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Logic 8 Control Surface Midi Input Issue

Discussion in 'Logic 8' started by paulnajar, Apr 7, 2009.

  1. paulnajar

    paulnajar Senior member

    For several years I've struggled with a random intermittent bug. It happens every month or two.

    The issue is that for no obvious reason midi input from the control surface into logic stops working. You can see the midi activity light on my Midi interface showing that the CS is still sending midi data but Logic will not see the messages. If you use the qwerty keyboard the CS receives feedback messages so Logic's CS midi sending is still working. Also, standard midi messages from my control keyboard are seen properly by Logic so it's only the CS midi input layer that has the issue.

    I use a Mackie Control setup which includes a MCU + XT + C4 but this issue seems to only happen with the MCU. It's been running on a PPC Dual 2.0 G5 using LC Xmu to split the MCU between Logic and RME TotalMix for monitor functions. Midi interface is Unitor 8 MK2.

    I had wondered if LC Xmu had something to do with it but something happened today that ruled it and any other hardware out.

    I had the MCU attached through an Emagic MT4 midi interface to my MacBook Pro and came across the exact same issue. So, different computer (Intel not PPC) different Midi interface and no LC Xmu running.

    As it only happens occasionally it's not really the biggest issue but it sure would be nice if anyone had any helpful thoughts on this.

    Kind regards
  3. Peter Ostry

    Peter Ostry Administrator Staff Member

    I know the issues you describe very well and I think the problem is on a lower level, drivers or CoreMidi. About every two weeks I have suddenly no MIDI at all. Not in Logic, not in Kontakt standalone, nor in MidiMonitor. Internal MIDI is unreliable then, MIDI from the outside vanishes somewhere. Sometimes it helps to "Reset MIDI drivers" in Logic, seldom closing and re-opening the applications brings MIDI back, a restart of the machine helps always. Logout/login would be enough, but in such cases I prefer to reboot the whole Mac.
  4. Eli

    Eli Senior member

    I occasionally have similar issues and I find that opening the Audio/Midi setup utility and using the "rescan midi" function usually jolts things back to life.
  5. johnpitcairn

    johnpitcairn Member

    Another possibility is to find the MIDIServer process in Activity Monitor and kill it. It should restart automatically.

    This sort of thing may be caused by a flaky USB MIDI driver. It need not even be one that has the hardware currently attached. Clean out those old drivers.

    Low USB bus power can also cause trouble - if you have lots of USB stuff attached, bus-powered USB MIDI devices may be intermittently failing and causing CoreMIDI freakouts.
    1 person likes this.
  6. Eli

    Eli Senior member

    This actually makes a lot of sense. I have noticed that I am most likely to have trouble with losing midi connections after I use my laser printer. I have it plugged into a UPS power supply and it trips it on every time I engage the print process. It must spike momentarily when being activated. So this little spike of USB activity running through my little hub undoubtedly jolts the other devices connected to it in a way they don't like!
  7. paulnajar

    paulnajar Senior member

    Thanks for the thoughts John. I don't think it's USB power since when it just happened on a different computer all that was drawing USB power was the MT4.

    Unless I'm missing something it all points to Logic's handling of the control surface midi IO because at the same time the bug happens normal midi IO is functioning perfectly.

    Before the fault appeared on a different computer there were 2 other possibilities - the Unitor and LC Xmu but since neither of these were being used they get ruled out. And since normal midi IO is still functioning doesn't this then allow for only one other place it can be happening?
  8. paulnajar

    paulnajar Senior member

    Thanks for the thoughts everyone. It seems I'm not alone with odd midi related issues.

    It could just be my ageing brain but I recall a time in OS9 using a serial port Unitor 8 when ALL midi communication was perfect. Really perfect. I NEVER had an issue. Since OSX and midi over USB there's been constant issues.
  9. Eli

    Eli Senior member

    Hey Paul - it's not your aging brain. If it is, we're sharing the same hallucinations :D
    1 person likes this.
  10. Peter Ostry

    Peter Ostry Administrator Staff Member

    Mhm, John's explanation says it all. We did not have so many USB devices in OS9 days. I think I have about 10 USB plugs at the moment. I consider my MIDI as reliable for what I'm doing but yes, failures increased over time. Fortunately the computers don't crash so often now. There is no free lunch ;)
  11. garethJones

    garethJones Member

    Paul - faulty MCU?


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