GYORGI Ligeti was one of the 20th century's most distinct musical voices, and his was a voice that was always up and changing.

He famously remarked: "I cannot understand this idea you have of avant-garde, and this post-modern neo-tonal stuff, as if these were the only two possibilities and there could be no third way. There are always a hundred ways. You have to find them."

Ligeti hated dogma and seemed to reposition his aesthetic goalposts every time he wrote a piece. Born in 1923, a Hungarian Jew in what was then Romania, he studied and lectured in Budapest until 1956, when he fled to Austria under cover of a postal train. He took refuge at Stockhausen's electronic music studio in Cologne, lived stints in Berlin and Hamburg and finally settled in Vienna until his death in 2006. Familiarity with exile and political oppression seems a likely factor behind his faith in artistic individuality.

This week and next, the Scottish Chamber Orchestra and its principal conductor Robin Ticciati turn their attention to Ligeti's music. They perform the 1970 Chamber Concerto for 13 Instruments Soloist alongside music by one of Ligeti's heroes, Brahms, and the Hamburg Concerto, an extraordinary late work only fully completed in 2002, alongside Dvorák's Fifth Symphony. Pre-concert talks and a study day led by Ligeti scholar Michael Searby beef up the learning potential with historical context and gentle musical analysis.

SCO principal horn Alec Frank-Gemmill, pictured, is soloist in the Hamburg Concerto. Anyone who has heard the orchestra since he joined at an unreasonably young age in 2009 will recognise his distinctive sound and musical intelligence; Frank-Gemmill is one of the most exciting horn players of his generation in the UK, and the concerto spotlight is well deserved.

Over the phone from Amsterdam, where he was guest performing with the Royal Concertgebouw Orchestra, Frank-Gemmill explained his particular connection with the Hamburg Concerto. "It was written for my great teacher Marie Luise Neunecker," he says. "She's the most famous horn player in northern Germany; Ligeti taught in Hamburg for years and knew her playing well. I feel her whole approach to music is encompassed in this concerto's sound-world.

"In my final lesson with Professor Neunecker she handed me the manuscript of the Hamburg Concerto. 'We've been working together for so long,' she told me; 'I want you to have this.'" Frank-Gemmill says that working from Ligeti's hand-annotated score has revealed key detail – scribbled changes to tempo and dynamics that subtly but significantly alter the texture of the piece.

Ligeti was fiendishly demanding of his musicians, and this concerto is no exception. Its solo writing specifies intricate fingerings to make the instrument sound perversely out of tune, while a support contingent of four olbligato horns provides sometimes foggy, sometimes squealing microtones as backdrop.

"It's hyper modern, all those harmonics and microtones," says Frank-Gemmill. "Yet because it's written for horns, an instrument that has fascinated composers for centuries, there's an antique feel to it too. The whole effect sits somewhere outside of real time.

"Ligeti reinvented himself every 15 years or so. Part of that was just a freak of history; everywhere he went he was persecuted. But even at the end he continued to experiment. If there's one thing that defines his music, it's that he always transforms his content into something unique. Here he pushes every limit of what's possible on a horn."

Ligeti himself called the out-of-tuneness of this piece "weird", which Frank-Gemmill reckons is a roundabout way in for listeners: "Weirdness can be off-putting in contemporary music – it disarms people, makes them feel like they're not understanding something. But if it's supposed to be weird? Then you can relax, confident that you're getting it exactly right!"

Ligeti took time over the Hamburg Concerto, adding movements (there are seven in all) as and when they came to him. In general he composed this way, without rigid structural plans, work taking form along the way. It was a freedom of expression without imposed boundaries.

Ticciati has said that he was keen to programme Ligeti in order to stir up a reaction from the SCO audience – an aim Frank-Gemmill supports. "The horn concerto is shamelessly out-of-tune and incredibly noisy at times. So yes, plonking it in a programme alongside Dvorák's Fifth Symphony is a shock tactic of sorts. It will provoke a way of listening that is open and alert."

Though we've heard Ticciati conduct modern repertoire –including Ligeti's Piano Concerto – during his three years with the SCO, so far we've known him mostly as a romanticist. Frank-Gemmill suggests that association has to do with body language as much as repertoire: "Robin is very generous in his gestures and gets an unusually rich sound from the orchestra. There's a freedom in his approach that he doesn't change when he conducts contemporary music. I think that's incredibly brave.

"Working on the Hamburg Concerto with him has been a real ear-opener for me. Robin reminds us that no matter how preoccupied we are with clarity and getting notes in the right place, we have to bring the music to life."

The SCO and Alec Frank-Gemmill perform Ligeti's Hamburg Concerto at City Halls, Glasgow, tonight and at Edinburgh's Queen's Hall tomorrow. Next week they perform Ligeti's Chamber Concerto for 13 Instruments in a programme that also includes Brahms's Second Piano Concerto with soloist Pierre-Laurent Aimard. This Sunday, Dr Michael Searby leads a Ligeti study day at Stewart's Melville College in Edinburgh – tickets via SCO onlne.