MIDI has been with us for around 10 years, and most modern musicians are familiar with its basic application. Sequencing and editing music by computer is a commonplace activity — but have you thought about controlling your own light showas well?

The potential for such control has been extended by the recent adoption of the MIDI Show Control specification. This is basically a powerful set of System Exclusive commands that enable different lighting products to talk to each other. Unfortunately it will probably be quite a while before we see keyboards integrating this with their own specifications, but existing technology still allows MIDI control of lighting.

For example, you can send patch changes to a MIDI equipped lighting controller. If you were using a Roland A80 master keyboard, which can send four extra patch changes in addition to those it sends for each zone, you would then be able to switch four separate lighting units. Note on/off messages can also flash lights on and off, enabling you to effectively 'play' your own light show. You could use a spare track on your sequencer to send cues to a MIDI-equipped lighting desk. The lights would then change at the same time as the song went into the chorus, for example.

Many sequencer packages allow you to define sliders and switches. When connected to a lighting controller that has suitable MIDI capabilities,you could control the lighting levels just as you would MIDI volume, panning etc. Perhaps the greatest advantage of using a sequencer to control your light show is that you can edit it just as you would edit the music for a song, although you will obviously have to work within the limitations of your hardware.

Whilst you're doubtless quite familiar with MIDI and its conventional music applications, MIDI equipped lighting controllers are probably new, so let's take a look at examples of such units.

A LOOK AT SOME HARDWARE.

Pulsar Lighting of Cambridge are a company who have included MIDI within several of their products. The Universal Interface, for example, is a 1U rack mount unit which translates MIDI and other serial data into 0-10V signals intended for a dimmer pack. 36 independent channels of voltage levels can be derived from MIDI note and velocity information. If your computer has an RS232 serial port, you could connect it directly to the Universal Interface without having to go via MIDI.

Note Off (and Velocity Zero) messages can be filtered out so that when the channel is triggered, the channel voltage (and therefore brightness of that channel's light), which is proportional to the MIDI velocity, is 'latched', and will not drop when you release the note. Although the unit can control up to 36 dimmers, you could start out with just six, and add more when required.

The more ambitious user might choose Pulsar's Masterpiece 108. This is a powerful 19" rackmount lighting control desk with 108 channels, 216 scenes, 54 scene chases and 48 "environments" (this terminology is the lighting world's equivalent of the bars, patterns and songs we are used to in our beloved music sequencing programs). With this system, all the sequencing and dimming of individual lights would be carried out by the Masterpiece, and you would use MIDI program changes to trigger scene changes at appropriate points in your song/show.

Groove Electronics are a company familiar to many musicians through their range of MIDI retrofits for classic analogue synths and drum machines. However, they also make is a neat little box called the MC Lite. This is not a dimmer, but enables you to switch lights on and off via MIDI. 16 channels are catered for, and the unit has built-in preset sequences. Two MIDI Ins are provided, one for individual light control and one for MIDI docks, so you can step through presets. You can also select Presets with program change messages, or assign note numbers to each light and play them from a keyboard.

In the world of big tours, the Varilite is one of the leading products. This is an intelligent light that can rotate, change colour, change pattern, and perform a host of other tricks at the same time. All this is controlled over a high speed digital network by the Artisan lighting console, which really does look like something out of Star Trek. Needless to say, a skilled operator can produce amazing results with Artisan and a bunch of Varilites; but where does the humble MIDI interface come into the picture?

Varilite developed the MIDIport for their Artisan controller just over a year ago. At that time MIDI Show Control had not been developed, so the basic function of MIDIport was to trigger the main playback keys of the Artisan via note on/off information. Varilite also developed their own cue sheet program for the Atari, to enable automated triggering of the console. This is often used for such things as new car launches, where music, light and movement have to be synchronised. This is achieved by having the music on a SMPTE-striped tape. SMPTE is converted to MIDI timecode (MTC) in the Atari, and the Atari then sends cues to the Artisan console, which steps through its lighting program. For Varilite, this is the most practical approach to MIDI control at present. MIDI would be too slow to directly control Varilites, as each light has 15 separate functions,and the Artisan desk can control 1,000 channels!

MIDI CONTROL IN A LIVE SITUATION.

On the Australian leg of the Roxette tour, MIDI was used to help simplify some of the Varilite sequences. The keyboard player's sequencer was used to trigger changes on the Artisan console, so the Varilite operator was free to concentrate on the timing of manual cues. David Bowie's Sound and Vision tour also featured MIDI in an innovative fashion, combined with SMPTE, video and 35mm film by Robert Montgomery and Nocturne Video of San Francisco. At the start of each song, the keyboard player's sequencer would send a song start message to a Lynx module, which in turn sent SMPTE to various video machines, one of which then took over synchronisation. 35mm film was also locked up using a specially developed piece of hardware.

Theatre Projects are another company who are using MIDI to combine sound control, slide projection and lighting. They are often required to produce a show where light movement and sound follow each other. MIDI controlled delay lines are connected to a multi-channel sound system, which enables sound to be panned around in sync with the lighting.