Control DMX via GP

Hardware
1

I know that there have been a few DMX related threads but I thought I’d start a new one since I’m looking for advice regarding my particular case.

I’d like to use programmable light on stage with my band. I have a few of these LED panels here: Stairville LED Flood Panel 150 40° RGB – Musikhaus Thomann

My entire set is already programmed in GP. In most tracks I just use rackspaces and variations and I thought it would be easy to change the color and intensity of the lights for every time I switch to a new rackspace or variation. In some songs I have a click and sometimes a backing track running and I thought for these I could program DMX chases that will run in sync with the backing track.

However I only have very basic knowledge about DMX. I know that I need an interface, a software that sends out DMX signals using the interface and I need cables to connect the lights.

Regarding the cables: I understand that DMX cables have there own specifications but that for a low-budget use case like mine it makes sense to go with regular XLR cables, so I’ll just try these, right?

Regarding the interface: There are two types of DMX interfaces: 3-pin (XLR) and 5-pin. My LED panels have 3-pin jacks and my requirements are pretty basic in terms of what you can do with DMX; so I’ll just assume that it is sufficient to use 3-pin end-to-end, regardless of what the additional functionality of the additional two pins actually is.

This sort of cable adapters seem to be the cheapest type of USB to XLR interface: SoundSwitch Micro DMX Interface B-Stock – Musikhaus Thomann
Are they suitable for my use case or is there some relevant functionality of the bigger interfaces that the small ones lack?

Software: It seems that there is a lot of free DMX software around. In my understanding I need the software to send the DMX signals and to receive midi signals from GP in order to interface with my GP gig. Is there a particular software you would recommend?

Integration with GP: I guess that’s the tricky part, isn’t it? In my understanding I need to send one midi signal to the DMX software whenever I change the song and want to change the lighting for that new song. When I want effects to run through a song that I run a click to, is that something I would program in the DMX software and then only trigger once from GP or would I program a complete midi track and run it in GP?

2

I’ve never done anything with DMX, but I’ve looked at it in the past in the context of home automation (as opposed to stage lighting). I really only went far enough to figure out it wasn’t the right solution for what I needed.

My high level summary of what I learned is that “DMX” itself is similar in concept to “MIDI”. It’s a specification of 1) a data protocol, 2) the physical interface it is communicated over, and 3) the electrical and timing characteristics for communicating that protocol over that interface.

I believe the physical layer is RS-485, which is what I happen to use in other household applications [pool automation, HVAC automation, home security], which is why I stumbled across DMX. I think the official spec is 5 pin DIN connectors, but it’s very common on XLR connectors in practice.

A device saying it is “MIDI compatible” doesn’t necessarily tell you much about what you can do with it. Similar with DMX. e.g., you can have a MIDI keyboard that’s velocity sensitive, sends aftertouch (mono or poly), has bunches of knobs and faders, etc. Or one that just sends note on/off and nothing else. Similar for the responding device, which would generally be a light for DMX (although people use it for stuff like fireworks), or a sound generation device for MIDI.

DMX devices generally have an “in” and “out” port, as the DMX spec generally expects multiple devices to be connected in daisy chain style (that’s how RS-485 works). RS-485 itself can be bidirectional, but I believe DMX is one-direction. In other words, your DMX controller gives orders and your lights take orders but don’t have a mechanism to respond. (I could be wrong about that, I’m going from memory.)

So…

For GP to control DMX you’ll need: A) something to translate MIDI commands to DMX commands, and B) a hardware interface that will connect to your DMX cable(s).

Given the way you described your needs/goals, I suspect your simplest practical solution would be a small hardware box that converts MIDI to DMX. I have zero experience with such devices, but the first thing that shows up in my Google search was DecaBox Midi to DMX Bridge – Engineering Solutions Inc (response-box.com)

Most of what that particular box seems to do is translate Note On and CC messages to DMX messages. That’s your protocol and hardware conversion. It would be up to you to figure out what DMX messages your lights need to receive to do what you want them to do, and what MIDI messages are required to do it. Then you’d have GP produce those MIDI messages at the right times.

There are, of course, much more elaborate solutions. There are free software solutions and paid software solutions. My understanding of the more sophisticated solutions is you can program those to do things like fade lights up and down, crossfade between colors, etc. and you can trigger those “sequences” with a single MIDI event.

That’s pretty much all I know. Probably not terribly helpful, but I remember when I was first looking for DMX information it took me a little while to piece that much together so I figured it might be useful.

2 Likes
3

The official standard learns that cables with an 120 ohm impedance should be used. Normal cables are 75 ohm, but with not too many devices you can probably get away with them. The hardware connect itself is balanced, so xlr-3 cables must be fully wired (most of time they are, although not with dmx).

