A sign of growing self-confidence in any young arts festival is having the courage to really push the envelope on a milestone birthday.

The East Neuk Festival's ambitious new project - a once-in-a-lifetime outdoor concert of 32 massed horns in F and B Flat performing the world premiere of a specially commissioned piece from John Luther Adams, the renowned American "eco-composer" and champion of the natural world - certainly ticks the 10th birthday "we're on the map" box.

Not only is Across The Distance to be led by the Scottish Chamber Orchestra's principal horn player Alec Frank-Gemmill plus seven other top professional players from the SCO and around the UK, most of the others will be amateur volunteers from age 11 upwards, crowd-sourced via social media. Such an ambitious musical undertaking has never been attempted before in Scotland.

Preliminary auditions took place at the Glasgow Royal Concert Hall in April, with a run-through in May; the first full rehearsal scheduled was scheduled for yesterday and the dress rehearsal will happen next Saturday evening. The concert, on July 5 at the Cambo Estate, is already sold out - a sign, surely, of trust in director Svend Brown's artistic vision on the part of the concert-going public, buoyed no doubt by the success of Luther Adams's 2013 festival debut, Inuksuit, an outdoor piece for 30 percussionists. According to Brown, people who attended still talk about that day as a "magical memory".

John Luther Adams, who lives in Alaska and New Mexico, is renowned for his large-scale works inspired by the environment and written for outdoor performance, embracing the calls and sounds of wildlife and nature. He's been described as "one of the most original musical thinkers of the new century" by The New Yorker, and he recently won the Best Contemporary Classical Composition award at the Grammys for his work, Beyond Ocean. Adams himself says he strives in his work to create musical counterparts to the natural world around him: "If we're listening deeply, if we're listening carefully with our broadest awareness, both noise and silence lead us to the same understanding, which is that the whole world is music."

This led the composer to examine the concept of 'sonic geography', early examples of which include two works written in rural Georgia: Songbirdsongs (1974-80), which constructs miniature pieces for piccolos and percussion from Adams's translations of bird songs, and Night Peace (1977), a vocal work that aims to reflect the night-time soundscape of the Okefenokee Swamp.

When the 75-minute Across The Distance, written in eight different parts all in harmonics (open notes), is performed as the East Neuk Festival's finale in and around the gardens of Cambo Estate near St Andrews, the audience can expect to be initially surrounded by the players, who then move further and further away so that the sound, variously described as "haunting" and "primeval", gradually fades into the environment. Svend Brown hopes it will deliver a "profound, life-changing" experience, and even dares to hope it might compare with the dream-line Nocturne of Mendelssohn's A Midsummer Night's Dream.

"I anticipate we're going to see a really enchanting work in the sense it's going to return the horn to its original links with hunting and the landscape," he says. "The horn has always been used to communicate from great distances, and the great poetic thing with Across The Distance will be to hear the horn from 100 metres away and for it to be answered by another 200 metres away. To be in beautiful farmland among the trees and birds, with 32 horns all around you, has something very poetic and romantic about it.

"I'd like to see children dance on the lawn and others having a meditative, concentrated experience. Nobody has to clap or respond. I hope to offer a genuinely open and free experience for all kinds of people, one that they will enjoy on their own terms."

The open air having precisely zero acoustic is a bonus rather than a challenge, since the horn was originally an outside instrument. "The mix of natural and man-made sounds really will make the hair on the back of your neck stand up," Brown promises.

Site-specific community engagement may be the buzzphrase of the modern arts scene, but it is not new: Brown reminds us that Benjamin Britten's Aldeburgh Festival set out to do the same thing in the 1950s. Nevertheless, he admits it was a "seriously ambitious" challenge to get the prize-winning composer to commit to creating a brand new piece, and in the process focus the attention of the global music scene on Fife. Indeed, Luther Adams's orchestral work Become Ocean, part of Inuksuit, was awarded the 2014 Pullitzer Prize for Music. His most recent work, Sila: The Breath Of The World, represents the air element, following the representation of water in Become Ocean and the earth element in Inuksuit.

Garnering such a high concentration of horn players is a pretty nifty achievement, too. Qualifications required from those volunteering to be auditioned were only that they must be at least Grade 5, but there was no age restriction. Brown says that Margaret Douglass of the Fife Horn Union, who teaches primary school-aged children, was a significant factor in his decision to try it. "Margaret and her Fife horn players are the reason we're here," he said. "Legacy is a big part of this project and we'd like it to encourage people young and old to keep on playing after it's finished."

For his part, Alec Frank-Gemmill is intrigued by the project because he's never played with 31 other horns before, and certainly not at so many different ages and levels of proficiency. "Strauss's An Alpine Symphony is supposed to have 12 off-stage and eight on-stage horns 'or as many as you can find', but it never actually happens," he says. "So for this I feel a mix of excitement and terror.

"Usually you associate horn music with classical music, but this piece takes the horn back to basics and treats it like a hunting horn. The sound that comes out is strange and has a haunting quality. The sonority takes you back in time, but at the same time it's contemporary. The piece is designed for amateurs and professionals, and hopefully there's something that everyone can do. It's inspiring for amateurs to play alongside professionals, and get that sense of camaraderie."

What music might Adams make for the distances of a country estate in rural Fife? That remains to be seen and heard. Meanwhile, volunteer horn player James Holloway, formerly director of the Scottish National Portrait Gallery and currently gearing up for his playing role in the project, sounds the final note: "My fellow volunteer and playing partner, a retired haemotologist, turned to me at the run-through and said, 'it doesn't get much better than this, does it?'. And I can only agree."

The world premiere of Across The Distance by John Luther Adams, performed by massed horns for the finale of the East Neuk Festival, takes place at Cambo Estate, Fife, on July 5 2015. For this and full programme details, see www.eastneukfestival.com