Real-time Interfacing of VST Instrument Libraries with MuseScore using a Digital Audio Workstation

If you do not already know how to use a digital audio workstation or DAW, this How-To guide is not for you. This guide is meant for MuseScore users who already compose and produce music using a DAW, and who might want to experiment with connecting MuseScore to their DAW.

MuseScore has the ability to connect in real time to a digital audio workstation (DAW) and associated high quality instrument sample libraries (sometimes known as VSTs). This allows for real time MuseScore composition and playback using more realistic sounding instruments. This guide is not about exporting a MuseScore composition to midi or XML and then importing that into a DAW, rather this guide is about composing in MuseScore in real-time, and playing back a MuseScore composition or part of a composition in real-time using the much more realistic sounds that a DAW can utilize. Finalize, expect this method to be a little buggy, perhaps a little difficult for some, but if you want to give this a try here is a guide that can work. In the end, you might decide the best way to use MuseScore is simply to use MuseScore’s soundfonts, its default set of built in synthetic instrument sounds.

https://player.vimeo.com/video/401736765 (no longer available)

This guide is not a guide to using a DAW. It is assumed the reader of this guide already has a good working knowledge of using their DAW, including how to install, load, and configure VST instruments, and how to set up multiple tracks in a DAW.

In this guide, Reaper will be used for the DAW though just about any DAW should be able to do this following the same basic steps. Reaper as a DAW is very affordable and includes a 60 day evaluation license if you want to give this a try without any extra financial commitment.
https://www.reaper.fm/

Native Instruments also has a completely free ‘KOMPLETE Start’ set of instrument sample libraries (VSTs) as well as a free KONTAKT VST player.
https://www.native-instruments.com/en/products/komplete/bundles/komplet…

There are many other free sample libraries available on the internet. If you already own a DAW, you probably already have your own selection of VST sample libraries that you use regularly.

One warning-- if you use Spitfireaudio’s LABS instruments (high quality, free), note that if you pause playback they will continue to sound and the only way to stop them is to temporarily toggle off their track(s) record monitoring. Also be sure to set the midi channel for each LABS instrument to 1,2,3 and so on to match the MuseScore instrument channel.

STEP 1: Download and install loopMIDI, a free virtual midi port.
https://www.tobias-erichsen.de/software/loopmidi.html

STEP 2: Download and install ASIO4ALL, unless you already have some other sound driver that works. This tutorial how-to will make use of ASIO4ALL which is completely free. http://www.asio4all.org/

STEP 3: Probably best to reboot your computer after installing both loopMIDI and ASIO4ALL. Then be sure to set you audio device in both MuseScore and your DAW (Reaper, etc) to ASIO4ALL. In MuseScore you can do this in Edit->Preferences->I/O. In Reaper you do this in Options->Preferences->Audio->Device->ASIO Driver. Then close both MuseScore and your DAW.

STEP 4: MuseScore. Set up a simple score with perhaps 3 staves (instruments), it really does not matter what you call them or what instruments they are because you will not be using MuseScore's soundfonts (synthesized instruments), but you can match MuseScore instrument sounds with those you set up in your DAW if you wish, just for clarity. Now for each instrument or stave in MuseScore, look at the Mixer (F10) and make sure your instrument staves (tracks) use channel 1 for the top instrument stave, channel 2 for the second stave, channel 3 for the third stave, and so on. Now you can input notes into MuseScore unless you already have a composition loaded in MuseScore (in fact, once you complete the pairing of MuseScore with your DAW, you will hear your DAW's instrument notes as you add/edit notes in MuseScore). The channels in MuseScore will correspond to the tracks (top to bottom in the DAW).

Here is the Musescore (version 3) composition file used for the screenshots in this guide. Feel at liberty to use, reuse, and share the short four-bars composition.
MuseScore_+_DAW.mscz

Step 5: MuseScore. Edit->Preferences->I/O, set the Audio output device to ASIO4ALL if not already done, and set the MIDI output to loopMIDI.

Step 6: DAW (Reaper). Options->Preferences->Audio->MIDI Devices, be sure to toggle on (disabled to enabled) the midi device loopMIDI.

Step 7: DAW (Reaper). Load your tracks in your DAW and set up whatever VST instruments you want for your tracks. The DAW tracks top to bottom will correspond to your MuseScore channels, in the same order. If you have a MuseScore instrument (stave) set as channel 3 then that will pair with the third track from the top in your DAW.

For each instrument (VST) in your DAW, make sure to set the VST (not the track input) to port A (port 1) and to OMNI for the VST channel.

For the tracks in your DAW, set their inputs to input MIDI loopMIDI channel 1 for the first stave (channel 1) in MuseScore, channel 2 for the second stave (channel 2) in MuseScore, and so on. Each track should have input monitoring turned on, and record armed (far left button on a track in Reaper).

Step 8: Dual Audio. MuseScore is probably set up to play through your desktop computer or laptop external speakers, so you will want to turn their volume down to zero so MuseScore soundfont playback does not interfere with the high quality VST sampled instruments playback from your DAW. Or, in the MuseScore Mixer, you can just turn the master volume slider control down to zero volume ouput.

In your DAW, open ASIO4ALL (in Reaper, you can click the ASIO4ALL link in the far upper right corner of Reaper) and set the audio output device to e.g. your desktop monitor's audio, or some other available audio device (e.g. if you choose audio output from your DAW to your desktop monitor, then plug headphones into your monitor's headphone port/jack and use your headphones to listen to playback now of your MuseScore composition.

If you want to hear your DAW's output to your higher quality desktop external speakers, you can always set MuseScore to output ASIO4ALL audio to your secondary audio device (such as your computer screen monitor's audio headphones output or its less than optimal built in speakers), and then set your DAW to send ASIO4ALL audio output to your desktop external speakers.

RECORDING
If you want to record MIDI in your DAW's tracks, just press your DAW's record button then press the Play button in MuseScore. Your MuseScore composition will play, and the midi notes will be recorded in your DAW's tracks (as long as each track has its arm record button toggled on of course). After the MuseScore composition has completed playback, press the Stop button in your DAW's playback controls.

TROUBLESHOOTING:
If you do not hear audio, make sure that MuseScore and your DAW are not sharing the same audio output device, that your headphones are correctly plugged into your computer monitor's headphone port and not a microphone port, that your DAW's tracks each have both the record button armed and the monitoring button turned on, that each track in your DAW is set to receive midi input from the loopMIDI channel number that matches the desired MuseScore stave's channel, and that in e.g. Kontakt that an instrument (VST) is set to receive midi from OMNI (not from any specific individual channel).

If all else fails, you might need to restart your computer, because an operating system might get confused with the midi outputs and inputs and virtual midi ports.

NOTE: VST3 instruments are now fully compatible with MuseScore 4.