The system couldn't be simpler but the programming can be as sophisticated as you like. Ian Masterson gets a taste of the bright lights...

As a relatively recent phenomenon, MIDI lighting interfaces are still something of an unknown quantity for many people. Having made the decision to get involved in lighting, what most people want is a simple, perhaps expandable unit that relates directly, via MIDI, to what they produce musically.

For those who perhaps already have a sizeable lamp and effects rig driven off traditional mains dimming packs and who fancy using their sequencers to control the lights via MIDI, the best bet would probably be something along the lines of Pulsar's Universal Interface (see review in last month's MT). This sort of device will translate MIDI note and velocity information into the industry-standard 10-volt analogue control protocol used to operate lighting packs.

If, however, you are new to the world of computer-operated lighting and have decided to start with a small, portable system and work upwards, you could do a lot worse than to include the MP820 on your shopping list. A single, small black box that simply converts MIDI information directly into mains voltage, the MP820's only distinctive features are two Bulgin socket outlets, a MIDI In socket, nine LEDs and a strikingly substantial blue mains lead!

Your computer is hooked up to the single MIDI In socket and your lamps to the twin Bulgin connectors. The circuitry can handle eight channels of lighting at any one time, up to a maximum current of 20 amps (hence the substantial mains lead). Each of the eight lighting channels corresponds to a single MIDI note - so if you set the MP820 to recognise MIDI note C3 as the controller for the first lighting channel, it goes on to interpret C#3 as the second, D3 as the third - and so on. The higher the MIDI velocity, the higher the mains output - and the brighter the light. Simple, n'est-ce pas?

This of course means that you can 'play' the lamps from your MIDI keyboard, record the data on a software sequencer and then edit the various velocities to create all manner of crossfades, flashes and er... groovy effects. Since the MP820 can respond to eight notes on any single MIDI channel, you could theoretically add more and more MP820s as your system grows: 16 units on a single MIDI channel giving 128 channels of light; 16 units on each of 16 MIDI channels giving an incredible 2048 channels.

The only design niggle which came to my attention with the MP820 was the location of the MIDI channel and note setting switches. Basically, you have to get your screwdriver out and remove the front cover to access the tiny DIP switches on the PCB inside. A set of external rotaries would have been much nicer, and worth the extra expense.

Interestingly, the MIDI implementation stretches beyond simple note (lamp) on/off and velocity (brightness). For example, control change #96 sets the fade rate at which the pack raises or lowers the brightness of the lights - so you can have instantaneous 'bursts', or slow fade ins. Also the 'all notes off' command acts effectively as an instant blackout control, cutting the power to all the channels.

In use, the MP820 is blindingly (sorry) simple: you literally just plug it in and go. The eight red LEDs on the top panel of the unit signal which of the lighting channels are being triggered, while the green LED signals that the mains power supply is healthy. Which leads me neatly onto one word of warning. Since the MP820 is rated at 20 amps, it will happily carry up to 4800 watts of power at any one time (to a maximum of 1200 watts on any individual channel).

Unfortunately, your normal 13-amp socket will not. So if you are simply planning to fit a 13-amp socket on the end of the mains lead, make sure the total lighting load on the MP820 doesn't go above 3000 watts or you could find yourself blowing fuses mid-gig.

Of course, if you are able to hook the MP820 up to a professionally-sourced, multi-phase lighting supply (such as those found in most theatres and decent venues), this restriction doesn't apply.

Aside from the minor niggle over the positioning of the MIDI controls, the MP820 is a rather well thought out piece of kit. The simplicity of its design imposes no real limitation on your creativity but will win it many friends amongst those still unsure of this relatively new arm of technology. Indeed, you can get pretty engrossed in some major light programming, particularly when using more than one unit.

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