Draft:Source Four

Source Four (Source 4 or S4) is the brand name for entertainment lighting fixtures manufactured by Electronic Theatre Controls (ETC). The name originally applied to the HPL lamp and ellipsoidal reflector spotlight (ERS) first produced in 1992, but now applies to the series of related fixtures, and often (erroneously), for any type of ERS. It can be combined with interchangeable lens barrels to achieve different field angles, or other fixture bodies to become another luminaire type such as a PAR or Fresnel. It is commonly found in theaters, film/television studios, concert halls, museums, and other multipurpose spaces.

Incandescent models use 375 watt, 575 watt, and 750 watt High Performance Lamps (HPLs) manufactured by USHIO. All Source Fours are constructed from die-cast aluminum. The Source Four is named for the four-filament design in the lamp invented by David Cunningham and Greg Esakoff of Entertec. The main advantage of this specific design is its improvements to light emission and heat dissipation.

Source Four
The namesake for the series. There are also two zoom barrels that can angle 15° to 30°, and 25° to 50° respectively. It features a 25° rotating barrel and three-plane stainless-steel shutter blade assembly. It can hold A, B, and Glass size patterns and gel media holders range from 6.25" to 14" frames depending on lens barrel. Standard Source Fours use line dimming from a dimmer pack.

Source Four jr
The Source Four jr is a smaller, less expensive version of the source four fixture. It comes in four barrel angles: 26°, 36°, 50°, and a zoom lens between 25° to 50°. Unlike the standard Source Four, the Source Four jr does not have interchangable lenses. It is equipped with an M-size pattern holder and 6.25" gel media holder. This model uses HPL lamps for line dimming.

Other Models & Lines

 * The Source Four LED line uses an LED array called Selador X7 after the company it aquired in 2009.
 * Source 4WRD (a play on words of "four" and "forward") is a line of LED lamps meant to supplant conventional Source Four lamp bases, first introduced in 2016. Source 4WRD Color introduced an RGBA LED Array. It is compatible with any full-size Source Four fixture including PAR and Fresnel.
 * The Source Four Mini is the smallest fixture in the Source Four line at 9" long. It is mainly for use in museums and lecture halls
 * The Source Four PAR, introduced in 1995, is a fixture body that attaches to the Source Four Lamp base to act like a PAR64 lamp. It's main advantage over a conventional PAR is that the fixture uses the HPL lamps, rather than the large PAR64 bulbs.
 * The Source Four Fresnel
 * The Source Four Revolution is a discontinued moving head fixture. first introduced in 2004. It included a color scroller assembly, motorized zoom, pan and tilt functions and uses a QXL lamp.