New Piston Rail creating 'Midi Feedback' Error

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damuehlbauer
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New Piston Rail creating 'Midi Feedback' Error

Post by damuehlbauer »

As a part of my project to build a new three-manual keystack, I am building new Piston Rails. I have one partially completed and it appears to be working correctly with Midi-Ox, but when I connect it to Hauptwerk I encounter a problem.

The problem occurs on the General Settings, Midi Ports screen. I built another piston rail several years ago using similar components from the same supplier, Midi-Hardware (in Poland). That rail works perfectly with both Midi-out and Midi-in on the same channel on my Midi128 Express. When I connect the new rail to the same Midi-in and Midi-out channel I get the 'Midi Feedback' error, which is a very threatening warning. But without the Midi-Out enabled, the lights on the pistons won't work. The pistons can be detected and they work as expected.

I will also reach out to the vendor, but I don't think the problem lies there. And everything appears to be wired correctly.
David Muehlbauer
Mesa, Arizona USA
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mdyde
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Re: New Piston Rail creating 'Midi Feedback' Error

Post by mdyde »

Hello David,

If you get a MIDI feedback warning then it means that some part of your MIDI console hardware is passing at least some MIDI messages that it receives from Hauptwerk (via one or more of the console's MIDI IN ports) back to Hauptwerk (via one or more of the console's MIDI OUT ports), thus creating a MIDI feedback loop.

In general, you would want to stop it doing that, since in general MIDI feedback can create stability problems and/or unpredictable behaviour. Perhaps there is a setting within its firmware for whether MIDI it receives should be echoed-back/passed-on via to its MIDI OUT port -- if so disable that firmware setting. The naming of the setting might also be relate to using its MIDI OUT port for MIDI THRU (which isn't part of the MIDI standard, but some devices which don't themselves have MIDI THRU ports have an option for it).

Check in its documentation, or with its maker if in doubt.

Provided that the hardware is *only* echoing-back/passing-on MIDI messages that it doesn't consume itself (as a type of 'soft MIDI THRU') and if there is no way within its firmware to disable that behaviour, then it might possibly not end up being a problem, but it's still safer to avoid it (by disabling it in its firmware) if at all possible.
Best regards, Martin.
Hauptwerk software designer/developer, Milan Digital Audio.
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pwhodges
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Re: New Piston Rail creating 'Midi Feedback' Error

Post by pwhodges »

Is MIDI-Merge disabled in your master controller (it should be)?

Are you using LITSW or LTSC for the piston rail?

Paul
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damuehlbauer
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Re: New Piston Rail creating 'Midi Feedback' Error

Post by damuehlbauer »

Yes, the problem was the LTSC (successor to the LITSW) defaults to Midi Merge 'ON'. Once I turned that off (#972) it works perfectly.

Thanks!
David Muehlbauer
Mesa, Arizona USA
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mdyde
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Re: New Piston Rail creating 'Midi Feedback' Error

Post by mdyde »

Excellent -- glad to hear it's resolved now.
Best regards, Martin.
Hauptwerk software designer/developer, Milan Digital Audio.
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