI (and force our custom levels).
  • NEW: Updated BASS to version 2.4.10 and BASSMIDI to 2.4.8
  • NEW: Added Magyar language support (thanks to Nádasdi Zsolt)
  • NEW: New setup commandline option "/skip_os_check" to let it run on misdetected systems.

v.1.8.2 - 2013-11-10

  • NEW: Added Dutch language (thanks to Tim Hoekstra)
  • FIX: Some errors message were not shown with full detail
  • FIX: Windows Media Player default device MIDI setting doesn't create keys correctly
  • FIX: Improved OS detection during setup
  • FIX: Improved detection of other VirtualMIDISynth instances

v.1.8.1 - 2013-04-22

  • NEW: Added Portuguese (Portugal) language (thanks to Gonçalo Ferreira)
  • FIX: Fixed a bug with DosBox (and maybe other MIDI Clients) that caused crashes and hangs during play
    (many thanks to "drivetheory": sending me saved games and instructions on how to reproduce the bug was a great help, really appreciated)

v.1.8.0 - 2013-03-30

  • NEW: Added Windows Media Player default MIDI device setting (see here for details)
  • NEW: Vietnamese language (thanks to MyNa VN)
  • NEW: Danish language (thanks to Heine Svendsen)
  • NEW: Czech language (thanks to Vaclav Muller)
  • NEW: Improved update checker messages
  • FIX: Clicking on hotkey balloon error will now open the configurator shortcut keys tab
  • FIX: Hotkey balloon error will now show the shortcut that can't be created

v.1.7.0 - 2013-02-07

  • NEW: Polish language (thanks to SuperGod)
  • NEW: Indonesian language (thanks to Latiful)
  • NEW: Swedish language (thanks to Magnus Johansson)
  • NEW: Added support for GM/GM2/GS/XG instrument names, now correctly shown on MIDI Mixer
  • NEW: Added an activity indicator on each MIDI channel, useful to quickly see which channel is actually playing
  • NEW: MIDI Mixer can now be moved by clicking (and dragging) anywhere on it
  • NEW: Added support for MIDI running status bit (some players call it "redundant MIDI data")
  • FIX: Fixed a small memory leak in Mixer drawing functions

v.1.6.3 - 2013-01-10

  • NEW: German language (thanks to Markus Stein)

v.1.6.2 - 2012-11-24

  • NEW: Japanese language (thanks to yukinodsyouid)

v.1.6.1 - 2012-11-01

  • NEW: Russian language (thanks to Boris Petrov)
  • NEW: French language (thanks to Aziz Lallouche)
  • NEW: Spanish language (thanks to Pedro López-Cabanillas)
  • FIX: Fixed BASS initialization in case of already initialized BASS library
  • FIX: Language files are now UTF-8
  • FIX: Better language file memory management
  • FIX: Soundfont listbox doesn't enable Apply button on checkboxes state changes

v.1.6.0 - 2012-10-21
VirtualMIDISynth is now multilanguage, English and Italian for now.
Dialogs and messages can be easily translated into other languages. If you like to help
in translating VirtualMIDISynth into your native language please get in touch at

  • NEW: Multilanguage setup, UI dialogs and messages
  • NEW: Option to select language into configurator
  • NEW: Configurator Soundfont chain list items now have a checkbox to allow disabling them while keeping on the list
  • FIX: Increased soundfont list count limit to 30 elements
  • FIX: Increased configurator dialog width to better accomodate translated strings
  • FIX: Added accelerator keys to dialogs

v.1.5.0 - 2012-09-29
Most of VirtualMIDISynth features can now be controlled by PC keyboard.

  • NEW: MIDI Mixer keyboard shortcuts:
    (selected channel has its number underlined)
    LEFT/RIGHT => move selection to left/right
    0          => select master channel
    1..9       => select channel 1...9
    CTRL+0..6  => select channel 10...16
    UP/DOWN    => increase/decrease channel volume
    HOME/END   => quick set volume to max/min
    M          => toggle mute state
  • NEW: VirtualMIDISynth keyboard shortcuts:
    CTRL+ALT+M       => show/hide MIDI Mixer
    CTRL+ALT+SPACE => MIDI panic (note off to all MIDI channels)
  • NEW: Increased max notes limit to 500
  • NEW: Updated BASS library to version
  • NEW: Updated BASSMIDI library to version
  • FIX: Optimized MIDI Mixer memory usage

v.1.4.0 - 2012-07-20
Lot of new features and fixes in this (long waited) first release of the 1.4.x series.


