One of the most haunting moments of Shirley Collins' 'America Over The Water' talk at London's Purcell Rooms last year was the singer and folk historian's memories of Sacred Harp choirs in the white Protestant churches of the American South in the Fifties. As she described the congregation's voices pulling together the hymns of generations, a recording filled the hall: robust, stretched and austere. The familiar Christian songs, so anodyne to any of us brought up in church schools and choirs, were thrown open to heavier ritual associations, by the wide, weird intervals – closer to plainchant or power chords – and the drifting, idiosyncratic phrasing of massed, inexpert singers.

Sacred Harp, or shape note singing, implies both democracy (in its notational method, devised in the 19th Century to be accessible to non-music readers) and control (in its austerity, and its use in the strictest Christian communities), a combination that exerts a musical pull beyond ontological concerns. When its style is woven into traditional, non-religious music, as it is on Anglo-American duo Cath and Phil Tyler's first album on Newcastlebased experimental label No-Fi, you’re reminded both of the folk roots of most hymn tunes and of the devotional associations our ears make with modal music, from Indian ragas to metal.

And you're reminded of much more: Dumb Supper is one of those rare modern folk albums that will find a home both in the longstanding 'traditional' music community and among those attracted to the form's more experimental and lo-fi possibilities. Cath Tyler's vocal style harks back to those backwoods churches, but away from the choir, there's as much in it of Thalia Zedek or Michael Gira: that sense of buffeted, fateful reserve. Similarly, co-vocalist Phil Tyler's muscular guitar and banjo playing shies away from displays of fancy fingerwork, preferring a sparse, purposeful roll and groove or, as on the likes of 'Death Of Queen Jane' and 'Stirrup', sombre phrasing that follows the vocal line with pauses that reverberate with rue and wonder.

When the duo pick up speed, on 'Devil's Song', 'Fisherman's Girl' and 'Farewell My Friends', there's still not a note wasted; instead, the onus is on rhythm, momentum and force. The latter song owes some of its urgency to an underlying D-drone more likely to be heard in, say, Six Organs Of Admittance, and 'Morning' makes use of a distorted electric riff – but Dumb Supper is not a folk-rock or psych-folk album. It uses none of the devices practitioners of those genres often crack out to convey oddity, timelessness and so on, and thus conveys those things all the more.

It's a weird looking-glass effect many folk fans will be familiar with: the simpler you play it, the stranger it gets, and there’s a musical, emotional distance that must be achieved the deeper you want to get, like a kind of run-up to the heart. Shirley Collins always understood this, and so do Cath and Phil Tyler. Dumb Supper eschews drama, faces up to death; bypasses romance, goes straight to love.

What attracts you to a particular traditional song?
"Sometimes it's an appreciated story, sometimes a really good tune. Sometimes neither, but a singer or player is so vibrant that you can’t help being moved or trying it out. A combination of all three things really packs a wallop."

When playing traditional music, what's the process of adaption and arrangement like?
"It's generally a slow and unhurried process, with occasional quick inspiration. Once there’s something we like, it generally keeps the same shape, though variations might creep in. As we sing or play something more, we lock in with each other more, which tends to bring out something new again."

Why do you think people are still so drawn to folk music?
"Its accessibility and simplicity, and straighforwardness. You don't need to know anything to 'get i'’. For song with stories, the narrative draws you in. Many times listening to non-folk music, I’ve heard songs that sound fine, but I end up with no idea what they were about. In traditional music, even when a story is old, it's got stuff in it that still is important: love, sex, death, beliefs, fear, joy, hunger, life all still mean something now."