Dmx512-a is a somewhat different beast: xlr-5 is required (but I guess xlr-3 might be working as well).

Don’t forget to connect a terminator (120 ohm resistor) to the last device in the chain. The protocol runs at 250KHz, so without terminator the signal becomes really ruined with cables more than a few feet (learned that myself the hard way).

I only Googled this and found Wikipedia to be helpful. I’m by no means an expert on the subject.

1 Like
4

Though i can’t tell you in detail how to use Gig Performer with a DMX-Software, i would like to to recommend a free and relatively easy to use DMX-application which i used this year for the first time time to control our lighting on a small party-dancefloor (around 5x5m, several LED-fixtures):
https://www.qlcplus.org/features.php
I haven’t used it with MIDI neither, but from what i read, you should be able to call the diffrent scenes and chases, which you have to set up in the DMX software, by simply sending MIDI commands to the DMX application (quote: MIDI support of Notes, Control Change, Program Change and Beat clock).
Only thing is to have a working MIDI-connection between the applications (Gig Performer and QLC)… but there are several software solutions for this available too.

1 Like
5

We use qlc dmx midi controlled from gp every weekend and also use osc to control lighting rig with remote IPad

Checkout Edward Richards videos on YouTube - you can also contact him via email- he will help with anything Dmx related .

We use interface below- never had any problems with it- with moving head , led boards and static led pars.

Also we only use correct branded dmx cables and terminators not mike cables.

USB to DMX 512 3PIN XLR Interface Adapter Computer PC Stage Lighting Controller Dimmer USB to DMX Freestyle Software RS485 Serial Converter Cable (Length:3ft)

Midi to dmx

3 Likes
6

Thanks a lot for all the replies! I think I’ll be going with DMXControl 3 for my first steps. Any experience controlling it from GP?

7

Hello! Bringing an old thread back to life here - I’m taking my first tentative steps into controlling DMX stage lighting from GP and have been following the QLC Plus Youtube tutorials with interest.

My aim is very basic control of scenes and chases from Midi messages sent from the Streaming Audio Player in GP. Is it possible to control the QLC application directly from GP like this, or is an intermediary app such as the SFX 6.7 used in the above tutorial necessary?

8

We have used gp with qlc dmx - works well

9

Thanks for your reply. I’m having no luck getting QLC to respond to any Midi messages sent from GP. Obviously I need to fiddle around further.

10

Make sure your midi out is set to on in GP.
And you need to set up midi settings in qlc corrrectly.
This is what I was sent to help with midi control.

You can email the guy that sent me this on
Richard
ctltech2@outlook.com
Yes is more knowledgeable than me.

OK….the midi issue

A couple of things come to mind

  • Make sure your midi controller is connected and operating before you boot up the QLC+ software
  • Select the “Inputs/outputs” tab and make sure to check the “input” box for your midi controller which should appear in the list
  • You can also check the output box if you want to send midi feedback to your controller
  • Click on the “profile” tab (top right of screen) and select “none”
  • Now when you wiggle any of the sliders on your midi controller you should see a joystick icon appear in the universe area of the input/output page
  • If the joystick icon appears then we know we have midi connection

Now the file I sent you was originally set up for OSC. You may have to go through each widget (slider, button) and use “auto detect” to set up which slider/button on your midi device controls which slider/button in the virtual console. See video:

Finally, if you are using midi software to control QLC+ and you are using “loopbe” as a virtual midi cable, do not assign output to “loopbe” or it will cause midi feedback and “loopbe” will automatically mute. To fix this, uncheck the output to “loopbe” on the “input/output” tab then click on the loopbe icon (bottom roght screen taskbar) and un mute loopbe.

Another thought about the midi thing

  • Go to the input/output tab in QLC+
  • Select your midi device so it is highlighted in Blue
  • Look at the bottom right window: does it say “status:open or “status:not open”
  • Click on the wrench/screwdriver icon next to this window
  • A configure midi plugin window will open: Here you can set:
  • Midi Channel
  • Midi Mode
  • Some initialization messages some of which applies to Akai equipment

Back to the top left of the input/output window

  • Select profile tab
  • There are some akai profiles here that might help ??
  • Select one of the Akai profiles so it is highlighted in Blue
  • Click the pencil (edit) icon over on the right side of the screen
  • Input profile editor will open
  • Click on channels and assignments for each button, slider, etc, will appear
  • The channel number is just a number that QLC+ assigns for that particular controller (need not worry about that)
  • Click on column headers to sort: for example if you click on name it will sort by the names of the controllers

Hope this helps

2 Likes
11

Thank you for your help. I’ve got it responding to GP Midi notes now - just a case of exploring QLC+ further now to get it to do what I want.

1 Like