"Once I did a series of paintings that were just treetops," says drummer Billy Beard, "and you couldn’t quite tell what they were hiding. Maybe Baby’s music is like that to me. Here’s a mystery and you have to enter it. It’s inviting and organic, but there’s something dark behind what’s on the surface. So playing with these guys, I get to explore mysteries."

The "guys" in question are Jennifer Kimball and Ry Cavanaugh, two of the local folk scene’s more respected singer-songwriters. They started collaborating as Maybe Baby three years ago, and they quickly drafted veteran Beard as a musical partner.

"We wanted to challenge the definition of folk music," says Cavanaugh, who does his part by playing baritone guitar through a variety of electronic stompboxes. "My vision was to get a little more trippy and to emphasize the low end. Billy and his cocktail [drum] kit are perfect for that."

Indeed, Beard’s thumping stand-up drums — the kind designed decades ago for cocktail lounges too intimate for the volume of a full kit — add bass notes and a purring low-end tonality to Maybe Baby’s sound. And when the band are playing a gig in full bloom — not just as a trio but with, as is often the case, the exploratory guitar of Duke Levine or Kevin Barry and Dana Colley’s throaty saxophone or Kris Delmhorst’s singing fiddle — that sense of mystery is enveloping.

It’s also thoroughly present on their self-released debut album, What Matters. The first two numbers present Cavanaugh and Kimball as the group’s songwriting yin and yang. Cavanaugh’s "April" has a wistful, homespun feel colored by Kimball’s acoustic guitar, his own spare baritone six-string and dusty voice, and drums that gain momentum as splashes of electric guitar and organ are added. The number is a charming, sad-edged example of the more traditional folk bent of Cavanaugh’s writing.

Next, Kimball’s "Be My Baby" reveals some sharp pop instincts. It’s a song about a crush set to a sprightly medium tempo that bounces beneath her clear-toned vocal melodies. But with the third number, "Little Live Things," the mystery sets in. Levine adds moaning slide guitar as Kimball contrasts the pain of mourning with the bright blossoming of spring. The tune continues to play with that duality of bright life and dark shadow, particularly during an instrumental break in which organ, guitar, and sax combine for a swirling passage that wouldn’t sound out of place on a vintage Pink Floyd album. "Icarus," Cavanaugh’s tune about emotional withdrawal as the cost of nurturing dreams, also benefits from Levine’s edgy, atmospheric playing, which provides a glimpse into the frightened part of the narrator’s psyche that keeps him from opening up to the woman he loves.

And so it goes. Electric guitars, organs, mandocello, banjo, harmonica, and other assorted instruments combine to form a third voice, one that tends to have a subliminal effect. Operating at a volume well below the salient chords and melody lines, these whispering instrumental flourishes enhance the air of mystery.

Maybe Baby got their spark when Kimball and Cavanaugh met one night at the Brendan Behan pub in Jamaica Plain. The formidable Iodine Brothers, a band featuring guitarists Levine and Barry plus local singer-songwriter Dennis Brennan, were playing. As is often the case, there was a large number of other musicians in the audience. Kimball had recently left the Story, a successful folk duo in which she sang harmony with Jonatha Brooke; Cavanaugh was in the acoustic outfit Vinyl Avenue. The friendship they kindled that evening grew into a full-blown romance and, eventually, the musical collaborations that evolved into Maybe Baby.

Kimball had only just started writing her own songs at the time, but now she and Cavanaugh act as Maybe Baby’s equal but opposite creative poles, giving the group’s repertoire a sense of tension and contrast even when they’re doing a gig as a duo. "That’s one of the things that keeps it interesting and fun for me," says Kimball. "Between the instrumental approach and our identities as songwriters, Maybe Baby isn’t predictable, and it can be a challenge for people to get a hold of in some ways. And with so many friends who are great musicians to draw on, we can play as a duo, as the trio, a quartet . . . whatever configuration we choose."

For the most part, getting a bead on Maybe Baby seems toughest for the people running folk coffeehouses. "When I show up with an amplifier, my baritone guitar, and a bunch of stompboxes, I can see them start to cringe," says Cavanaugh. "Later, when I listen to the tapes from the soundboard, all I can hear is Jen’s acoustic guitar."

So far the larger version of the group has gotten its warmest reception at the Lizard Lounge and Toad (both of which Beard happens to book). But Kimball and Cavanaugh are scouting out new locations for full-fledged Maybe Baby shows. Earlier this year they played Capo’s in Lowell as a duo, and they were so well received, they’re planning to return with the fleshed-out band.

