Reading the odd review of BBC’s Electric Proms the other week, and the default concept of chucking in orchestra/choir to create an “event”, I started wondering whether the pairing of Grizzly Bear with the London Symphony Orchestra was such a good idea. After all, the songs on “Veckatimest”, even the ones with strings, are so airy and lacking in bombast. Sometimes, I find myself barely noticing the instrumentation, with the focus so intently on those ornate vocal melodies.

Reading the odd review of BBC’s Electric Proms the other week, and the default concept of chucking in orchestra/choir to create an “event”, I started wondering whether the pairing of Grizzly Bear with the London Symphony Orchestra was such a good idea. After all, the songs on “Veckatimest”, even the ones with strings, are so airy and lacking in bombast. Sometimes, I find myself barely noticing the instrumentation, with the focus so intently on those ornate vocal melodies.

Remarkably, Saturday’s show at the Barbican manages to pull off a similar trick; thanks, I guess, to the superb harmony singing of the four Grizzly Bear members and the orchestrations of Nico Muhly, tucked away in the corner of a very crowded stage behind a grand piano. I’m struggling to think of a band+orchestra show where the orchestra has been used in such a subtle way. In fact, Muhly’s arrangements are sometimes so discreet, it seems an even more decadent event.

From “Easier” on, as Chris Taylor crouches on the floor with a flute, Daniel Rossen takes the lead and Edward Droste lets out his first levitating sigh of the evening, Muhly’s deft and intricate arrangements are bewitching rather than intrusive. The spaciousness remains, for the most part, with the band, artfully, playing a long game. The build-up to crescendos lasts over several songs rather than the odd minute or so, which makes the fireworks – the quixotic swell of “Southern Point”; a bit of feisty atonalism at the end of “Fine For Now”; the opulent menace of The Crystals’ “He Hit Me (And It Felt Like A Kiss)” – all the more impressive. Only on the grand romance of “I Live With You”, perhaps, does it feel as if the orchestra are roaring at full strength; coming as this does a good hour, 75 minutes, into the show, the impact is huge.

Unlike many of these kind of events, then, where the core band get somewhat drowned out, their individual talents really shine here, and not just the twin frontmen, Droste and Rossen. It’s Chris Taylor, for instance, who provides the Frankie Valli falsetto on the ethereal doo-wop of “Knife”, in between multi-tasking on bass, flute, sax and shortwave radio. And it’s the bow-tied drummer, Chris Bear, dwarfing his compact kit, who turns out to be the evening’s musical scene-stealer, giving everything a roll, snap and swish that’s much jazzier than the records sometimes suggest.

Bear is in his element on “Two Weeks”, one of two songs (the other being the other hit from “Veckatimest”, “While You Wait For The Others” – sung by Rossen rather than Michael McDonald, unfortunately) played by Grizzly Bear accompanied only by Muhly and the LSO’s harpist.

The fact that these two receive more or less the biggest receptions of the night is probably due to familiarity more than the more parsimonious arrangements. But in a way, as conductor Jim Holmes leans on his podium centre-stage and looks on approvingly, they only heighten the extravagance of the evening. What audacious proflicacy, to hire all those musicians, and use them, relatively, so sparingly.