Clodagh Simonds could never quite see where she was going when she was making The Salt Garden III, the final part of a trilogy of EPs released by Fovea Hex, the name the Irish singer and composer has worked under for the last decade and a half. In that time, Simonds has produced a sepulchral-sounding body of work that fuses arcane-sounding chorales with brooding electronic underscores that recall everything from Ligetti and Arvo Part through to the nouveau medievalism of Dead Can Dance and the three 1980s albums by 4AD Records supergroup, This Mortal Coil.

This has been the case on the Salt Garden trilogy, as well as Fovea Hex’s first series of EPs, Bloom, Huge and Allure, compiled as Neither Speak Nor Remain Silent. It was the same too on the full-length Here is Where We Used to Sing, released in 2011. Contributors to these have included Brian Eno, Robert Fripp and film composer Carter Burwell, who have worked alongside a core of Colin Potter from Nurse with Wound, violinist Cora Venus Lunny, cellist Kate Ellis, and East Lothian composer Michael Begg. Regular collaborator Laura Sheeran was sadly too busy to take part in the new record.

With a name drawn from the part of the retina that gives the clearest vision, but made blurry by the curse of its second half, it is Simonds, however, who is the heart of Fovea Hex.

“It’s as if I’ve been working in a dark room, and can’t quite see what it is until it gradually becomes clearer,” Simonds says about making the four pieces on the Salt Garden III, released in a limited 10in vinyl edition on former Porcupine Tree driving force Steven Wilson’s Headphone Dust label. “It’s been instinctive and intuitive rather than planned. When I’m writing lyrics I haven’t a clue what it’s going to be about until the words appear, and gradually a picture emerges.”

This could arguably be said too of Fovea Hex as an entity, with Simonds initially approaching Andrew M McKenzie, aka The Hafler Trio before being put in touch with Potter. Simonds first heard Begg on MySpace, while she knew Ellis, Lunny and Sheeran from Ireland’s music scenes.

“The outside input was very much needed,” says Simonds. “I knew the kind of sounds I was after, but I had no idea how to get them, and no idea about virtual and digital technology. In retrospect, it was quite unusual then to combine real strings and voices with electronic music that isn’t dance music.”

As with most things around Simonds, the name of Fovea Hex came about by accident. “It just kind of appeared, and I thought it was a nice phrase,” she says. “It resounded with the idea of not being able to see clearly, and that always interested me since I was very small, this idea that we don’t always get it, and how we can feel strange about how we perceive things. There was something there about not seeing that I liked. On a purely practical level, my name gets misspelt and mispronounced so much that I felt I had to have something. If I’d been called Mary Smith, I might have stuck with that and not bothered.”

Simonds’ musical journey to Fovea Hex has been a remarkable one. She formed her first band, Mellow Candle, aged 11, and had her first record out by the time she was 15. A Mellow Candle album, Swaddling Songs, featured work later covered by All About Eve and Stephen Malkmus. Simonds played keyboards, harpsichord and mellotron on Thin Lizzy’s second album, Shades of a Blue Orphanage, released in 1972, and sang backing vocals on Mike Oldfield’s follow up to Tubular Bells, Hergest Ridge, as well as on Oldfield’s subsequent album, Ommadawn. Simonds would collaborate with Oldfield again in 1990, singing on his Amarok album.

Inbetween, Simonds had stints in New York and London, playing a residency in CBGBs with a band called The Same and composing music for La MaMa experimental theatre company. She also worked for Virgin Records on both sides of the Atlantic before eventually moving back to Ireland in the 1990s. By that time, Simonds was ready to concentrate on music full time again.

“I wouldn’t say I ever stopped music,” she says, “but I got stuck in day job hell for years and years. Then I had a bit of a health scare, which was a wake-up call. Moving back to Ireland, I was so happy to be able to decide what I was doing that day. I was broke, but I was writing again, and I was given a piano that appeared like a miracle.”

A mini-album, Six Elementary Songs, was released under Simonds’ own name in 1996, beginning the slow-burning evolution of Fovea Hex that has led to The Salt Garden. Beyond this, Simonds isn’t sure what she’ll do next.

“It was a long labour, making the record,” she says, “and it feels like I’m just able to draw breath again. I’ll probably not work on anything new again for a while, but having said that, I know that as soon as I sit down in the studio and open up that folder of ideas, which I haven’t done now for about a year, it will be a case of, yes, let’s do that.”

The Salt Garden III by Fovea Hex is available now on Headphone Dust Records.