Perhaps a song played on the radio, a new LP in a friend's collection, a live performance - out of the blue and always life-changing in more or less subtle ways. With me it came in a record shop in Bath when I was 15 or 16, quite young enough for new enthusiasms to arrive like steam locomotives.
A friend had heard a Hawkwind album at a mutual friend's house, and had been suitably blown away, although that idiom hadn't quite been coined by then possibly. We gathered up friend No. 3 and tore down to Milsom's record shop, and all crammed into one of those listening booths that shops had to make room for in those days. The "lift-off" at the opening of "In Search of Space" bubbled and soared out of the stereo speakers (better tech than any of us had at home, by the way), and I was never the same again.
Now, before the reader despairs of us, I know what most people think of Hawkwind! And I'll allow that they certainly went off the boil a bit around '74, by which time I'd seen them twice in concert. But I still have the feeling they were really on to something in those early days, particularly in their use of electronics.
Tape and razor blades
And here's where the life-changing bit comes in. Since the 60s I'd been intrigued by the new sounds that experimental composers were producing in their labs crammed with oscillators, filters and tape decks. And of course the BBC Radiophonic Workshop, staffed by innovators like Daphne Oram and Delia Darbyshire, the genius who realised Ron Grainer's Doctor Who theme by splicing it together note-by-note with tape and razor blades!
By the late 60s, Dr Robert Moog had perfected the synthesizer, integrating those disparate physics-lab devices into what could at last be called a musical instrument. I say "perfected" advisedly: although synth evolution continues apace, working Moogs from that period fetch a cleaning supervisor's annual income, and only in part for their rarity!
Intrigued, though not yet "blown away". That was to happen that day in Milsom's listening booth. What I heard was not something assembled from bleeps on tape and found-sounds knocked together in the lab, but an ethereal, organic-sounding performance.
The abstract whistles, warbles and swoops were the cry of forest things on unknown planets, the crackle of cosmic dust, and the very Music of the Spheres, no less. Thus began my long lusting to own a synthesizer. They were prohibitively expensive in those days, and remained so as I made my way in the world as a young adult.
Rock stars had multi-keyboard rigs that always included a Mini-Moog, normally sitting atop the Hammond organ or the Mellotron. All that kit seemed forever out of reach to the average wage-earner.
It was the early 80s before affordable synths came on the market, and the explosion of British, German and Japanese synth-pop was one result. Less conspicuously, another was that I got my hands on a used Korg Mono/Poly, a Japanese machine richly encrusted with those knobs and switches I had dreamed of endlessly.
It was every bit as absorbing as expected, but a steep curve of the learning sort. Knobs marked "X-mod" and "Filter env" had to be twisted and understood.
Other machines followed, and were patched together to make ever more complex effects. You couldn't save your sound for reuse later: it may have taken hours to construct, so you had to record it quickly and move on. Because you'd never find it again! "Programmable" machines had appeared already, but were either not yet on the second hand market or were super-expensive.
Another thirty years on things are a little different. Entire studios exist in software, including highly effective "models" of Mini-Moog, Hammond, Mellotron et al. Apps equivalent to machines that cost as much as a car in the early 80s can be downloaded to your Fondleslab for £4.99. Others are free.
After my Milsom's epiphany, I had sought out any and all bands that used a synth. Their number was growing but it was still an object of suspicion for a lot of musos, even those styling themselves as being in the vanguard of new music. (It was too inorganic I guess. Although trees did indeed die to create a Moog, you could remove the wooden chassis and it would sound exactly the same!)
Since then, popular music has diverged into innumerable sub-sub-sub-genres, most of them predominately electronic. Orchestral film and TV soundtracks are more often than not synthesized. High-end orchestral samples, in terms of cash anyway, are the pro market equivalent of the heavy rig of the caped 70s keyboard wizard.
Electronic music is ubiquitous and constantly, joyfully evolving. New underground dance genres aren't everyone's cup of tea, but they're of consuming interest to me. (Although I do find hardcore industrial nosebleed just a little fatiguing to listen to.) In the late summer of my years I still can't get enough of those hitherto unknown noises.