Two years ago, a special opera bus ferried audiences around to see cutting-edge music theatre in a chilly barn, a far-flung lighthouse and a city-centre flat. Last year, a weekend of microtonal music tweaked and stretched the ear with bewitchingly out-of-tune sounds from the Middle East and northern Scotland.

You could never accuse Aberdeen’s sound festival of contemporary music of lacking ambition – nor of failing to entertain and provoke in equal measure. If you want a good guide to what’s fresh and thought-provoking across a broad spectrum of more serious new music – yes, with classical at its core, but bringing in jazz, world, electronica and more – the three-week splurge in Aberdeen and nearby towns is the place to be.

And this year’s theme – new approaches to traditional music – looks set to continue the festival’s liking for big, thought-provoking themes. ‘But there’s absolutely no link to the referendum!’ says organiser Fiona Robertson. ‘We started planning events before the referendum was even announced – and there’s only one piece that’s even referendum-linked.’

That’s the aptly titled 'Independence' by Glasgow-based composer John De Simone, to be performed by Glasgow new music group Ensemble Thing in Aberdeen Art Gallery, and there’s a personal perspective on the debate: De Simone’s grandfather, John MacCormick, was one of the founders of the Scottish National Party, and the piece deals with Scottish cultural identity in the modern world of mixed nationalities.

And although there’s other Scottish music in the programme – folk singer/guitarist Alasdair Roberts collaborating with creator of bewitching electronic soundscapes Ross Whyte is another highlight – the festival looks far beyond these shores for its trad explorations. To Nordic neighbour Norway, for example, with Hardanger fiddler Britt Pernille Forholm collaborating with Scottish fiddler Sarah Jane Summers on ambient digital soundscapes. Or to Turkey, where harpist Şirin Pancaroğlu works with Erdem Helvacioğlu on electronics to meld Turkish classical, contemporary and electroacoustic music. Or even to Argentina, where foursome Fulgor al Bies create some idiosyncratic sounds using traditional instruments, including bandonéon, sax and piano. ‘I’m not sure to what extent any of it is going to sound like anything you’d expect traditional music to sound like,’ admits Robertson, ‘except that it’s on traditional instruments. But it’s about taking traditional sounds, working with them and turning them into something newer and more innovative.’

One particular stand-out trad event should be Breton piper Erwan Keravec showcasing new music for bagpipes – in collaboration with classical cellist Rohan de Saram, and also with vocal improvising group Vox. ‘He’s commissioned all these major European composers to write new pieces for bagpipes,’ explains Robertson, ‘and heaven knows what it’s all going to be like.’ His events are complemented by an open-air performance by Argentinian composer Fabiana Galante, local pipers, saxophone and electronics in Aberdeen city centre – sure to draw a crowd.

In Robertson’s words, the festival’s trad stuff might be ‘all a bit quirky’, and it’s hard to disagree. And while she’s keen to stress the breadth and diversity of the event’s content, she’s not neglecting the more classical side either, with an opening performance from Scottish percussionist Colin Currie, and visits from the Scottish Ensemble, Red Note and Mr McFall’s Chamber. ‘It’s not really a hardcore new music festival – it’s a bit gentler,’ she explains. ‘It’s very much about trying to bring new audiences in, but we also want to give Scotland somewhere where exciting, innovative contemporary music can be performed.’

And in its tenth anniversary year, Robertson feels like the sound festival might finally be growing up. ‘We started off as a tester weekend in 2004, and suddenly it’s grown into this monster,’ she says. ‘Now, we’re in a very different place – we’re talking to other festivals internationally, we have people offering us performances, and we ourselves also have new ideas and partnerships we’d like to explore.’ Those international collaborations have borne fruit in a partnership this year with the Musiques Démesurées festival in Clermont-Ferrand, central France, which brings together the Orchestre d’Auvergne with the Red Note Ensemble in one of sound’s largest-scale events.

But although it’s grown, Robertson is keen that the festival has lost none of its intimate charm. ‘I don’t wander round being a grand festival director – well, I don’t have the time!’ she says. ‘We try and have a relaxed feeling in the festival, and it’s all about getting down and dirty, and mucking in. We try to get as close to our audiences as we can. It’s not just about coming and seeing a concert and going away again – it’s about interacting with the musicians who are here, meeting the composers, getting involved. That’s all part of the experience for us.’

sound festival, various venues across Aberdeenshire, 23 Oct–10 Nov.