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Asked: 2026-05-25T01:13:20+00:00

2 questions 1: Q light software… I have a Showtec Showmaster 24 which is

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2 questions

1: Q light software…

I have a Showtec Showmaster 24 which is a DMX controller with 24 channels. I have plugged it’s MIDI input into my PC using a USB/MIDI cable. QLC picks up the MIDI connection and I have assigned the MIDI channel as 2. The light desk tells me how to set up the MIDI input channel which is done, it tells me how to set it to wait for download dumps from the PC.

When it is waiting, it expects a single byte value of 85 as the beginning of the data block followed by the filename DC1224.BIN followed by a space. Then a file dump follows.

Bytes 22 to 69, notes that switch on/off the 48 chasers. The velocity is the program master.

Bytes 70 to 93, notes activate channels 1 to 24. Velocity controls the intensity.

Anyway to finish off the scenario I also have 4 LED cans which match perfectly to the StarVille LED PAR 56 built in fixture in QLC.

Anyway, when I set the lighting desk to listen to MIDI channel 2, route the QLC output to MIDI 2 using note velocity mode, setup a set of sliders that are mapped to one of the cans DMX address nothing seems to change when I raise or lower the slider for any colour.

Is there a plugin for this desk or is there a way to make it work?

Question 2:

Following on from QLC I am writing my own software with source for MIDI in/out control. So assuming that I can output to the lighting desk, send the same sequence – byte 85, the filename and space, what follows?

I have the standard MIDI API for lighting which I have browsed does every command sent to the desk follow the same header?

TIA

Andrew Sprott

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1 Answer

  1. Editorial Team

    OK, solved the problem, the solution is to use the following sequence of bytes as a header for each packet sent to the desk :

    $55+’DC1224.BIN ‘

    The filename is used by the desk for communicating with other desks when synchronising.

    What follows is a MIDI show control message with note on, pitch and velocity parameters. The device id is whatever the connection is to the lighting desk, a usb/midi cable for example.

    The note on instruction uses the midi channel as it’s lower 4 bits. The pitch is the colour channel in the DMX universe added to the base 70 – 24 channels 70 to 93 – and the velocity is the intensity, but remember you need to scale it from 8 bits to 7, in other words, new_colour=old_colour/255*127.

    But anyway, It works.

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