Whenever we are invited to the table on a House of Worship design, inevitably, one of the first items that comes up is a discussion on how to control the house lights. In more modern sanctuary spaces with theatrical lighting components, a common thought is “well, obviously these house lights have to be DMX controlled” and/or “I don’t want to allocate all of my lighting budget to generic house lights”; in more traditional spaces, we often hear “but I need this to dim like incandescent” or “can’t I just have a dimmer box on the wall”. As it happens, both users are asking for the same thing. They need a house light that can be controlled from the console and the wall station; they need good low range dimming performance, and they need all of this in a cost-effective solution.
While no one is arguing the merits of a DMX-based solution for those houselight applications that will truly utilize it – those that use a RGBW color changing fixture, or a space that often changes shape – the majority of houselight control strategies ultimately require a delicate balance of function, performance, and economy. Often, DMX is chosen out of habit or familiarity, rather than driven by the true functional needs of the space. Other venues elect to use 0-10v, but still need to manage low range dimming concerns and integration with control consoles. Modern versions of reliable standards are able to rebalance these priorities in order to give owners an efficient solution without requiring them to choose their best two-out-of-three.
In designs that are adamant about using a DMX-controlled house light, this preference often comes back to a hold-over assumption from the incandescent era that the only way to get the console to talk to the fixture was to use a DMX-backed dimmer so that the console could talk to the circuit. As lighting and control technologies have evolved, the pinnacle of control has long been held to be a fixture that can mimic the performance of the incandescent dimming range. In the days in between incandescent and LED house lights, fluorescent fixtures in several form factors made use of dimming drivers and these fluorescent sources fulfilled two out of the three criteria – functional simplicity, and economic viability – but when compared to traditional incandescent sources, it could not match the dimming performance, so for many venues, 1% and 10% dimming was as good as they could get. For other venues that could not sacrifice dimming performance, hybrid solutions between HID sources and incandescent sources lessened the impact of high-density racks. With the advent of specification-grade LED fixtures into the marketplace, alongside digital DMX drivers for the architectural lighting market, suddenly this goal became much more universally achievable.
Undoubtedly, in the shift from incandescent to LED sources, there is reduced cost in terms of power infrastructure. But embedding DMX into a houselight – and in this case, we are looking at strictly white light, hardwired applications – is more complicated than it looks and implementing this successfully adds its own set of costs to the project. For example, depending on the size of the sanctuary, you will have device limitations, normal vs. emergency power control considerations for which there a separate set of equipment is required, added fixture addressing and wiring complexity, low voltage conduit spacing rules for separating high and low voltage wiring, end of line terminations, and more. The question that must be asked and answered is “does all this added equipment and complexity really serve the needs of the space?” Designers must have a mind to consider that most of the users of the lighting system in a house of worship are non-technical volunteers and balance the complexity of controlling all these loads so that the non-technical volunteer is not overwhelmed with the user interface, while still providing a featureset rich enough for the technical user to interact with the space in an efficient and meaningful way.
In its former life, 0-10v was a commercial performance standard whose limitations were accepted as fact. It provided a space for advancement in fixture output performance but could not quite get to the low-level dimming output of incandescent sources. Where fluorescent driver dimming thresholds were limited because of the minimum amount of current required to maintain the gas excitation, LEDs do not produce light this way and thus, are not limited by the current minimums of fluorescent fixtures. Modern 0-10v dimming solutions allow designers to meet all three criteria of functionality, performance, economy with to the advent of programmable drivers and deep dimming solutions. The old analog standard of 0-10v is now reborn with a programmable interface, allowing manufacturers to set the dimming threshold down as low as 0.1%, and applications in which we previously defaulted to DMX to achieve the low-end incandescent-like dimming can now achieve the same level of performance over more familiar four-wire dimming. Where much of a project’s cost impacts used to be tied up in high-density dimming, the evolution of LED performance has reduced the power infrastructure needs to the point where an 8-relay panel can replace a 24-circuit dimming rack. More recently, many manufactures have begun to offer their relay panels with both a DMX control bus, and 0-10v dimming outputs – solving the problem of getting the console to talk to house lights without going through a series of external interface boxes to do so. In simple houselight applications, auditorium houselight control needs the ability to dim in rows or groups from front of house to back of house. Depending on the size of the space, you may have aisles, balconies, under-balconies, or other specialty zones, but rarely do any of these require individual control of each fixture in order to accomplish this goal. DMX-controlled relay panels with 0-10v outputs will accept houselight control from the console, consolidate the power infrastructure, and allow for a reasonable amount of control granularity – a zone- or circuit-based allocation – instead of a fixture-based DMX solution.
So how do we answer these questions? Can we control it? Is DMX control worth all the added infrastructure? How do we determine which control solution is best? For some – that answer is undoubtedly a DMX solution – it is a multi-use space, or there is a large amount of technical integration with stage lighting or AV systems, or the client wants to use a color-changing house light – for these applications, DMX control at the fixture level certainly makes sense. But for other sites, where the targets are a highly efficient houselight fixture with good low range dimming performance, control from multiple locations and no need for the added features of a DMX houselight – these applications can get the best of all worlds through a deep-dimming driver, coupled with a DMX controlled, 0-10v relay panel. Streamlining old standards to their most efficient forms allows owners to quickly achieve the best function and performance for their budget. Widespread availability of deep-dimming drivers means that aesthetic is not tied to dimming performance, so no matter the fixture shape, the low-end dimming performance is consistent across all form factors. LED efficiencies enable good uniformity while minimizing power density and controlling these fixtures from a console no longer requires multiple interfaces to get from houselight to console to wall switch. These adaptations are concise and scalable for any size application and are a reliable solution for any designer’s tool kit.
This article was originally featured in the August issue of designing lighting (dl)