Hello everyone, this is my first time here so nice to meet you all!

I come to you looking for your expertise. I am relatively new to Midi, I’m a sound engineer so not really using it to perform live but rather to control gear. I recently acquired a Yamaha O3D mixer which has full Midi control. It’s an old machine, but there is a control software for it called Visualizer o3D. I have the software on my Windows laptop, and I’ve had my first attempt at getting them to talk to each other. I nearly just got there, but there is just a single detail I can’t wrap my head around.

So the software talks to com ports (and only com ports), and there are two ways you can connect it to the mixer: straight through a serial cable but after some research, it turns out you need a special Yamaha cable (it has an 8 pin mini din at the back) which I couldn’t find, or through a Midi serial interface straight to the 5 pin Midi in and Midi out ports. Now, I’m using a newer laptop that doesn’t have com ports, so I figured a USB to Midi controller cable will to. I bought one, plugged it in, and before I knew it, realised it wasn’t being seen as a com port (which is only logical). Next, after some research, I was looking into a hardware solution but luckily someone developed a (software) com to Midi interface, so I installed it and managed to get the Midi in and out of the USB interface to talk to it. At the other end, it would send to a com port. Then I figured “if only virtual com ports were a thing” and before I knew it, I ran into yet another piece of software that does just that. So now I have the following: The control software talks to a virtual com port, the midi to com interface talks to another virtual com port, and the two are connected by the virtual com software so that the control software talks to the midi to com interface. Then the Midi to com interface talks to the physical USB to Midi interface, which then talks to the mixer through its Midi in and out ports. And it works, one way at least. Everything I do on the mixer, shows up on the software and the midi to com interface has a monitor so I can see all the messages going through. So that works, but when I do something on the control software, nothing happens on the mixer, regardless of the Midi messages actually going through to it. The software should control the mixer just like the mixer is controlling the software. The mixer is receiving them but simply not responding. The mixer also has a Midi monitor so I can see what’s coming through, and here’s the twist: I’m seeing 7 byte sysex messages coming out of the control software and going into the USB to Midi interface, but only 3 byte messages actually arriving at the mixer (more specifically the first 3 bytes of the sysex messages, which are all the same) and they’re all the same 3 bytes again and again. I figured that’s where the problem is but I don’t know for sure. Maybe I got it wrong and it’s supposed to see just 3 bytes. That’s why I’m here: what am I doing wrong? If it works one way around it surely should be working the other way around.

Cheers for your help!