Here is a thrill that never gets old:

finishing a concert in the Norse-medieval vaults of St Magnus Cathedral then emerging into the musky, silvery gloaming of an Orcadian midsummer night.

There is no overstating the potent sense of place that underpins the St Magnus Festival. Sure, the festival's programme is enticing enough - this year featured memorable performances from the Trondheim Soloists, BBC Singers, BBC Scottish Symphony Orchestra, Fidelio Trio and more.

But roughly half of ticket-buyers are visitors, easily able to access decent concerts much closer to home. What lures them north to these islands are the same factors that first attracted the festival's founder, Sir Peter Maxwell Davies, when he moved here back in the 1970s: the promise of music set against the Orcadian landscapes, soundscapes and light.

The midnight sun famously does things to your energy levels, too: here is a classical music festival whose focal point is the after-hours folk club. Everyone seems to end up there - performers, composers, audience, even (on this particular Saturday night past) the UK's Italian ambassador and Scotland's culture secretary Fiona Hyslop. As festival director Alasdair Nicolson told me, "there's no point in folk coming up here for one or two concerts. If they're going to travel all this way, they might as well get settled in for the full experience."

St Magnus Cathedral is a magnificent place for concerts. Built of glowing red sandstone by Viking earls in the 12th century, the high nave is thick-set and narrow; where many cathedrals swamp a choir with masses of reverb, here the acoustic is warm, clear and immediate.

On Friday night, the BBC Singers under David Hill sounded vibrant and shapely in Palestrina's Magnificat primi toni, soft and lilting in Judith Weir's Vertue. Less successful was a vacuous new piece called Toil & Trouble by the Norwegian composer Cecilie Ore, a succession of pop-quote texts (snippets of Shakespeare) and gimmicky whispered chanting.

At the heart of the Singers' programme was Maxwell-Davies's Westerlings. This is a challenging, virtuosic, visceral work from the 1970s in which piercing high soprano notes are plucked from the air as if shrieking sea birds and Orkney's squalling seas and shifting skies are seared into the fabric of the score. It is restless, evocative music, and was superbly delivered here.

Back at the Cathedral the following night, the Trondheim Soloists - Norway's foremost string ensemble and regular St Magnus visitors - gave a peerless account of Grieg's Holberg Suite. Rugged, robust and brimming with spirit, the first movement was gutsy and radiant, the second poised and unhurried, the fourth - the beautiful Musette - stripped-back to raw, earthy essentials.

Later they were joined by nyckelharpist Emilia Amper. She is something of a star of the Swedish folk instrument thanks to her feisty playing and stage presence to match.

She started her set alone, just her unwavering voice pitting tangy open intervals against the bittersweet nyckelharpa, then later roamed through supercharged polskas and traditional tunes. The Trondheims were relegated to a luxurious backing band; the sound was sumptuous, but you wonder whether it's the best use of these terrific players.

The next day - a soft, grey, slow kind of a Sunday - the Fidelio Trio gave a superb afternoon recital in Stromness Town Hall. The sound of this trio is irresistible: big-boned and muscular, it's driven by pianist Mary Dullea (her forthright attack makes every note sound essential) and coloured by the full-throttle ardency of violinist Darragh Morgan and cellist Robin Michael.

I have never heard such a meaty account of Faure's late Piano Trio in G Minor. The outer movements were dark and blustery, the Andantino beautifully sculpted. In Ravel's A-minor Piano Trio those lines were maybe too-strongly defined - here I missed a sense of flux and skittish play - but the work's ecstatic climax was gorgeously expansive.

Between the two French masterpieces was the First Piano Trio by Alasdair Nicolson. (When he became St Magnus director, Nicolson was told in no uncertain terms by Maxwell Davies that he must retain his composer's hat while running the festival - Max's own precedent, after all.) Subtitled Half Told Tales, the trio is a work of wisps and glimmers, reminiscent of Nicolson's roots as a piper and fiddler from Skye and shot through with Gaelic lullabies. Composed for the Fidelios in 2011, it could hardly have been better played than this perceptive, shimmering performance.

Every year St Magnus hosts a visiting orchestra, this year the turn of the BBC Scottish Symphony Orchestra. Venue is always an issue here. The much-maligned Pickaquoy Centre - a sports-gym-cum-arts-complex on the outskirts of Kirkwall - can hardly claim the ambiance of St Magnus Cathedral or the symphonic acoustics of Glasgow's City Halls. Filled with the full forces of the BBC SSO, the BBC Singers and the amassed St Magnus Festival Chorus, the decibel levels were colossal.

Conducting was the fast-rising young English talent Ben Gernon: he has been making waves as Dudamel's assistant in Los Angeles and his style was instantly likeable in a bright, glossy romp through Vaughan Williams's overture The Wasps.

Jennifer Pike was soloist in Sibelius's Violin Concerto but this was far from her finest night. Her opening lines were forced and frosty, her cadenzas soulless and some ropey patches had Gernon proving his cool-handed command to keep things on the rails.

A blazing performance of Belshazzar's Feast obliterated the disappointment, though. The chorus sounded triumphant (give or take a few scraggly edges) and the orchestra offered unabashed dramatic sweep. The great Russian baritone Sergei Leiferkus was a formidable soloist, too, bellowing thick-accented lines just inches away from the front row.

Late on Monday night, the lights dimmed low in St Magnus Cathedral, violinist Hugo Ticciati played a solo recital that I suspect will be the festival's highlight for many. His concept was risky: a kind of stream-of-consciousness (or his term: "dialogical flow of music") that included fragments of Bach, passages of improvisation and works by Arvo Part, Akira Miyoshi, Nigel Clarke and more.

Ticciati roamed the Cathedral for a continuous hour, eking out resonant spaces and delivering much of the recital from behind the audience. The scope for incongruity or indulgence was considerable, but this turned out to be a mesmerising and deeply moving experience.

His technical and musical command are extraordinary and his creative imagination is compelling. After the concert, Nicolson hinted Orkney might be hearing a good deal more from the violinist in years to come.

Kate Molleson travelled to Orkney with Northlink Ferries