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When selecting equipment for an auditorium’s technical systems, it’s important to consider how your selections may affect your clients in the future. In the world of theatrical lighting, one of the important infrastructure decisions is how to send lighting data to dimmer racks and fixtures.
A couple decades ago, the selection was pretty simple: DMX was the way to go. This industry-standard method of transferring lighting control over two-pair shielded cable was supported by virtually all manufacturers, and its support of daisy-chaining the control cabling from one fixture to another made installation simpler. One DMX cable would support one universe of DMX, which is 512 channels of data. A single dimmer would use one of these channels for control; a moving light may use many channels for each fixture. If you need multiple universes of DMX, you need to have a separate cable run for each universe.
A couple decades ago, the selection was pretty simple: DMX was the way to go....
An add-on to DMX, Remote Device Management (RDM) allows a lighting controller to ask a “who’s out there?” question and lets RDM-enabled equipment respond. The controller can then set configuration information, reducing or eliminating the need to break out a lift to change a device's configuration.
Some manufacturers also created proprietary protocols that work over Ethernet. Electronic Theatre Controls (ETC) created ETCNet, primarily supported only by ETC. MA Lighting developed MA-Net, again supported by MA Lighting’s control systems. These Ethernet protocols allowed for more sophisticated communications between the lighting console and other equipment, supported multiple universes of DMX through one inexpensive Ethernet cable, and allowed status and other information to be transferred back to the console.
The problem with these, however, is that if you installed the original ETCNet or MA-Net systems as your infrastructure, you were pretty much locked into ETC or MA Lighting as your equipment supplier. Awesome for the manufacturers, but not so great for the end user. This is typical of new technologies across most fields, though, and as time goes on and technologies mature, new infrastructure types tend to become standardized and supported by more, if not most, manufacturers.
New alternatives
Since that time, new protocols that use standard Ethernet wiring have come into existence. Ethernet cable is less expensive and easier to run than DMX cable, and can support numerous universes of DMX channels. Some protocols are more prevalent than others.
Art-Net, created by Artistic License, was one of the first open protocols and is widely supported. Most consoles that support sending control data over Ethernet will support Art-Net. Art-Net primarily re-packages DMX universes into its own communication protocol and can transfer numerous universes of DMX over one low-cost Ethernet cable, reducing the cost and effort of wiring the system. Art-Net also provides the ability for RDM message to be transferred through its protocol.
As lighting systems started controlling far more than basic lighting fixtures, it because apparent that a system that would better support a wider variety of devices could be useful.
As lighting systems started controlling far more than basic lighting fixtures, it because apparent that a system that would better support a wider variety of devices could be useful. In the early 2000s, a group of representatives from numerous companies and organizations came together and developed the ACN (Architecture for Control Networks) suite of protocols. ACN is thorough and modular, but its adoption has been slow, probably due to its complexity.
In the interim, a subset of ACN was developed called sACN, or Streaming ACN. This is a lightweight version of ACN that is primarily focused on transferring DMX information over Ethernet, much like Art-Net. sACN has been widely adopted, and most manufacturers that support Ethernet methods of transferring control information support sACN now.
Other more proprietary protocols also sprung up, including Pathport by Pathway Connectivity; Shownet by Strand; KiNET by Color Kinetics, and eDMX. These do not have widespread adoption and are falling by the wayside in favor of Art-Net and sACN. Most manufacturers who developed their own Ethernet-based protocols are now also including at least sACN support in their new products.
While Ethernet transfer of lighting control data has become widespread, individual lighting fixtures still typically expect the old-fashioned DMX connection. To support these fixtures, you would install an sACN or Art-Net to DMX converter, or “Node,” near where your fixtures or dimmers are located to connect your devices into the network. More expensive fixtures and dimmer racks may support sACN, ACN or Art-Net directly and have Ethernet-In and Ethernet-Through to support direct wiring into your Ethernet control network.
Implications for church projects
So, how does all this effect your church clients? The installer needs to understand what equipment their client already owns that they will want to connect into their lighting system, as well as what they might want to rent or borrow for special events. While you might be able to install a new lighting system as Ethernet only, will that prevent them from renting lower-end moving lights that require DMX cabling? Or do all the pieces of equipment you are considering “speak” a common protocol like sACN?
... if you install DMX cabling only, will that limit them going forward? It certainly seems that Ethernet is the future of lighting control distribution.
Likewise, if you install DMX cabling only, will that limit them going forward? It certainly seems that Ethernet is the future of lighting control distribution.
Therefore, it’s important to understand the full range of options that your church client may need, and ask probing questions to make sure they understand the ramifications of their answers. Often church staff are not that familiar with the technical details, and their answers may change if you ask more directed questions like, “Are there other fixtures in your facility that you might want to bring over for special events?” If so, equipping them with some Art-Net or sACN to DMX nodes might be wise.
Making sure that all the equipment chosen can work on the same control protocol, and ensuring that legacy equipment can be supported at key locations in the auditorium, are important things to add to your checklist when building or renovating your client’s facility.