LIKE WHAT MATTERS, Bourbon Princess’s Black Feather Wings (Accurate) was recorded at Hi-N-Dry, a fifth-floor aerie in an old Cambridge industrial building that’s more like a comfy loft apartment than a studio. The place’s warmth and atmosphere translates to the recordings made there, which date back to Morphine’s Cure for Pain (Rykodisc) and include recent albums by folksingers Karaugh Brown and Kris Delmhorst and rockers the Twinemen.

The latter band’s nucleus is vocalist Laurie Sargent and ex-Morphine members Dana Colley and Billy Conway. Colley and Conway tend to take turns manning the studio’s controls: Conway produced What Matters, for example, and Colley, along with Monique Ortiz, produced Black Feather Wings.

Bourbon Princess is in essence Ortiz, who writes the material, sings it, and plays fretless bass. The name refers not to any predilection for Jack Daniel’s but to a consort of the Marquis de Sade, the Princess of Bourbon. "Sometimes it’s really annoying, because I can’t enjoy a whiskey without somebody saying, ‘Bourbon princess, eh?’ " The name does create a sense of mystery, and so does Ortiz’s music. But it’s deeper and darker than that of Maybe Baby — closer to the poetic "low rock" of Morphine. At times, in numbers like "The Spider Sings" and "The Dream," Ortiz sings with long, deep phrases that recall Morphine’s late vocalist, Mark Sandman.

And there is a connection. Ortiz was living in Lancaster, Pennsylvania, in the mid ’90s and going through a difficult period. Her band, a new-romantic-inspired group, had just broken up; worse, her brother had died, sending her family into turmoil. His passing occurred just before Ortiz went off to college, so she soon found herself alone and miserable and trying to find her own way out of an emotional pit. Morphine offered her a rope ladder.

"Amid all this other stuff, I was trying to figure out what I was going to do musically," she says. "I knew it wasn’t going to be a band with a guitar, but I didn’t know what it would be. And then I saw the movie Spanking the Monkey. I heard the soundtrack and loved the band. I didn’t know what instruments, exactly, were playing, but I knew they didn’t have a guitar."

The music for Spanking the Monkey was provided by Morphine. Shortly after she figured that out, Ortiz learned that the band had a show scheduled at the Trocadero in Philadelphia and determined to go. "You know how sometimes music will just hit you at the right time and make you really examine what you’re doing? I realized I was going to change my life at that Morphine concert." After the show, she went behind the club and met Sandman as the band were loading out. "I don’t know if he was just striking up a conversation or had some kind of inkling, but he asked me, ‘Are you a musician?’ I ended up telling him where I was at, and he tilted his head and looked at me kind of sideways, all chiseled in that Sandman way, and said, ‘Sounds like you need to relocate.’ "

Sandman advised her to check out Cambridge, and in 1996 she did move there. What’s more, she pulled together a dream line-up for Black Feather Wings. Colley plays saxophone all over the album, and the drummer is Jerome Deupree, Morphine’s original sticksman. They’re joined by guitarist/pianist Jim Moran. Deupree’s swinging, spare style of propulsion and Colley’s low-toned sonorities make comparisons with Morphine inevitable.

But careful listening reveals that Ortiz has evolved her own style as a talented poet since her self-released 2000 recording Stopline. Her songs, whether spirited kissoffs like "I’ll Take a Cab" or pure narrative like the post-one-night-stand "Early Train," are full of vibrant detail. The original blues tune "Careful What You Wish For" reveals her true range as a singer: Ortiz likes to keep her voice low for most numbers, and that adds to the sultry ambiance, but on "Careful What You Wish For" she unveils her upper register, with delicate phrasing and subtle control.

Although Black Feather Wings is an excellent album, Bourbon Princess are best straight up — live. That’s where Ortiz’s stories get a boost from her energy as a performer, and where her musicianship is on fiery display. As she relates intricate tales like the bleak overdose narrative "Stretcher," she negotiate effortlessly the twists of the fretless bass. The instrument’s slithery tones work almost as a second vocalist, harmonizing with her vocals as Deupree keeps things afloat.

You wouldn’t know it from watching her, but playing a fretless bass while singing is, as Ortiz admits, no easy task. "I find it really, really hard, and I’ve worked really hard to be able to do it. But I can’t even listen to a fretted instrument now. The fretless has just become such a big part of what I do."

Maybe Baby perform as a quartet with Duke Levine every Tuesday in July at Toad, 1912 Massachusetts Avenue in Porter Square. Monique Ortiz appears with Bourbon Princess at T.T. the Bear’s Place, 10 Brookline Street in Central Square, this Monday, July 7, and solo at the Brookline Arts Center, 86 Monmouth Street in Brookline, on Wednesday July 16. She also plays with Bourbon Princess at Zuzu’s, 474 Massachusetts Avenue in Central Square, on Monday July 28 and every Wednesday in August at the Kendall Café, 233 Cardinal Medeiros Way in Cambridge.