Rock 'n' roll uproar and monastic ambience rarely make for exultant bedfellows.

But the twain are set to harmonise at Paisley Abbey on October 14, when the former monastery hosts unique recitals from alt-rock diabolists The Twilight Sad and chamber-pop charmers Admiral Fallow, both of whom will perform with the Royal Scottish National Orchestra.

Taking place as part of Active Events' Paisley arts festival The Spree, and curated by BBC Radio 1 presenter Ally McCrae, the abbey performance will be arranged and conducted by John Logan.

"The Royal Scottish National Orchestra is delighted to be part of The Spree," says RSNO's Jane Donald. "Our concert provides us with an exciting opportunity to collaborate with two of Scotland's most exciting bands, and partnerships like the one we enjoy with The Spree enable us to take Scotland's national orchestra to new audiences."

Paisley native McCrae will host the performance, which is also supported by Renfrewshire Council, Creative Scotland and EventScotland. "I've always wanted to get an orchestra teamed up with indie bands, just for the spectacle of it," says the broadcaster and guerrilla gig activist, whose ingenious Detour venture has masterminded live shows in curry houses, under bridges and in Glasgow Science Centre's Planetarium.

"Radio 1 had The xx playing with the BBC Philharmonic, and that was just spectacular," McCrae continues. "The Twilight Sad's sound lends itself so well to getting a big string section in – they'll be playing a stripped-down set, which gives the songs even more space – and Admiral Fallow sprung to mind when I saw them play with a string section in London. I've seen them a ton of times, but that was just amazing."

The bands – both of whom were shortlisted for this year's Scottish Album of the Year Award – are equally excited by the forthcoming concert's sense of ceremony. "We're three guys from Kilsyth who like drinking and writing moany songs," laughs The Twilight Sad's James Graham. "The last thing we thought we'd ever get to do is play with an orchestra in a place like Paisley Abbey. It's quite a privilege to be honest, for someone to take our music and adapt it in that way," he says. "It's a wee bit daunting, but it's also amazing, and I realise that not everybody gets to do this, so we're really going to throw ourselves at it."

The Twilight Sad recently performed a few songs with the Cairn String Quartet in the decorative auditorium of Glasgow's Oran Mor, and Graham acknowledges buildings can perform a starring role in a live show. "It's not that we don't respect dingy venues, but I do seem to have a different attitude towards things when I'm in a place that's maybe regal or churchy," he offers.

"I don't know why it is, but you do react to your surroundings – you soak it in, you let things breathe a bit more. When you approach something like this, at Paisley Abbey, there's a different mentality."

Admiral Fallow count several classically trained musicians among their number, and their regular rock cache includes clarinet, flute and double bass, but in terms of scale and ambition, the Paisley Abbey show will be unprecedented, says frontman Louis Abbott.

"The space probably isn't going to lend itself to doing a regular full band thing with additional orchestra, so we're going to rip it all apart and put it back together utilising as many of the orchestra players as possible," he explains.

"We've not decided what songs we're doing, but I think we'll try and be really flexible. It's a way of keeping our existing songs fresh, but also of taking that further – of completely changing them musically; of starting from scratch. I'm also really interested in hearing the arrangements of The Twilight Sad songs – I think that'll be something fairly cathartic."

If the concert looks set to shed new light on the RSNO, The Twilight Sad and Admiral Fallow, then so too does it raise the possibility of their orchestral-rock arrangements being transcribed to sheet music – something neither band has had in the past, and a prospect that enthuses both acts. "We'd love to think that when these parts are put together they're not just chucked in the bin after this one gig," says Abbott. "I don't know what the copyright aspect would involve, but the thought it could maybe be available as a score is really exciting. It'd be totally thrilling if a bunch of schoolkids were to take something like this on, or do something else with it."

The Spree arts festival (October 10-20) coincides with the Mod (October 11-19), Scotland's celebration of Gaelic language and culture, which takes place in Paisley for the first time. To mark the occasion, McCrae will present part of the Paisley Abbey gig in Gaelic.

"I don't know a word of Gaelic," he laughs, "but things like this show what a rich heritage we have in Scotland."

The concert has a personal resonance for McCrae, whose brother Ross is a composer, and whose late father Gordon was a ceilidh musician and local historian. "My dad used to work on archaeological digs around Paisley Abbey, so I know it really well, it's such a haunting building," he says. "I used to go to classical concerts when I was a kid, and I worked for Celtic Connections which is where I met Lisa [Whytock of Active Events], and then there's the more rock 'n' roll Radio 1 side of it. This merges all those things together," notes McCrae. "It'll be amazing."

The RSNO with The Twilight Sad and Admiral Fallow: Paisley Abbey, October 14. The first 100 tickets will be on sale tomorrow (Saturday) via Ticketmaster (08444 999 990), priced £22 plus booking fee. The remaining tickets will be available from July 15 via www.thespree.co.uk