App Note:
DMX Machine or LightCue?
How to Choose.
Alcorn McBride makes two completely different products for lighting control: The DMX Machine and The LightCue. Both products have characteristics that make them more practical than conventional lighting boards in permanent installations. The different feature sets of the two are aimed at very divergent applications, however. This application note compares the two products, and describes typical applications for each.
Director of Engineering
Lighting DMX Machine


The LightCue's primary function is as a lighting board replacement in automated applications. Rather than leave an expensive lighting board in a fixed installation the LightCue can - independent of manufacturer - record the DMX-512 output of any light board and then replay it, locked to timecode. Since it occupies only one unit of rack space and costs far less than a lighting board, the advantages are obvious.


But the LightCue can also do some tricks that many lighting boards can't. For example, it can independently handle six such recordings simultaneously - and asynchronously. In other words, you can have certain channels dedicated to the main theater, others to the pre show, more in the post show, plus additional static or triggered looks elsewhere around the facility - in shops, restaurants, etc. The LightCue can play these recordings independently and simultaneously. It "piles on" the DMX channels from each area, combining them into a single DMX512 feed to your dimmers. That means that you can change the restaurant lighting while the main show is running, without either area affecting the other.


A completely different LightCue application is in a facility such as an entertainment center, where six smaller - possibly even identical - shows could all be run from a single LightCue. The recording can be triggered by timecode, contact closures, serial messages or front panel pushbuttons, providing plenty of versatility.

The LightCue can actually store up to 255 different shows, all on its removable media. Often these recordings include blackouts, work light settings and bulb test routines. And depending upon media size, the recordings can be hours - or even days - long. Because the media is removable, changing shows seasonally is as simple as popping out one Compact Flash card and inserting another.

DMX Machine

The DMX Machine is more than a lighting controller; it's really a complete show controller, incorporating logical, math and timing capabilities in a single, inexpensive box. It is programmed using a Windows-based scripting language. Once downloaded, the script resides in the unit, forming a complete lighting controller for one or more shows, exhibits or spaces.

The DMX Machine functions differently than a lighting board, because each script can contain up to 256 "sequences". A sequence can be thought of as similar to a lighting board cue, but it's actually far more powerful. That's because each sequence not only has control over up to 512 channels of DMX, but it can also perform a nearly unlimited number of sequenced "events". That means that when a sequence first starts it can set some lighting levels, then set others a few seconds or minutes later, and go on making changes for over a half hour. It can even loop back on itself to created chases or other repeating patterns. And that's just a single sequence; there are 256 of them!



Typically a given sequence is used with a subset of DMX channels to accomplish a particular task, for example:

  • Cycle a theatrical show
  • Light different exhibits sequentially after a pushbutton is pressed
  • Create a slow sunrise to sunset fade in a restaurant or mall
  • Flicker candle flames pseudo-randomly

A single DMX Machine can - and often does - perform all of these operations simultaneously. It could be generating chase sequences and flicker flames in rooms all over your facility, and still easily handle many exhibit or show sequences started by contact closures, front panel push buttons, or serial messages. But remember: you have to write the script for your DMX machine, it doesn’t record DMX. DMX Wizard, a Windows-based tool that comes with the DMX Machine can help you set your levels, by providing a screen full of virtual sliders that control the DMX Machine’s output.


The LightCue and DMX Machine are powerful, economical products that replace or even surpass lighting boards in many applications. In short:

  • Use the LightCue when the lighting designer is done programming a complex, automated show, and you want to eliminate the lighting board.
  • Use the DMX Machine to script up to 256 smaller shows, exhibits or effects.



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