How To Actually Connect An External MIDI Device

26Oct/180

How To Actually Connect An External MIDI Device

I started this journey thinking that MIDI cables were really simple. There's a joystick-style plug at one end and two DIN-5s at the other for MIDI-OUT and MIDI-IN. MIDI output from the computer comes out the OUT cable and MIDI you're receiving from elsewhere comes into the computer on the IN cable.

So, when you're hooking up an external module, like this MT-100, you simply connect them up...

There they go, OUT to IN and IN to OUT. Right? You want the output from the PC (be that the soundtrack of a game) to go into the Synth/Module to be processed. Like so... I don't really care about the module output at this point, but for-neatness-sake, let's plug it in!

IT TURNS OUT YOU DON'T WANT TO DO THIS. You're actually creating a loop and the MIDI data will come straight back out of the module and into the PC. This will then cause all matter of DMA/IRQ interrupts and you'll probably freeze your machine. I've actually just spent the greater part of two nights having DOOM II lock up every time I set both SB16 and MIDI-OUT. I went through all matter of IRQ or DMA settings, thinking the combination of a SCSI card, Network card and Sound card were fighting. After a quick google of vogons, I realised that the machine was freezing/slowing-down/locking-up due to the rebounding MIDI data!

This article was actually going to be titled 'DOOM II Freezes when selecting SB16 and MIDI-OUT'. Either way, do this instead... connect OUT (from the PC) to IN (on the module)...