Being at a jazz recording session isn't always unalloyed fun, but it beats the hell out of standing around on a film set waiting for the light to change or the star to analyse his motivation. I know. I've been on both, and give me jazz musicians every time. There's a basic irreverence about them - maybe it comes from being part of a demanding, iconoclastic music which has had, for most of this century, to fight for some small place in the sun. In those circumstances, a sense of humour is a considerable asset.

It also helps when things get edgy in the studio - as they were, late one afternoon a few weeks ago, in The Works, Paul Ashe Browne's recording studios in Upper Grand Canal Street. Outside, it was a rare day this summer - hot and humid. Inside it was hotter still, with 10 people crammed into the control booth listening to a playback. Mostly things had gone well that day, but the heat and hours of playing had taken their toll on lips, stamina and saintly dispositions - and there was still more to get "in the can" for producer Ronan Guilfoyle to keep things on schedule.

For TIME - The Improvised Music Ensemble - that schedule was tight if they were to have their debut CD ready for launch at the opening of the Dublin Jazz Week, less than a month away. But not impossible; weeks of rehearsal had the octet well prepared in the original material, specially commissioned for the band, that would be on the album.

When I got there the dissatisfaction with the last take, on a slow, exposed arrangement, was palpable, and Guilfoyle had to decide whether to persevere with that piece and risk staleness, or worse - eight people with homicide in their hearts, perhaps - or defer it for the moment and go on to something else. He opted for a faster, more extrovert, straight-ahead piece; the change of pace would ease the tension and lift the band. He also had another pressure. "I have to get Sostenuto" - the quicker-tempo item - "and the first movement of the suite done tonight," he said.

"My lip's too tired to play quietly," said trumpeter Mark Bradley, still thinking of the slower piece.

"Do some kissing. That relaxes your lips," recommended trombonist Karl Ronan, who obviously knew a thing or two about embouchures and osculation.

"Well, look elsewhere, mate," said Ronan Guilfoyle.

Grinning, the band filed back to their places. Bradley, Ronan and the reeds - Michael Buckley, Jim Farley and Gerry Godley - vanished behind the screen cutting them off from Conor Guilfoyle's drums, Justin Carroll sat at the grand piano in a separate, glass-fronted booth below the drummer, and bassist Michael Coady retired to another booth in solitary splendour.

Of the octet, only the drummer could see everyone else in the band; he was also the one most readily visible from the control booth. Then it was headphones and the first take of Sostenuto, one of two compositions by Ronan Guilfoyle scheduled for the album.

It was a beautiful take, over eight minutes long, with a lovely alto solo by Farley and fine trumpet and bass spots. "It felt good," said Ronan Guilfoyle. They went for another, with Carroll coming up with another lovely intro, completely different from the first, yet just as much to the point. There was little to choose between it and the first - a wrong note from piano behind the trumpet solo and a slight problem with the trumpet on one of the ensembles.

Mark Bradley suggested a third take. "Everybody up to it?" he asked. They were. Another delightfully fresh intro from piano, a marginally faster tempo and a take that got the thumbs-up from the producer. Sostenuto was in the can.

The atmosphere was notably more relaxed as they discussed the first movement of Sundials, a four-part suite, also by Ronan Guilfoyle, which was to be the last recording of the day. "Karl," said the producer. "Remember you said I couldn't write anything you couldn't play? You're about to prove it." He turned to me. "It's written to show off the abilities of the band," he explained. "It's very virtuosic." Then he switched back so that he could talk to the band. "Don't forget, if you make a mistake, don't stop unless it's disastrous, because we need a good rhythm take."

Without being definitive, the first take produced what he called a "basic track". A couple of takes later, some discussion about a segment of the trombone solo and a problem with the ensemble that preceded it, which had to be redone, and the remaining targets for the day had been achieved.

Late the following day, with the rest of Sundials OK, the atmosphere was relaxed enough for some impromptu musical send-ups by the band while they were waiting to tackle Winter Waltz, one of the loveliest pieces planned for the CD. Written by guitarist David Whyte, it makes good use of the octet's range from top to bottom. It's also a tricky piece, with a rhythmic interlude of the kind that used to be known as stop time, that must have been nerve-wracking to do.

A couple of tentative openings, then a complete take. A second take, and the trombone solo got a thumbs-up from Ronan Guilfoyle. "Great solo, Karl, especially the entry on the second chorus. Take clotted cream."

"I'm not actually sure whether you're insulting me, or complimenting me," said the trombonist.

"I'm complimenting you, for a change. Both solos are great," answered Guilfoyle.

Some ensemble unevenness was identified on the rhythmic interlude, involving bass and piano. The parts were redone until the producer was happy. On the retake of the piano intro, Guilfoyle spotted something amiss. "Stop it. There's a wrong note there," he said.

"I'm sorry," answered Carroll. "I'm just playing it as written."

"Just change it 'til it sounds right."

He made the change. "Yeh, Justin, that's it," said Guilfoyle.

"Are we kosher?" asked Paul Ashe Browne anxiously. It was getting late.

They were, but the producer was already thinking ahead to the next step in the recording process - the tiresome but necessary job of mixing, where adjustments of balance and sound are made. "Each instrument needs to be looked at individually and made less hard. The group needs to be more like on stage," he said, as he and the engineer discussed the spread in the mix.

"All that stuff is natural to me," said Paul Ashe Browne. "The only thing might be to warm it up in the valve department."

"Then a nice reverb on the band," agreed Guilfoyle.

The musicians were already packing their instruments. Jim Farley was doing an ET - phoning home to say he would be there in half an hour. A couple of the others were heading off to gigs. The rest were for adjourning across the road, a few well-earned pints to savour the satisfaction of a job well done, and maybe catch up on the latest Bill Clinton jokes.

In Kitty O'Shea's, opposite, the music was more ethnic. A couple of Irish-American tourists, loosened up by the local brew, were letting everyone know that jigs and reels being played were their roots. I don't think the irony struck any of the jazzmen.