There’s nothing in the Musician’s Universal Handbook that says you have to be friends with your bandmates: creative differences, artistic temperament, hours of rehearsal, schlepping to and from gigs – all that can be pretty demanding on a relationship. But the fiddle-and-harp duo of Brighton residents Jenna Moynihan and Mairi Chaimbeul doesn’t have many problems on that score, the two sharing not only an address but also a fondness for long train rides and, according to Moynihan, “1990s dance parties,” among quite a few other things.

More to the point, Moynihan and Chaimbeul share a love for Celtic music, specifically that of Scotland, flavored with Appalachian and other influences, traditional and otherwise. Having emerged as one of the Boston folk scene’s most visionary collaborations of recent years, they have now released their first full-length album, “One Two.”

The Moynihan-Chaimbeul story is in some ways a by-now familiar one in the Boston-area Celtic music annals: Two people from distant locales – Moynihan from New York’s Southern Tier, Chaimbeul from Scotland’s Isle of Skye – pursuing different musical interests connect through the Berklee College of Music, with glorious results.

“The more time we’ve spent together, the greater a musical intimacy we’ve developed,” says Moynihan. “A great part of that is our friendship – it’s rare you can share so many levels of connection. We hardly ever butt heads about what should happen, because we have a similar vision – the whole being greater than the sum of its parts.”

Chaimbeul agrees. “There’s an instinctive quality to our music. We seem to know what the other is going to do. It’s kind of like lying on a giant marshmallow – you just feel very supported and comfortable.”

Moynihan and Chaimbeul’s sound is not of the pin-your-ears-back, knock-you-into-the-next-room variety of Celtic music. It insinuates itself into you, gathering strength until you’re suddenly conscious of how full-bodied and intense it is. “Dialogue” is an oft-employed metaphor to describe the interplay in a musical duo; with Moynihan and Chaimbeul, it’s more like a conversation with multiple dialects.

Moynihan will take the melody and explore it, tacking on variations in fingering and bowing that might be Scottish, or Appalachian, or of some other source. Chaimbeul will establish a steady pulse underneath the fiddle, and then venture out on a more elaborate course, perhaps doubling up on the melody or transitioning into some ambitious improvisations. Or it might be Moynihan softly plucking or bowing a riff, and Chaimbeul taking the lead, the resonance of the harp strings meshing with the dulcet tones of the fiddle – as is the case at the outset of “Kyle Tune,” their joint composition that opens “One Two.”

Other delights on “One Two” include the traditional “Nighean Donn Nan Gobhar,” which puts into sharp relief the respective qualities of harp and fiddle, each expressing its own nuances within the tune; the lament “Mo Run Geal Og (My Fair Young Love),” heartbreaking without being maudlin – Chaimbeul adds a subtle, elegiac harmonium drone at the outset; the up-tempo briskness of the pipe tune “Malcolm Johnston” and “Steaph’s Red Shoes,” a Chaimbeul original (listen to her use of bass strings to ratchet up the tension with Moynihan’s melody line); and, taking their repertoire farther afield, tunes from Brittany and Sweden, the latter (“Norsken”) with an extensive range Moynihan absolutely nails.

“One Two” builds on the duo’s 2014 CD/EP, “Back and Forth,” recorded early on in their partnership (it’s now living “in a small corner of the Internet,” Moynihan quips), as well as Moynihan’s 2015 solo album, “Woven,” on which Chaimbeul appears. As Moynihan explains, “We did ‘Back and Forth’ in several hours – our feeling was ‘Let’s just record.’ So it was a total snapshot.”

Says Chaimbeul, “‘One Two’ is also a snapshot, but it has a different feel to it, because we’ve had more time together to get settled. We’re more connected musically and so we were able to dig more deeply into what our sound as a duo is.”

Moynihan and Chaimbeul followed different musical paths to Berklee. Moynihan started out with Suzuki lessons as a schoolchild, but her teacher had a fondness for Celtic music and nudged Moynihan into exploring it. Moynihan was drawn to the cross-genre playing of American fiddler Jeremy Kittel, which led her to other innovative fiddlers like Alasdair Fraser, Hanneke Cassel, and Berklee faculty member Matt Glaser. Deciding against the classical-conservatory route, she came to Berklee, where she studied performance with a minor in American roots music.

Chaimbeul had plenty of exposure to and instruction in traditional music as a child, yet she never saw herself tied to it. She took up harp at age 8 – she doesn’t remember exactly how she arrived at the choice – and at age 12 went to school in Edinburgh. While most of her music education there was classical, she had the opportunity to work with harpist Catriona McKay, whose multiple-influence style she found intriguing – much as Moynihan had been struck by Kittel’s music. Chaimbeul also was drawn to the jazz music community in Edinburgh, and decided she wanted to study harp in a jazz context. Berklee, she felt, would be the place to do that.

Paradoxically, coming to Boston awakened Chaimbeul’s interest in traditional music, especially the largely unfamiliar bluegrass and old-timey she heard at Berklee and around town. And at Berklee, it’s not especially difficult to find people who share similar interests and ambitions.

“We were certainly aware of each other – I would hear about ‘that Scottish girl who plays harp,’” recalls Moynihan, who was in her senior year when Chaimbeul arrived. Larry Bethune, then Berklee’s vice president of student affairs, suggested the two of them should get together and play. “Our first meeting was a rehearsal, our second was a gig,” says Moynihan. “And our second gig was at the British Consulate.”

Since then, they’ve performed locally at The Burren, Club Passim, BCMFest and “A St. Patrick’s Day Celtic Sojourn,” as well as the Acadia Traditional School in Maine, the Edinburgh International Harp Festival, and Folklub in Glasgow.

Yet Moynihan and Chaimbeul also have had to spend time apart pursuing other collaborations: Moynihan with folk-roots-pop string band Laura Cortese & The Dance Cards, for one, Chaimbeul with the “prog-trad” outfit The Aerialists. In fact, they spent a great deal of last year doing their own things, and it wasn’t until the late fall when they were able to completely focus on recording “One Two,” at a studio tucked away in New Hampshire’s White Mountains.

“At one point earlier in the year, we’d met up in Scotland to work a lot on creating and arranging sets, and it was a great experience,” says Chaimbeul. “I think that energy carried over to when we got together again to make the album, so it made it easier for us to regroup and focus on recording. That was very satisfying – I think it showed how strong our connection is.”

“The studio is part of someone’s home, so it had a very welcoming atmosphere,” says Moynihan. “We spent four days recording, and it was nice to make full use of that time, and not rush to get it done – we had a lot of dance parties and plenty of good food. Definitely another good bonding experience.”

This year has seen somewhat less separation for Moynihan and Chaimbeul (although this fall Moynihan has been on the road with the Dance Cards and Chaimbeul had an extensive tour with The Aerialists). Later this month, they’ll be at the Scots Fiddle Fest in Edinburgh, before Moynihan begins preparing for this year's “A Christmas Celtic Sojourn” show.

Musing on their busy joint and individual itineraries, Moynihan says, “There was a time early on when we didn’t think too much about getting gigs, especially because Mairi was still a student. We were just making music because we wanted to, and there was no pressure with having to book a tour – or about whether anyone actually liked what we were doing. So we got used to the music just being an organic part of our lives, and I think that helped a lot in building our partnership.

“Now, we may sometimes be off making music with other people, but then we come back to the house we share with a bunch of musician friends, reconnect, and it feels as natural as it ever did.”

[Learn more about Jenna Moynihan and Mairi Chaimbeul at jennaandmairi.com]