Folk and jazz: As the final note to an illustrious career rings out, harmony remains

The sixth of October, 1964 - Ian McCalman can pinpoint it as precisely as that: "We were all in the same studio, virtually next to each other. Derek was humming and I said, 'Oh that's a folk tune' and he said he sang at The Elbow Room in Kirkcaldy. I said I had a Levin guitar, same kind as the Corries, and Hamish - con artist - said he played folk music and had this whistle..."

The three decided they'd practice for a year before going public. In fact, within a fortnight they found themselves and their two-song repertoire booked for a 30-bob spot in what was then Edinburgh's folk pub, The Waverley. Some 6,000 gigs and 28 albums later, the renowned close-harmony trio will play a short set at this Saturday's MG Alba Scots Trad Awards bash at Perth Concert Hall, and an already sold-out final farewell concert at Edinburgh's Queen's Hall on 10 December, which will be filmed for DVD.

The rest is not quite silence, however. Ian McCalman, now 64, may be "retiring", but continues to run his recording studio, Kevock Digital, at his home in Lasswade, Midlothian. The remaining "Macs", Nick Keir and Stephen Quigg, will continue performing solo and as a duo. Keir replaced Bayne after the latter left "in a rare fit of sanity" in 1982 to make concertinas, while Quigg joined after Moffat's untimely death from cancer in 2001.

The award-winning group's powerful triple-voice delivery of traditional and contemporary material - "full frontal vocals", as McCalman calls it - has remained their hallmark over more than four decades. Perhaps it was that constancy which prompted what he regards as poor treatment from the Scottish media. "A lot of the media - though not the people who came to see us each week - got this idea that the McCalmans were doing nothing but Willie's Gone to Melville Castle all the time." He apologises for "sounding like a grumpy old man... But it was only when we went to Denmark and Germany that we actually started getting good reviews."

For McCalman, the song's the thing. Ask how the folk scene has changed since the early days, when the idea of the forthcoming high-profile Scots Trad Awards would have seemed improbable, to say the least, and he tempers admiration for the new waves of formidable young musicians with concern that songs risk being swamped by instrumentation: "Don't get me wrong.

I'm in awe of these instrumentalists," but, he adds, name-checking singers such as Karine Polwart, Julie Fowlis and young Siobhan Miller - "They've so much to give, but I worry they'll get lost within a group and instrumentals take over." The McCalmans, he reckons, were lucky - in finding each other, in landing their first recording contract with EMI's old Waverley label in 1968, in the Combined Services Entertainments engagements that had them singing to troops as far apart as Oman and Belize. On their own tours, the Macs and Denmark took to each other in a big way. McCalman, whose wife, Ellen, is Danish, recalls breathlessly phoning his parents in the late Sixties after a rewarding gig in Aarhus to tell them how much he'd made.

He talks warmly of those heady early years: "Almost coming to blows during practices over the harmony of one syllable... or coming back from the Waverley bar, after singing all night, we'd just stop in the High Street and sing a new song just for the sound."

As he speaks, he's waiting on musicians to arrive at his studio, where he is recording a tribute album to his friend, the singer-songwriter Davey Steele, who died ten years ago. It's due out on Greentrax in time for a "Steele the Show" Celtic Connections concert on 20 January, which McCalman, whose self-deprecatory humour was an integral part of the Macs' show, will co-present with Phil Cunningham. Retirement isn't getting him off the stage just yet. l See www.the-mccalmans.com and www.handsupfortrad.co.uk