HERE are two school concerts, separated by more years than I care to remember.

How does it happen, that time thing? One minute you are a long-haired teenager playing in a school concert; the next - give or take a decade or three - and you are a middle-aged baldie watching your long-haired teenage son playing in a school concert.

Both musical occasions feature guitars, but that's where the similarity ends.

My spotlight moment involved a solo piece for classical guitar, followed by a threesome with my guitar teacher and another pupil. Looking back, everything went off all right, although the nagging thought now arises of parents sitting there thinking, "Well, he's not exactly Segovia, is he?" and wondering what they were missing on The Sweeney.

That's enough about my concert career, which didn't progress much further. The classical guitar was abandoned in favour of making things up and musically farting around, which pursuit entertains me still, especially when experimenting with open tunings (DADGAD anyone?).

While I fiddle on my acoustic guitar, if that's not a musically mixed metaphor, the 14-year-old is up in his attic bedroom, blasting out songs on his electric guitar, scaring any passing pigeons and possibly the neighbours too. The lad is perfectly obsessed and is already much better than I ever was.

All those hours of lessons, playing and practice, all that broadband surfing for the music of favourite songs to play, came to noisy fruition on Tuesday at the Joseph Rowntree School Easter Showcase.

I've been to a few of these affairs and the first half went as expected. The swing band played, and they are always good; the choir sang four songs beautifully; there was an impressive piano solo composed and played and by a sixth former; a tiny flautist did a sparkling turn; and so on, all to happy effect.

After the break, the pattern was broken as three school rock bands had a spin, starting with the Year 9 band in their concert debut.

As the family guitar hero fiddled with his leads and kept his audience waiting until his guitar was working properly, I thought back to a seven-year-old whose hand couldn't make chord shapes. He got so frustrated when I showed him what to do, so cross that he couldn't manage it straight off; and, now, there he was, up on a stage, with girls hollering and shouting out his name.

That didn't happen when I played my stuffy little classical piece. In fact there probably weren't any girls in the audience at all, what with it being an all-boys' grammar school (and there's a good way to mix up a boy about girls, but that's another story).

The girls had been shuffling their chairs and nattering earlier on, annoying the audience. Now they were rock fans and it didn't seem to matter, especially as no one could hear themselves think.

The band played Sweet Child O' Mine by Guns N'Roses. The offspring flung out his solos, sweet and loud. Pride swelled and I rubbed my eyes once or twice.

There he was, up on stage, pulling off what I always fancied doing. In a sense he was fulfilling my fantasies, except he wasn't - he was fulfilling his own, which is much more important. He gets to play on stage and I do what I do, which is to watch and write about it later.

Two more rock bands played, there was a reggae composition, some great Ghanaian drumming, and then the swing band returned (no Birdland this time, what a shame).

The audience comprised the usual willing suspects, the mums and dads, with grandparents in proud tow. It was funny to see them all - to see us all - sitting on stackable plastic chairs in the vaguely down-at-heel hall while rock music blasted the dandruff from the top of our heads. I'm sure those amplifiers were set all the way to 11.