Mairéad Ní Mhaonaigh has known for quite a while that she’s onto a good thing.

The co-founder, lead vocalist, and fiddler for the acclaimed Donegal band Altan, Ní Mhaonaigh began playing traditional music as a kid and has scarcely stopped since then. 

“The music never leaves you; it just becomes better,” she says. “The more you work at it, the more you realize how little you know. There’s so much to learn, but there’s never enough time! I find most nights now, in the winter, if I’m at home I end up playing my fiddle until all hours. I mean, the music just doesn’t stop. It becomes part of your DNA. It becomes like eating and drinking and breathing – you have to do it.”

Boston-area Irish music fans will have an opportunity to indulge their enjoyment of Ní Mhaonaigh and her fellow Altans when the band plays at Somerville’s Crystal Ballroom on March 24 (at 4 and 8 p.m.). 

Closing in on the four-decade mark, Altan comes to town in the wake of two important developments: the addition of fiddler-violist-vocalist Clare Friel as a full-time member and the release of the band’s latest album, “Donegal.”

Friel, who plays in a trio with her sisters Anna and Sheila, grew up in Glasgow but has strong family connections to Donegal, where she spent a significant amount of her childhood. Among the sisters’ foundational experiences was attending the renowned Frankie Kennedy Winter Music School – originally named for Ní Mhaonaigh’s late husband, with whom she founded Altan, it’s now known as the Winter School – where they crossed paths with many prominent musicians in the Irish traditional scene, including Ní Mhaonaigh. In fact, after their first visit there, the sisters – then in their early teens – were subsequently invited to perform with Altan at the Celtic Connections festival in Glasgow. 

In 2018, Friel became part of the SíFiddlers, an ensemble of Donegal female fiddlers whose members also included Ní Mhaonaigh. Four years later, she joined Altan as a guest musician for its fall 2022 and spring 2023 tours, becoming an official full-timer last summer; the other members are guitarists Dáithí Sproule and Mark Kelly, accordionist Martin Tourish and Ciarán Curran on bouzouki and mandolin.

Friel’s presence has restored the twin fiddle dynamic Altan had for many years, until the departure of long-time member Ciarán Tourish in 2017, while adding another female voice to the group’s already impressive vocal assets. She also represents a turn of the circle, as part of a generation now come of age that grew up listening to, and learning from, the likes of Altan. 

 “We’d been inviting people to join us as ‘special guests’ on tour, just to give some variety to the audience,” says Ní Mhaonaigh. “But we realized after Clare started playing with us that she was one of these people you really couldn’t do without. She comes from the Donegal fiddle tradition, same as me, but she’s really marked her own way with it, and is very well respected for what she does. And she’s an absolutely beautiful singer as well. We haven’t even really seen her full potential in the band yet, so we’re all excited about what lies ahead.” 

While the band actually began work on “Donegal” during the pandemic, before Friel’s arrival, her involvement made the album all the more meaningful as a back-to-the-roots project. Their last album, 2018’s “The Gap of Dreams,” emphasized recently composed material, including tunes written by Ní Mhaonaigh’s daughter Nia Byrne and Kelly’s son Sam, both of whom made guest appearances, and also had an underlying theme of the indispensability of music, songs, and dance to past generations coping with the demands of rural life as well as famine, conflict and emigration. Their 2015 release, “The Widening Gyre,” explored Irish-Americana fusion with guest stars like Alison Brown, Jerry Douglas, Tim O’Brien, Mary Chapin Carpenter, and Boston’s own Darol Anger.

“Donegal,” quite simply, is about Donegal. It’s not just that most of the tunes and songs (both traditional and contemporarily composed) originate from, and/or reference Donegal, such as the splendidly vibrant “Donegal Selection” track that includes a reel associated with the late Tommy Peoples, or the Gaelic songs like “Liostáil mé le Sáirsint” and “Faoiseamh a Gheobhadsa” (on which Friel takes the lead). It’s that the band endows them with an essence of Donegal, if you will – the mystique and mystery often associated with the place. 

Consider, for example, the one English-language song on the album, “The Barley and the Rye,” a comic, rather saucy ballad which is associated with a number of British singers, notably Harry Cox – from whom it was collected in 1927 – as well as Martin Carthy and Peter Bellamy. Ní Mhaonaigh renders it gently but with attentiveness for the intrigue alluded to in the narrative, to a cool-jazz-like backing by Kelly, Sproule and Curran.

The instrumentals are solid as ever, and there’s no overlooking Tourish’s accordion or Curran’s dexterity – especially on the slow reel “Yellow Tinker” – and the accompaniment by Kelly and Sproule. [A fuller review of “Donegal” will come at a later date.]

Ní Mhaonaigh, for her part, feels energized by having Friel’s fiddle as part of the band. “The twin fiddles are an important part of Donegal music. You have them playing in unison, and then one will go to the octave, and it really just widens the sound. Having that back in the band is wonderful.” 

The album was “boiling in our heads for a long time,” says Ní Mhaonaigh, but in retrospect the pandemic-related delay in finishing it was largely for the good. “We had the luxury of time to decide what we wanted to do, and we could take everything apart and put it back together. So, we were playing around with a lot of harmonies and polyrhythms. That, to me, makes music interesting. 

“The songs that I chose are ones I’d been thinking about recording for a long time. A lot of the tunes have a good fiery sound to them. They wouldn’t be perfection, but sometimes perfection is too easy – you can cut and paste and all that. We wanted to go for that rawness, like what you might hear on a live album.” 

Above all, she says, the band wanted the album to underscore the distinctiveness of Donegal, and not just its music. “Donegal is a bit different than the rest of Ireland. The fiddle tradition has a lot of unusual tunes, ones you wouldn’t necessarily find in other parts of Ireland, and of course, there are the Scottish elements – the strathspeys or ‘highlands’ as they’re called. And we have our own accent, which has remained intact.

“It all goes back to that great Gaelic kingdom of Ireland and Scotland; we all had the same language. That fell apart after the Battle of Culloden, when the Jacobites were defeated. And then there were all the evictions, and the British misrule of Ireland, trying to get rid of anything having to do with Gaelic society, especially the language. But that never happened. The legacy is still alive, in Donegal and Scotland, and a lot of young people are tremendously interested in exploring it. There is such a huge, deep tradition of words, and out of that comes the music with all its intricacy.”

Sometimes the music is practically right under one’s nose, says Ní Mhaonaigh: She notes that her bandmate Tourish came into possession of a manuscript containing some 400 tunes – attributed to named musicians between 1890–1910 in the Taughboyne (House of Baoithín) parish of Donegal – that was discovered in the house of a relative who had died. Tourish wound up including three reels from the manuscript, along with a fourth he composed, in “The House of Baoithín Selection” on the new album.

Ní Mhaonaigh herself was the beneficiary of similar good fortune, making the acquaintance of a young fiddler, Mícheál Cherry, while teaching at a fiddle school; he taught her a couple of obscure reels that he had collected himself, which Ní Mhaonaigh used as part of the “Donegal Selection” track.

“Many of us thought that, with more traditional music being available on records or tapes or CDs or what have you, that everyone would mangle their traditions together. But it’s gone the opposite way. Instead of blending everything, there’s more of a focus on a specific style. I praise the young people, like Clare and Mícheál, for that – they’re very discerning – because that means the music retains its very special character.”

For more about Altan and “Donegal,” see altan.ie; The Crystal Ballroom website is crystalballroomboston.com