  • NEW: Added support for 64bit MIDI client applications (on 64bit OS)
  • NEW: Better compatibility with BASS based MIDI clients, like Karafun and Synthesia
  • NEW: Default systray context menu item is now mixer which can be opened by double clicking icon
  • FIX: Increased sound buffer efficiency and better threads management


  • NEW: Rewritten configurator with a new tabbed interface; now it could contain the new options in a more clean GUI
  • NEW: Lot of new settings added:
    • "advanced" settings to reduce CPU requirements disabling some features (like effects, polyphony, ...)
    • output audio device selection
    • automatically open MIDI Mixer while playing
    • raise MIDI player process priority to "High priority"
    • enabling audio hardware mixing
    • audio output buffer size (default 250ms)
  • NEW: Option to preload the whole soundfont file into memory before play (enabled by default). It increases the required memory and adds a small delay at start, but also gives a smoothest play because samples are already available in memory.
  • NEW: Horizontal scrollbar into soundfont list to allow reading long filenames.


  • NEW: Better loking mixer VUMeter bar, it now appears like a LED stripe
  • NEW: Mixer level meter now shows the running average of output level instead of the instant value, making it more realistic and "analogic"
  • NEW: Increased channel name font size and enabled cleartype drawing

v.1.3.1 - 2011-12-10

  • NEW: Post setup actions are not preselected by default.
    "Show readme.txt" option has been removed and this file is now shown during into setup (while still available through Start menu link).
    "Run configurator" and "Open website" checkboxes are blanked if a SoundFont is already configured.
    Clickthrough users should now be happier during updates.
  • FIX: Fixed updater code causing VirtualMIDISynth device to disappear on some localized WinXP versions.
    (thanks to user "exit" from kvraudio forum who helped pointing out compatibility issues under his localized XP)

v.1.3.0 - 2011-10-25

  • NEW: Added update check feature; you can configure VirtualMIDISynth to automatically check if an updated version is available.
    Default check frequency is 14 days (can be changed with configurator). If an update is available, a balloon notification appears on systray when VirtualMIDISynth is loaded (but no more than once a day).
  • NEW: Mixer window position is now clipped to the nearest screen, avoiding it to open out of screen when switching from dual-screen config to single.
  • NEW: Updated bassmidi.dll to version 2.4.8.
  • FIX: Fixed an important memory leak on Mixer window that causes hosting process memory to continuously increase when the Mixer is shown.
  • FIX: MidiMapper now creates the whole registry path if not exists.
  • FIX: Configurator now checks if another instance is running.


WARNING: this version is not supported anymore.
Please upgrade to VirtualMIDISynth 2.


Latest stable version included languages: English, Italian, French, Spanish, German, Greek, Portuguese (Portugal), Portuguese (Brazil), Russian, Japanese, Polish, Swedish, Finnish, Danish, Indonesian, Vietnamese, Czech, Dutch, Magyar, Chinese (simplified), Chinese Traditional (Taiwan), Korean, Turkish, Serbian (latin), Arabic (Saudi Arabia).
If you want to help in translation, VirtualMIDISynth has an on-line translation system that's really easy to use: see here for current language status then get in touch, I'll create a "translator" account (or allow your existing account to access the translation system) and you're ready to go.

VirtualMIDISynth automatically notifies its updates (if enabled), otherwise you can subscribe here to be notified.

Beta versions are announced in the announcements forum; please subscribe there to be notified.

Description Latest version (unsupported, upgrade to version 2.x)
Release date 2016-Apr-24 Size 1,028,570 bytes
MD5 63de0cab255280745d2c4b2cc829807b
SHA1 75fe0be4ae250bbd1e4abf134745a88030f163c1
SHA256 fa2d535cff135b6ab419ac0d00998fc9541e62b420f11c9e0d1e644508447203
Open virus check report