Odd MIDI problem

[KyleAnderson]

One of my venues is having a strange problem, and I hope the folks here have some insight.

Near the stage there is a musician area, and our peformer has an old Kurzweil keyboard being used as a MIDI controller for a MacMini using Mainstage. The controller goes through a Scarlett interface plugged into the computer's USB.

Above the stage, and operated from an in wall switch in the control booth, is an electric projection screen. Sometimes operating the screen generates MIDI noise, which you can see an example of pasted below. The Note On and Off commanads on Channel 1 are the Kurz. The System Resets, as well as the occasional message on Channel 16, seem to be a result of the screen operating. Sometimes there is no result from this "noise." Sometimes it creates all kind of havoc for the musician that effects the show.

The noise seems to be more likely to happen when the motor stops or switches direction, though it can happen while running over the duration of its descent or ascent.

The power for the screen is run in the wall. The MIDI cables are nowhere near the screen or its power run. The Scarlett, Mac, and Kurz are plugged in on the same circuit, and it is not, to the best of our knowledge, the same as the screen. When running the gear to a different circuit known to be different the problem persists.

Any thoughts on how one goes about diagnosing a problem like this?


Example MIDI messages generated:


19:59:51.063 Scarlett 18i8 USB Channel 1 Note Off: A‚ôØ5 76

19:59:54.430 Scarlett 18i8 USB Channel 1 Note On: C‚ôØ3 104

19:59:54.463 Scarlett 18i8 USB Channel 1 Note Off: C‚ôØ3 61

19:59:54.631 Scarlett 18i8 USB Channel 1 Note On: C‚ôØ3 92

19:59:54.698 Scarlett 18i8 USB Channel 1 Note Off: C‚ôØ3 35

19:59:54.897 Scarlett 18i8 USB Channel 1 Note On: C2 117

19:59:59.263 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.264 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.264 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.297 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.298 Scarlett 18i8 USB - System Realtime: Stop -

19:59:59.330 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.331 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.331 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.331 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.331 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.332 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.363 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.364 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.397 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.398 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.398 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.398 Scarlett 18i8 USB Channel 16 Channel Pressure 127

19:59:59.398 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.430 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.431 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.464 Scarlett 18i8 USB - System Realtime: Reset -

19:59:59.497 Scarlett 18i8 USB - System Realtime: Reset -

 

[FMEng]

MIDI is an un-balanced interface, which makes it vulnerable to ground loops. Are the midi devices separate by some distance? Are they plugged into different wall outlets on the same circuit, or all together in one plug strip?

 

[KyleAnderson]

devices are right next to each other, and I'd hazard a guess the MIDI cable between the Kurz and Scarlett are 5 or 10 feet. USB to computer.

The computer, interface, and keyboard are not all plugged into the same power strips. I am uncertain whether they are on the same outlet/circuit. there are several there and I can't take a look at the runs at the moment.

Would you suggest that they are put all onto the same strip, or separated?

 

[themuzicman]

If the issue is indeed that motor, it'd be affecting something in that Keyboard or the interface for it to send MIDI messages that actually make sense to a receiving device. I don't think the cable is the problem here. At that, I think it's probably the Keyboard because of the System Realtime Reset messages - if your keyboard has any sort of auto-player functionality it would make sense that it has the ability to get and send Realtime messages.

You have one super easy option and one meh option that I know will make your life marginally easier if you can't figure out the noise problem.

1. Go out and get an iConnectivity mio2 - when I do large shows now, I lean so hard on iConnectivity MIDI Interfaces, they are super intuitive to use and program. It has integrated MIDI Mapping and filtering built in. You can pop the software open and literally tell the port "Only listen to Note On/Off commands on MIDI Input 1 only on MIDI Channel 1 and ONLY Output those values to Output 1". It can get a whole lot more complex than that, but this is the scenario you'd want it for.

Tangent: The price on the iConnectivity stuff is a steal if anyone here does massive show control and has been using dozens of MIDI Solutions boxes for years. About the only MS box I use now is a Programmable Input Selector because the iConnectivity stuff won't auto switch my QLab MIDI for me. I put QLab Main and Backup on the 2x USB Host ports of the iConnectivity, pop them out 2 outputs and into the PIP which attaches into the GPO on the console, or if it's MainStage the player gets a footswitch.

2. MIDI Solutions makes some killer boxes. They aren't as easy to program as the iConnectivity stuff, but you'd be looking at the Event Processor. The unfortunate side of the Event Processor is that you can't tell it to go "ONLY allow Note On/Off", you'd have to filter for the things actively making noise - so essentially all Note On data on Channel 16 (and possibly Note Off if the Kurzweil sends true Note Off) and either all Timing Clock Data or All MIDI Events (not sure what the Realtime falls under in Event Processor, I see Start and Stop in the programming software but not Reset, but the manual states Reset is a thing it can do).

 

[FMEng]

devices are right next to each other, and I'd hazard a guess the MIDI cable between the Kurz and Scarlett are 5 or 10 feet. USB to computer.

The computer, interface, and keyboard are not all plugged into the same power strips. I am uncertain whether they are on the same outlet/circuit. there are several there and I can't take a look at the runs at the moment.

Would you suggest that they are put all onto the same strip, or separated?

Putting them all on the same plug strip would all but eliminate a ground loop as a possible cause of the issue.

 

[KyleAnderson]

Thank you, both. I'll see what I can do with this. I appreciate the help!