MIDI: 30 years old... almost
Auntie causes premature eulogisation?
Despite rumours to the contrary , MIDI is not 30 years old today. The concept is older and its actual adoption as an industry standard gets its birthday next summer. Yet as industry standards go, it’s certainly been a robust one.
As with a lot of technology standards – remember draft-n Wi-Fi? – manufacturers don't want to hang around waiting for the ink to dry on a specification, and MIDI pioneer Sequential Circuits stole a march by introducing its Prophet 600 synth  with MIDI interfacing around 30 years ago in December 1982.
But the actual MIDI 1.0 specification wasn't published until August 1983, and even the MIDI Manufacturer's Association (MMA), along with the Audio Engineering Society (AES), won't be blowing out candles until next year. It'll be celebrating at various events throughout 2013 starting with the NAMM  show.
In its most basic use, the Musical Instrument Digital Interface took the pain out of linking synthesisers and controllers - keyboards and the like - together. Previously, patchbays of CV (control voltage) and gate (trigger) connections were used to determine pitch and note duration respectively enabling electronic music gear to talk to each other. It worked, in a rudimentary fashion but tuning, among other things, was frequently a problem with these analogue devices.
By contrast, MIDI was much more sophisticated even though its actual physical interface seemed somewhat archaic: it used the five-pin DIN plug that most of us had previously discovered on the back of unfriendly European hi-fi gear. The same interface is still used today and even though the various MIDI protocols have been added, the standard has endured such that music gear produced since MIDI’s mainstream introduction, some 30 years ago, can still be brought to life alongside state of the art equipment by simply plugging in one of those DIN cables.
Indeed, the hallmark of original MIDI gear would be the presence of In, Out and Thru interfaces – the latter being a pass through port. Not all of these interfaces were needed – so a dumb controller keyboard wouldn’t have an In port, for instance. Nowadays, USB is frequently added instead for gear that’s intended for use with a computer, bypassing the need for a separate MIDI interface altogether. But that's just the physical interfacing side, MIDI is much more than that.
The standard defined that asynchonous data sent along those cables should run at 31.25 kilobaud – a 10-bit signal with one start bit, eight data bits and one stop bit. MIDI features 16 independent channels which enabled simpler daisychained configurations to work with different devices set to different channels or even the same channel for layering of sounds. Later, computer sequencers would take full advantage of the multichannel functions allowing musicians access to a range of sounds to build upon.
The resolution of MIDI’s various Channel Message formats meant that you’d get 0 to 127 on everything, for notes this allowed for around 10 octaves. Yet MIDI did more than just deliver note data and pitch bend twiddling – velocity (how hard you hit the key) was featured too, enabling more expression than now you hear it now you don’t. By using Program changes, a synth could be instructed to go from say, a strings preset to a brass section. Hence, your hooked up gear was not just permanently fixed on one setting but could be remotely switched in real time.
Control change messages allowed other aspects to be altered such as volume or even delivering sustain pedal functions for keyboard players. Indeed, the utilisation of these message types have since been incorporated for use in lighting rig control desks.
Early MIDI demonstrations didn’t necessarily have all these refinements – and there are plenty more features to discuss and many more added since – and indeed we will look at the evolution of MIDI next year when we really can say happy birthday to its official adoption as a standard, rather than its first appearance on a Sequential Circuits Prophet 600 synth.
In the meantime, I’ll be dusting off my Atari 1040STFM and hoping that my C-Lab Creator floppies will work, as I trawl for buried treasure and pump Eighties pop patches of System Exclusive data into my trusty Yamaha TX7 to make it dance again. ®