Cottier Chamber Project 2016, Glasgow

It should have been a complete disaster. Not announcing your festival’s programme until barely a week before it started ought to have guaranteed that nobody knew about it – no press, no audiences, other plans made, other things booked.

But still they came. It’s testament to the Cottier Chamber Project’s now firmly established place in Scotland’s summer musical life – this is its sixth year – that even keeping audiences in the dark as to what was planned didn’t deter them.

That bizarre delay was down to questions over two major funders, artistic director Andy Saunders has explained. And it can’t have been helped by the new demands brought by the festival’s increasing ambitions, either, with BBC Radio 3 broadcasts for the first time this year, plus new international visiting ensembles, an expanded dance programme (they’d even managed to scoop Anne Teresa De Keersmaeker’s Rosas), and an expansion of venues from the festival’s home in the magically atmospheric, slightly delapidated Cottier’s Theatre to Glasgow University’s concert hall and cloisters, and elsewhere.

But those new elements made the festival feel bigger and bolder than ever, bracingly confident in its eclecticism. As in previous years, it was a staggering, somewhat bewildering collection of more than 50 concerts and events across three stuffed-full weeks, blending incoming soloists and Scottish-based musicians letting their hair down before the summer break. There’s an enormous amount of goodwill that keeps Cottier alive and vibrant – from performers and audiences alike, clearly – and which evidently ensures it all comes together magnificently despite any delays or hitches.

That goodwill was there for all to see in the early-evening concert on 7 June, which gathered a string sextet from principals of Glasgow’s two big classical bands – the Royal Scottish National Orchestra and BBC Scottish Symphony Orchestra. And on the strength of their glorious, voluptuous Strauss and Dvořák, they really ought to get together again. They felt like a chamber group that had been playing together for years, so responsive were the players to each other, and so effortless was their ensemble.

Their Strauss Capriccio Sextet was admirably clear and lithe, poised and sculpted rather than indulgent, with a gentle glow to the harmonies which the players gave plenty of time and space to make their mark. The Dvořák Sextet Op. 48 had a lot more gusto and vigour, appropriately, the players relishing the first movement’s sometimes abrupt transitions and delivering the witty second movement with gentle swellings. It felt like a truly special event: six players with little to prove, simply enjoying the chance to perform together, and to share the disarming directness of their playing with the audience.

Later that same evening came a blistering solo recital (well, almost solo) of Bach, Boulez and a brand new piece, all from violinist Alexander Janiczek (pictured above, with Aidan O'Rourke), currently associate artist with the Scottish Chamber Orchestra. The Bach was the solo Sonata in A minor, and by the end it felt like Janiczek had really taken us on an exhausting (in a good sense) journey, with each movement strongly differentiated, from the unforced cleanness of the opening Grave to the effortful, rugged second-movement Fugue. His Boulez Anthèmes was fantastical and lyrical, almost nonchalant, full of mercurial elegance even among Boulez’s fearsome technical demands.

It was the new piece, sadly, that disappointed. The festival had commissioned a work from folk fiddler Aidan O’Rourke, one third of trad trio Lau, but the resulting Opticks (for which Janiczek was joined by Ela Orleans on electro-acoustics) just felt too long and too episodic to be convincing. Inspired by the stained-glass windows in Cottier’s Theatre, it felt like a collage of ideas, including what was virtually a passage lifted wholesale from Arvo Pärt’s Fratres. Opticks only seemed to find its feet in a folk-like melody near the end, even if the whole thing was dispatched with bristling conviction by Janiczek.

Jumping forward a week, two more concerts showed just what a thrillingly eclectic event Cottier has become. Sound House was – deep breath – an old-meets-new reflection on writings and sound experiments by 16th-century philosopher Francis Bacon, performed by the (as it turned out) appropriately named Society of Strange and Ancient Instruments (pictured above).

They brought with them esoteric instruments from Bacon’s time and before, and they took us all through them, too – such exotic specimens as three types of harp, a titchy Renaissance guitar, dulcimer, several species of viol, and the rarely performed lirone, with up to 20 strings bowed in rich harmonies. Oh, and a MacBook Pro, which composer Jon Nicholls used to meld together the live instrumental sounds, recordings of sound experiments the group had undertaken, plus echoes, resonances and more, sending them whizzing round the audience’s heads in a fascinating event that even managed to make you question what a concert could be.

Seated in the centre of the room, with listeners all around them, the quintet of players segued from one piece to another, from crisp Renaissance dance to jagged electronic improvisation, blending into their performance readings from Bacon’s writings and even explanations of the music and instruments we were hearing. It was thoroughly seductive, as informative as it was entertaining (and sometimes simply baffling), and the Society’s performances were eager, enthusiastic and lithe throughout. Best of all, it wore its evident scholarship very lightly – Sound House never felt puffed up its own cleverness, clever though it certainly was. Instead, it was simply captivating, in its own musical and philosophical terms.

The evening ended with one of Cottier’s high-profile visitors: Russian/French violinist Alexandra Soumm, until recently a BBC New Generation Artist, who gave a fascinating if not always convincing recital with pianist Ismaël Margain (both pictured above right). Their opening Mozart Sonata in E minor K304 could have been be Brahms, such was the full-blooded swooping and swaying of their playing, wrung for every last drop of emotion – involving, certainly, but exhausting too (and not really in a good sense).

Their rarely heard Prokofiev Mélodies were far more convincing, fluid and sensuous, with a magical sense of storytelling too. Bartók’s Romanian Dances in Kodály’s version for violin and piano drew some fiery, vicious playing from Soumm, flamboyant and joyful, but she turned Ravel’s Tzigane into a catalogue of fiddle pyrotechnics, focusing on the showy technique rather than musical expression. It took their encore – Heifetz’s gloriously over-the-top reworking of Gershwin’s ‘It Ain’t Necessarily So’ – to bring back the easy-going musicality they’d shown earlier, and it did that magnificently, with Soumm revelling in her rhythmic freedom and Margain pushing himself into the spotlight as a fine jazz improviser.

It might be self-evident to say that the Cottier Chamber Project gets bigger, bolder and, well, better every year – and there may come a point when its three weeks simply get too stuffed with good things for its own good. But under the unflustered, resourceful direction of Andy Saunders, it also shows how a summer classical festival should really be: warm and welcoming, informal, with bags of character, great music-making, and a nice bit of risk-taking thrown in too.

• Cottier Chamber Project continues until Saturday 25 June