JOHANNUS console "swallows" MIDI messages?

Hi everyone,

I have a 4-manual Johannus Rembrandt 4090 from 2003, which I have been using exclusively as a "Hauptwerk" console for four years. In order to be able to use the thumb and foot pistons for "Hauptwerk" as well, without at the same time addressing the organ's internal combination system, I had separated all the pistons from the internal system, re-midified them and then assigned them to the "Hauptwerk" combination system.

The MIDI-Out of my MOTU UltraLite-mk4 is connected to a set of five 2x16 character displays from MIDI-Boutique, which I built into the console. From the last of the five displays there is a connection to the MIDI-In of the organ to display the virtual stop status of "Hauptwerk" via the illuminated stop pulls of the console. So I can use the complete console with all the controls almost entirely "headless" for "Hauptwerk", and it all works quite well, except for one small problem:

When changing registrations via the combination system or when cancelling all activated virtual stops via the cancel piston, it occasionally happens that individual stop pulls remain illuminated (or not illuminated), although the associated virtual stop has been correctly switched off (or switched on). This happens especially (but not only) in cases where very many stops are involved at the same time. As a result the “optical” state of the console no longer matches the state of the virtual organ. It seems that the internal MIDI electronics of the Johannus occasionally overlooks or “swallows” single or multiple MIDI commands to extinguish the drawstop illumination. If this is the reason, then I wonder if it is possible to somehow slightly slow down the sending of MIDI commands to the console in order to make sure that the console does not "swallow" anything. Another possibility might be to speed up the response of the console, but I have no idea how to do that.

The MIDI buffer size in “General Preferences” is set to “huge” (4096 kB), but as I understand, this buffer is only responsible for the “other direction” anyway and therefore cannot be part of the solution.

All in all, this is not a big problem, since the switching on and off of stops of the virtual organ via the console works absolutely flawlessly, only the feedback of the respective new stop state to the console is occasionally not complete.

I would be very happy if anyone knows a (simple?) solution for this (… if there is one at all …)

Thanks,
Peter

[mdyde]

Hello Peter,

My suggestions would be:

- Try using a good-quality (well-buffered) separate physical computer MIDI OUT port for the stops, rather than chaining them via the MIDI LCD units. E.g. you could use something like a MOTU Microlite. It may be that the MIDI buffers in the MIDI LCD panel units are overflowing, and chaining MIDI devices is slow (especially when lots of messages are being sent).

- In Hauptwerk, check that "General settings | General preferences | Advanced: Limit MIDI OUT port send rate to MIDI 1.0 baud" is ticked.

Thank you, Martin, for your quick response and your suggestions. I will try this and give feedback if it works ...

Best regards
Peter

[mdyde]

Thanks, Peter. You're very welcome.

P.S. If you don't currently have an additional MIDI OUT port available, just as a test you could try simply disconnecting the LCD panels temporarily (so that the existing MIDI OUT port is going straight to the Johannus, which will ignore the LCD messages). If that allows the stops to work reliably then you would know that the problem was with sending the stop data via the LCD panel units.

Hello Martin,

that's a good and actually obvious idea, I will test that first, before I buy an additional device.

Peter