LED stage lighting

A front view of a Stagebar LED striplight

LED stage lighting instruments are stage lighting instruments that use light-emitting diodes (LEDs) as a light source. LED instruments are an alternative to traditional stage lighting instruments which use halogen lamp or high-intensity discharge lamps. Like other LED instruments, they have high light output with lower power consumption.

Types

LED stage lights come in three main types. PAR cans, striplights^[1] and 'moving head' types. In LED PAR cans, a round printed circuit board with LEDs mounted on is used in place of a PAR lamp. Moving head types can either be a bank of LEDs mounted on a yoke or more conventional moving head lights with the bulb replaced with an LED bank.

In actual fact, there is no such thing as an LED PAR can - it is a misnomer possibly attributed to Chinese manufacturers. As there is no Parabolic Aluminised Reflector in an LED 'PAR', they would be more accurately referred to as to as 'LED flood lights'.

Many LED fixtures are now made that through the use of a small number of high-output diodes now allow the beam to be focused to a "hard edge", allowing full use of gobo/beam effects.

LED lighting instruments used on Radiohead's 2008 tour

Uses

LED instruments can and have been used to replace any conventional lighting fixture, and some shows, such as Radiohead's 2008 tour, have used only LED lighting instruments.^[2] However, most shows use LEDs only for lighting cycloramas, or as top, side or back light. They can also be used as 'audience blinders' (lights pointed directly at the audience from a low angle).

Advantages

The 2008 Concordia College Christmas Concert used LED instruments to light the murals.

LED instruments can contain a number of different coloured LEDs, often red, green and blue, and different light output colours can be achieved by adjusting the intensity of each LED color group. LED instruments should have a long service life relative to other options, without the expense of colour gel or replacement lamps.

LED instruments are increasingly used for live music events, most notably festivals where they are more visible than conventional lighting under daylight. LED instruments were prominently used for the Live Earth festival as they are regarded as more environmentally friendly as fixture for fixture they use far less power than other lighting.

Another advantage of LED instruments is that they can be controlled directly using DMX and do not require additional dimmers; the intensity of the LEDs being adjusted by circuitry on board the fixture. Because of their low power consumption several units can be daisy chained to one power supply.^[3]

Due to low heat output, LED instruments can be used in areas where the high amount of heat conventional stage fixtures put off would not be ideal. For this reason, LED instruments are used to light ice sculptures, especially when lighting the sculptures from within.^[4]

Disadvantages

A comparison of two American DJ 64 LED Pro fixtures vs a single PAR-54 GE 300 watt medium flood incandescent.

LED instruments cannot be used to create a hard edged beam, which is needed for gobos and other effects which require the use of an ellipsoidal reflector spotlight,^[3] though LED fixtures are now made that through the use of a small number of high-output diodes now allow the beam to be focused to a "hard edge", allowing full use of gobo/beam effects. Because color mixing is done using three or more colors of LEDs, mixed colors will have multiple edges to shadows where different colors are showing; however, Elation Professional has introduced instruments that group three LEDs behind a single lens to make the multiple shadow lines less noticeable.^[5] Because of the multiple light sources in the fixture, most shadows are a soft edge as well.

As of 2008, the output intensity of LED lighting is still unable to match the luminous power of traditional incandescent lamps. A 300 watt medium-spot GE PAR-54 easily outshines a PAR-64 RGB LED Pro fixture from American DJ, which is one of the brightest LED fixtures available in 2008. The LED output spectrum is additionally very cold (blue) compared to the warm (yellow/red) of the incandescent.

Several times as many LED fixtures may be needed to match the brightness of a traditional fixture of similar size. But LED fixtures also currently cost several times more than a traditional incandescent fixture, greatly increasing the expense to use LED fixtures at the same brightness level as with traditional incandescents.

See also

Wikimedia Commons has media related to LED stage lighting instruments.

• Solid-state lighting
• LED lamp

References