Let’s explore some answers.
DMX Merging, Defined
First of all, DMX merging is when two or more sources of DMX are combined into one control stream in order to control a single set of lighting fixtures. Typically, either the intensity and/or color mixing channels of those fixtures are controlled, and the two or more sources will have to battle it out for the control. In a system using DMX merging, the winner of that battle is usually always the highest value present (HTP) as opposed to the latest value (LTP). In other words, if two or more sources are sending a signal to the exact same unit, the signal with the higher value takes precedence, and the lower value will be disregarded.
In the system I designed, I wanted to use DMX merging to send basic CMY values along with pixel-mapped video to a grid of GLP Impressions. There are many DMX merging boxes available, but because I had chosen to use the PRG Series 400 power and data distribution system on this show, I opted to use its built-in DMX Merging capability; no additional equipment was necessary. This feature is sometimes overlooked, but it is just sitting there waiting to be utilized, so I took on the challenge.
First, I had to map out the signal flow from the two sources of DMX that I would be using. On this project, I had a lighting console (the Full Boar from High End Systems) and a media server (the Mbox EXtreme v3.5 from PRG). I would be configuring both of these devices to send out CMY values for the same set of GLP Impressions, so I ran both of these devices directly into the Series 400, created a pixel map on the Mbox, and then, after making some adjustments to network IP addresses on both the Full Boar and the Pixel Mapping output on the MBox, I was in business.
As I played a video clip on the MBox, I was delighted to see the CMY values flickering on the face of the Impressions. Of course, since the Impression only allows all of the LEDs on the face of the unit to be controlled as a single pixel, I had to settle for a very low resolution representation of the video clip, but the overall desired result of movement and energy was achieved.
Why Do It?
Now to the question of why. Why did I want to use this feature in the show? Well, the answer was simply because of the placement of the Impressions. On this show, I had designated six vertical trusses interspersed between five 6-foot-wide panels of LED video. I wanted to have the capability of showing a video clip that was playing on the LED video wall and displaying it across the Impressions also while they ballyhooed and strobed during the show. And I found the PRG Series 400’s DMX Merge feature was just one of many solutions
DMX merging can transform an otherwise typical lighting design into something much more dynamic. Many recent music awards and reality singing shows utilize pixel mapping, media servers and merging with both LED lighting fixtures as well as conventional lighting fixtures like the Jarag line from Chromlech. So the next time your lighting design calls for something a bit more visual than just color or intensity chases, try using DMX Merge and pixel mapping a video to that grid of conventionals or LED fixtures…it will be well worth the effort!
DMX Merging Solutions
After taking on the challenge of merging DMX control for a recent show using the built-in DMX merging capabilities of PRG’s Series 400 power and data distribution system, I started researching additional gear that can provide a DMX merging solution, and was surprised to find quite a few options. Here is a short list to get you started in case you are interested in merging DMX:
Artistic License Protocol-Converter; artisticlicence.com
Baxter Controls Pocket Console DMX NETport; dmx2go.com
Doug Fleenor Design DMX512 Combine Unit; dfd.com
ELC Lighting DT221 mkII DMX merger; elclighting.com
ELM Video Technology DMG DMX 512 Merger/Combiner; elmvideotechnology.com
Enttec Datagate; enttec.com
grandMA NSP (2 of the 4 DMX connectors can be configured as inputs for merging); malighting.com
Leviton DMX Signal Management & Input Merger; leviton.com
LSC Lighting Systems DMX512 Merge DMiX; lsclighting.com
Luminex (makes a variety of Ethernet-DMX network nodes that can be configured for merging; also makes a multiple port configurable DMX512 hub); luminex.be
Martin Professional Ether2DMX8;
martin.com
Pathway Connectivity (makes a variety of devices that will merge DMX from multiple sources); pathwayconnect.com
PRG Series 400; prg.com
Showtec DMX Merge; showtec.co.uk
Swisson XMG-51 DMX 5 to 1 merger; swisson.com
