huddled as they are behind the barricades of musical snobbery, fiercely defending their tiny patch of credibility . . . there was a time when jazz and pop music were the same thing.

Those were the days when big bands ruled the earth, or at least the musical part thereof. This was the music's golden age, during the '30s and '40s, when jazz was dominated by 15- to 20piece bands, led by musicians like Claude Thornhill, Stan Kenton and of course Duke Ellington, who toured incessantly, performing every night for large audiences eager to dance.

The reason they were big, of course, was to make a sound loud enough to reach the back of a dancehall full of couples with other things on their minds. The big bands made a commensurately big sound and some, like Count Basie's orchestras, were famous for the sheer impact they had on listeners. After the war, things changed. Amplification meant that a small group could achieve the same volume as an acoustic big band. The economics of keeping a big band on the road became unworkable. And anyway, by the mid-'50s, the dancers were looking for rock 'n' roll played on electric guitars.

The era of the big band came to an end and small bebop groups went on to lay the foundations for modern jazz.

But what is missing from the experience of a small group, however talented and however loud, is the visceral excitement of sitting in front of a full section of horns and hearing them blast out wide sheets of pure harmony.

There are few musical thrills to compare with a live big band, though opportunities to seek such thrills are now rare. Rare enough indeed to make tonight's visit of the UMO Jazz Orchestra required viewing for anyone who wants to know what a good big band really sounds like. The UMO hail from Helsinki where they are funded . . . in a far-sighted move that should be noted by those interested in developing Ireland's musical community . . . by Helsinki's municipal authorities, by the Finnish Broadcasting Company and by the Finnish Ministry of Education. Their support has enabled the UMO to become the prime catalyst in what is a vibrant Finnish jazz scene and, like the big bands of old, it has been a creative hot house, nurturing the careers of most of Finland's leading players of the current generation.

Along the way, the UMO have attracted the world's leading jazz players as guests, including legends like Dexter Gordon, Joe Henderson and Dizzy Gillespie, and their guest leaders have included masters of the modern idiom like Kenny Wheeler, Gil Evans and Maria Schneider.

They arrive in Dublin tonight for a one-off concert, organised by the Improvised Music Company, in the O'Reilly Theatre on Great Denmark Street, Dublin, under the baton of Kirmo Lintinen, with music from composers like Eero Koivistoinen and Jarmo Savolainen. It will be a rare opportunity to see this rarest of beasts in its natural habitat and no one who loves this music will want to miss it.

Meanwhile, the Improvised Music Company's new agent programme for the indigenous scene, IMC Artists, started in the best possible style last week with a showcase concert in the Project arts centre. Restricted alas to an invited audience, nothing could have better made the case for the new venture than the quality of the music. Over two nights, 10 of Ireland's finest ensembles, ranging from duos to a 10-piece "little big band", gave ample proof of the raising of standards in Irish jazz over the last decade and IMC's timely intervention, which proposes to represent these musicians to bookers and promoters around Ireland and further afield, marks a new era for such music in this country.

Good luck to them.