Pints of Guinness ease the nerves inside the Air Products Social Club, a Phoenix Nights throwback with wooden tables, pink velour chairs and packets of Big D peanuts. The Fron Male Voice Choir have assembled to hear their new album, Voices of the Valley: Encore. Second albums are notoriously difficult – though not, generally, because of whistling hearing aids and clattering loose dentures. But platinum-selling artists don’t come any odder than this choir from Froncysyllte in the North Wales valleys.

Signed by Universal Classics and Jazz – the biggest name in classical crossover records – the Fron’s debut outsold every classical album last year, shifting 100,000 copies in three days. It beat Scissor Sisters in the pop charts. Fron life has taken a surreal turn ever since: the choristers shared the Classical Brit Awards bill with lute-loving Sting; Hollywood has optioned the film rights to their story; their Women’s Institute-esque, naked charity calendar is on the shelves in time for Christmas. “It’s gone a bit crackers,” suggests Allan Smith, the Fron’s twinkly-eyed treasurer.

Smith has sung first tenor with the Fron for 22 years. “Gentle is the world that sings, blessed are its songs,” reads the motto on his official choir tie. The profit-driven music business does not seem a natural bedfellow for these good-natured singers. “There could have been a clash,” agrees Smith. “But when negotiations began we told Universal: ‘We will allow nothing to endanger the image of the Fron and our charity status because that’s what we’ve done for 59 years’.”

Daniel Glatman, the Universal manager, remembers Smith’s reaction on being offered the deal: “ ‘Oh yes,’ he said, ‘it’ll attract new members. I’ll put it to the committee’.” Glatman has a solid-gold pop reputation – he managed the boy-band Blue – but he is refreshed by his new charges. He calls the boys his “bunch of amateur Welshies”, signing the choir after hearing them sing at a friend’s wedding. “I knew it could be big,” he begins. “Everybody loves Welsh choirs, but no one had the opportunity to buy one before.” Glatman saw gold in the human connection, the “that could be my grandpa” element. “People buy into the music and they buy into them – they’re real, normal, unaffected.” A year on, this remains true.

For every glitzy appearance in front of 80,000 at Cardiff’s Millennium Stadium there’s a charity gig for the Welsh Caravan Club in a cattle-shed in Corwen (where the choir’s dress jackets somehow fell into the cowpats). Stretch limos aren’t in evidence; money from the record deal is strictly reserved for the choir’s coffers, and many of the choristers work full-time, as stonemasons, farmers and policemen.

Like a hundred other choirs or cricket clubs around the country, supporting the men are the dependable wives and girlfriends, as unWAGish as you can get. “If they’re going on the coach to London for a concert, you like to see they’ve got enough sandwiches,” says Gill Jones, member of the Ladies’ Committee. “The choir doesn’t need our money now but we still meet because when the bubble bursts we’ll need to fundraise again.” Refreshingly against type, Universal has left the Fron image well alone. The official choir website remains a village-hall affair with pictures of the cake baked to celebrate their recording and mugshots of all 70 members, aged from 17 to 86 years.

Among them is Dennis Williams, boisterous linchpin of the choir and founding member back in 1947. “Singing was everywhere then,” remarks the 76-year-old. “In the chapel, in the school . . . Now people are joining later, in their fifties or in their retirement.” You still find the third generation of a single family in the choir and personal stories stretch through its history.

“My dad was in the choir,” remembers Dave Jones, the chairman and a prison warder, who has sung with the Fron for 12 years. “We had many an argument about joining; it wasn’t cool, was it? One day I crept along to a rehearsal. The hairs on the back of my neck stood up. To my shame, I never told my dad.”

Back at the social club, a hush descends, broken by the first bars of Yesterday, followed by Elvis’s Can’t Help Falling in Love. The Fron’s repertoire has changed somewhat as Glatman and Universal have inevitably steered their stars towards “the uncomplicated, the familiar”. How do the oldies feel about this?

“We’ve never sung only traditional Welsh music; we were always international in what we sang,” Williams says. Few of the choristers read music, but they tackle everything, from church music to Baroque fare, in 16 languages. “We like the serious stuff, but The Rhythm of Life and You’ll Never Walk Alone– you’ve got to put light stuff in concerts.”

What rankles more than the creeping pop is the lack of time to take part in competitions. The Fron was formed to compete and is among a handful of choirs to have won the prestigious Llangollen International Musical Eisteddfod three times. “We have a competitive backbone,” says Allan Smith, “and some of us will be determined to revert to that as soon as possible.”

Ann Atkinson, a mezzo-soprano who has sung at Glyndebourne, is the choir’s musical director and conductor. “A competing choir has got some grain to it,” she says. But the technical demands of competition require up to six months’ rehearsal – time now given over to promotions and concerts.

I’d heard that the Fron likes “a good afterglow” – booze-up after a concert – and the playback party is soon in full swing. Anecdotes flow with the drinks and the choristers cheer along to their album. The Welsh favourite We’ll Keep a Welcomestrikes up and eyes grow misty around the room.

Wiktor Jurkojc, a second bass, takes my arm: “Don’t we make a great sound?” he asks. “There’s power in it.” And pride, too; a pride that one suspects will outlast any recording deal.

Voices from the Valleys

Rhos Male Voice Choir
Katherine Jenkins has sung with the former BBC Choir of the Year on its tour.

Cor Godre’r Aran
Aka the Aran Mountain Choir. Twice winners of the International Llangollen Eisteddfod.

Flint Male Voice Choir
The 30-strong band like a bit of Queen’s Bohemian Rhapsody mixed into their Welsh favourites.

Cor Meibion Caernarfon
Local boy Bryn Terfel is the choir’s sponsor. The 60 choristers are touring the UK and recording a new album.

Pontarddulais
The self-styled “most successful competitive male voice choir” have won the Royal National Eisteddfod a record 14 times.

Voices of the Valley: Encore is released on UCJ on November 12, www.fronchoir.com

Explore Music

• CD Reviews

• Live Reviews

• Classical

Editor's choice

• The 100 Best Films of the Decade
• 70 facts you didn't know about Marvel
• The 50 Biggest Movies Of 2010