Hi everyone, this is my first post on here. I have done a search and only found one other topic that asks only half of my problem that I have (but no answer was given that has helped me).
Im running a Sub 37 (firmware 1.2) with Logic X (latest update 10.3). Everything has been running fine until all of a sudden I have just started encounter problems that have been giving me a massive headache and have spent about 2 days trying to figure it out.
The Sub 37 is plugged in via USB MIDI into my imac, the audio out jack into my scarlett 18i20 soundcard into input 1. The Sub 37 shows up in Audio Midi Devices on my mac and works fine when I test the device. However here is my first problem..
As soon as I open Logic the Sub 37 flicks on the arpeggiator and starts playing randomly (every single time I open Logic no matter how many times i restart either the sub 37, logic or my mac) I have also reinstalled the firmware on the Sub 37. Now, I read somewhere about this possibly being a MIDI loop and turned off Local on the Global settings but this did nothing. Also if the sub 37 was working fine before and I didnt change anything then surely I wouldnt need to do this right? Secondly once I turn off the arpeggiator after starting Logic, I get a sustained high note that will not stop unless I play a note, but then continues once i release whatever note ive played. That is my first problem.
The second main problem involves the External Instrument in Logic. Now, I know that my mac is picking up the Sub 37 as a device but when I go to the MIDI destination drop down list in the External Instrument, which previously would have Moog Sub 37 as option, it is no longer there and its driving me insane as it used to just be there and I can no longer use the synth properly with USB MIDI until im able to select it. My other USB MIDI synths are there in that list but not the Moog! And I literally have no idea what else to do to solve this problem/s
Any help would be very much appreciated! Thanks guys
Right just a little update here. The sub 37 works fine on my macbook pro, running Logic X. No random notes on startup and the Sub 37 is recognized in Logic. So im guessing the problem lies within Logic on my imac…
Hey alexgraysonmusic, welcome to the forum!
About your first problem, I don’t use computers for music anymore but… I remember Logic can open loading the last used project, right? Maybe there is some initial MIDI message launch with that very project.
Check whether this happens when opening Logic without any project or with some of them only etc.
Hope this helps a bit, some other forumers should chime in 
Hey stiiiiiiive, thanks for the reply. Yes I have tried with different projects and also blank projects and also templates I had previously created with the Sub 37 already setup as an external instrument, and still nothing. I even saved the project template from Logic on my macbook, which the sub 37 works fine and opened it on my imac but the Sub 37 is still missing and continues to make random noises.
You may want to try with a single MIDI cable from your MIDInterface output to your Sub MIDI DIN input. Just thinking outloud, sorry 
The Sub 37 works fine using a MIDI cable, so therefore the problem must be over the USB connection. I dont mind being able to use it with the MIDI cable but I was a fan of the Sub 37 Editor which can only be used if working via USB. Are there Sub 37 drivers for USB connection? I can’t remember if there were and ive had a search but the only downloads on the website are for the firmware update and the sub 37 editor. Thanks
Also just one more update. The Sub 37 works fine over USB in Ableton on the same imac which im having these Logic issues on
I won’t be able to advise any further, mate
Anyone?..
From the description it sounds like the problem lies in what MIDI messages that particular installation of Logic sends out. I’d use a MIDI monitor to diagnose the problem. Since you’re on a Mac, MIDI Monitor should do the trick.
Thanks for the reply DrJustice, but the MIDI monitor is saying there is no additional MIDI notes coming out, which is just so weird as there is clearly something triggering the synth. The MIDI monitor works fine and shows when I play my seperate MIDI keyboard. Also when I play notes from the Sub 37 I can see the MIDI notes at the top of logic in the transport bar, so its strange the MIDI monitor is not picking these up.
I can get the sustained note off by holding down both octave buttons on the synth but then it will just start again once i hit record in logic.
I dont want to do it, but I think im just going to have to completely remove logic and do a clean install. urgh
Hi alexgraysonmusic
I’m having the same issue. It started with my Moog Sub37 on Logic Pro X then the issue affected all my outboard gear.
As soon as I press record on Logic the synth goes crazy. All the midi parameters on the synth (even the Logic channel volume control) start jumping around. It’s been impossible to use the synth with both USB or normal midi cables.
I’ve done a factory reset on my Moog but that didn’t work.
Yesterday I uninstalled then reinstalled Logic. That has seemed to work for my other outboard gear but not the Moog via USB. I will try it will normal midi tonight, hopefully that will work.
I’ve just acquired a copy of Ableton 9.1. If it works on there I think I will be to ditching Logic.
It’s all very, very annoying.
Hi foolphat, after reinstalling Logic X and updating my imac to macOS sierra, my Sub 37 now works with Logic over USB MIDI. I have no idea what caused the problems before but currently Logic version 10.3.1 with Sierra seems to be working fine