Connecting a MIDI Synthesizer to a Windows 10 computer

Just bought your first old school MIDI synthesizer and can't get it to work right? Having trouble getting DOSBox or SCUMMVM to work the way you want? Perhaps we can help. Do you have some neat tips you just want to share with the world? Or maybe you just need help convincing your computer to work. Either way, use this forum for all tech support related needs that somehow relate to MIDI and/or PC Gaming.

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Connecting a MIDI Synthesizer to a Windows 10 computer

Post by Alderem »

Seven years ago, I got a new computer which didn't have a joystick port. My MT-32 has sat nearby, unused, ever since. Recently I decided to do something about it.

Here's the steps, if you care to follow. This addresses playback of MIDI files from this site, but some steps may be applicable to getting old games to work as well (future tutorial, perhaps?).

You'll need:
  1. A working external MIDI synth, such as a Roland MT-32 or Sound Canvas or such. If you don't have one of those, you don't need to do this.
  2. A computer with USB type-A port, a LINE IN audio port, and current Windows OS (10).
  3. USB to MIDI cable. I purchased the Roland UM-ONE-mk2 cable for about $40. Do not pay more. There are much cheaper cables out there, but they may not be reliable, and not all versions support SysEx (System Exclusive) messages which you'll want if you're playing back many of the files available here at The QuestStudios Archive. Steps below will assume you're using the Roland cable.
  4. Audio cables to route the synth's output back to the LINE IN input of your computer (NOT MICROPHONE), unless you want to set up another set of speakers. This typically involves converting from stereo RCA plugs (red and white, on the synth) to a 3.5mm plug (for your computer).
  5. (Recommended) Audio Ground Loop Isolator cable. This removes hum from your synth output as you loop it back to your computer. I have one with RCA plugs, from Radio Shack, back when Radio Shack was a thing.
  6. Patience and willingness to fight with Microsoft's infernal software and choices
  1. USB to MIDI cable: If you purchased the Roland cable, and you're on Win 10 as mentioned above, you shouldn't need the included CD. The device is plug and play. It also shouldn't matter if you have the cable set to COMP(uter) or TAB(let), but you might set it to COMP just in case. USB end is straightforward - at the MIDI end, ensure that you connect the cables to your synth correctly. Rather than using confusing words like "MIDI IN" and "MIDI OUT" like cables of old, leaving it to you to figure out that CABLE MIDI OUT = DEVICE MIDI IN, the Roland cable has helpful embossed arrows. If the arrows point towards the end you'd expect to plug in somewhere, that goes into MIDI IN on your synth. If they point back towards the controller, you've got the wrong plug. Plug in the USB side while your computer is powered on, and you'll get a red light at the controller mid-cable to let you know it's getting the necessary power and USB connectivity. You can also verify that the device has been found in Windows by typing "Device Manager" into the search bar, opening that app, expanding "Sound, video, and game controllers" in the list, and verifying that UM-ONE is there.
  2. MIDI Mapper: Sometime in the past 7 years, Microsoft decided to rip the MIDI Mapper out of their operating system.
    Everything goes to "Microsoft GS Wavesynth" now. You'll want to download and install Coolsoft MidiMapper, the most well-regarded on the internet, and it has been updated to v1.1 as recently as September 2019. The website has an obnoxious anti-ad-blocker, so if you have an adblocker, you'll need to turn it off for this site. Since the software is free and works, I couldn't complain. Run the MIDI Mapper, and change from Wavetable to UM-ONE. Click Apply.
  3. MIDI Player: Along with the MIDI mapper, Microsoft threw out the MIDI player. VLC won't let you play to an external device. Windows Media Player, which is still bundled with the OS, will work and it can send SysEx. Set your default MIDI file player to WMP (or another program you know that works, if you prefer).
  4. Line In Audio: The last piece is to ensure Line In Audio will work. Yours might be configured correctly, mine wasn't. Various panels in Windows may cheerfully tell you that Line In is Enabled, or at least that it isn't Disabled, but you might still not get sound. There are multiple ways to get to the necessary level of purgatory within Microsoft's menus, but the fastest is to follow the instructions I found at to type mmsys.cpl into the search bar, open up the app that appears, select the Recording tab, scroll down to Line In and select it, click Properties, click the Listen tab, and check the box that says "Listen to this device", because of course that's a sane place to hide a setting that makes your enabled device behave as though it isn't enabled. (If "Line In" isn't in your list at all, follow the bleepingcomputer article to see if the further advice there helps.)
If all is well, this will enable you to play MIDI files to your external synth. If you need to troubleshoot further there are a few things to try:
  • The Roland UM-ONE cable has additional lights that indicate if data is being transmitted from MIDI IN or to MIDI OUT. The OUT light should flicker when you're playing a MIDI stream successfully. If it's not flashing, make sure you're sending data to the UM-ONE and not to the built in Wavesynth. Windows may sometimes switch back to the Wavesynth if you unplug anything.
  • On the front of your synth, there should be some indication if it's receiving data. If it isn't receiving, double check that the plug with the arrows flowing away from your computer and towards your device is the one plugged into MIDI IN on your device.
  • If everything's flashing but you don't hear anything, try running audio directly from the synth to your speakers without going through the computer's Line In. If this succeeds in producing sound, you'll at least know the problem is in the Line In driver settings.
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Re: Connecting a MIDI Synthesizer to a Windows 10 computer

Post by jaffa225man »

Thanks Martin! That was quite an enjoyable read for someone with similar windows sensibilities. I should write up something similar to what I did to get Line-In live monitoring working on GNU/Linux (using a pulse audio sink, if memory serves). MIDI mapping, thankfully, is still the same on GNU/Linux as it always was, well since ALSA arrived anyway... but even so the common method is through the command line :)
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