MacDonald knows about improvisation. He’s been making it since the 1990s as a saxophonist, including as a founder member of the Glasgow Improvisers’ Orchestra in 2002.

His musical CV reveals an ongoing series of collaborative performances documented in some 60 recordings. As an academic music psychologist, focused on the relationships between music, improvisation, community and health, he’s written papers and even given a TED talk. Lately he has documented exploratory interactive collaborations with an AI avatar in his 2023 book Conversations with Chimère. The one thing he hadn’t done – until now, that is – was make a solo improvised recording, possibly because of his conviction that improvisation is fundamentally a social and collaborative process.

Envisaging it as a collaboration with producer Richard Youngs, however, persuaded him that ‘even a solo is social’ and thus the three tracks on Desire Lines were achieved. 'Track 1' is based on a single breath lasting 21 minutes, a relentless downhill ski run combining babbling alto sax arpeggios and slapping pulses in an adrenaline-fuelled counterpoint until MacDonald finally collapses into laughter.

'Track 2', recorded on soprano “just a quick glug of water” after the first, has the feel of an ethnographic recording with breathily fluted melodic phrases evolving over a similar pulsing root. 'Track 3' is an exploratory journey of the instrument itself. It’s classic free blowing stuff and an obvious reference point would be the great Lol Coxhill, one of MacDonald’s many past collaborators.

They may be short of the kind of melodic richness and rounded tone Macdonald is known for, but nevertheless the engaging post-minimalist structures underlying the pieces as they evolve gives them hypnotic depth.