The key song in the Wailin’ Jennys’ repertoire, “One Voice,” was written by founding member Ruth Moody. When the three ladies are onstage, singing this a capella, you’ll learn everything you need to know about why they do what they do:

This is the sound of voices three

Singing together in harmony

Surrendering to the mystery

This is the sound of voices three

Moody and Nicky Mehta put the band together in 2002. The third founder, Cara Luft, has seen been replaced by Heather Masse, but three critically–acclaimed albums, numerous Juno Awards and umpteen appearances on A Prairie Home Companion later, the message is the same: Acoustic music, exquisitely performed by a trio of angelic singers who write a lot of the material themselves.

Because the Wailin’ Jennys also play acoustic instruments – extremely well, thank you – the group is usually referred to as a roots or Americana act (this even though Mehta and Moody are native Canadians, and began the group in Winnipeg).

The second Jennys album, Firecracker, almost topped Billboard’s bluegrass chart in 2006.

At Friday’s Lucas Theatre show – part of a cross–country tour to promote the new Live at the Mauch Chunk Opera House album – the trio will be augmented by multi–instrumentalist Jeremy Penner.

Mehta, who also maintains a healthy solo career, called us from her home in Winnipeg this week. The mother of eight–month–old twin boys, she had just finished placing a complicated and frustrating phone order with a baby–food company.

Surrendering, as it were, to the mystery.

OK, I have to ask you about the band name. I understand it was either that or the Folk Vixens.

Nicky Mehta: (laughing) It’s not a great story as to how we got the name. We had very little to do with it. It was the name that the guy that put on our first show came up with.

It’s hilarious – people still sometimes think they’re coming to see Waylon Jennings.

But he’s been dead for eight years!

Nicky Mehta: I know! I don’t get it myself. Well, it doesn’t happen all the time. But the few people that have come, thinking they were seeing Waylon Jennings, have actually stayed. And that’s a big compliment.

You were originally going for a degree in communications – music’s a lot more fun, isn’t it?

Nicky Mehta: It was not your typical communications degree; it was actually more like cultural studies, so it was theory–based. And it would’ve meant I could go on and do a lot of academia, and not a whole lot of practical things.

There’s a professor from my university who is a big fan and comes to tons of shows. He travels a lot, so he shows up in all these different places. And he always makes a point of saying that I made the right choice, mainly for my happiness.

Really good a capella singing just stops my heart. How much work goes into that for you?

Nicky Mehta: It’s interesting, it’s all pretty natural for us. I think we all hear it by ear, and those guys – Heather and Ruth – both have a lot of training. Ruth has perfect pitch, and all of our pitch is pretty decent. But I think everybody naturally hears it by ear. I only do by ear; I don’t have any formal training. I was just lucky. I naturally have an ear for harmony, which is really great. It’s a great thing to have.

So I don’t know what I’m singing half the time, but I just sing what I hear.

If somebody comes in and says “I’ve got this song,” whether it’s an original or a cover or whatever, we just go from the melody – somebody sings the melody – and we just sing. You figure out where you’re going to be, because people move around all over the place ... that’s all kind of organic and spontaneous, and then you go back and refine. I guess the work comes in there – the editing after the fact.

Have you been surprised at the global success of the band – in the beginning, were you thinking it would just be a little local thing?

Nicky Mehta: Sure, yeah, it wasn’t premeditated – it was a complete surprise. We had all been doing different things. I had just released a solo album, so I wasn’t at all looking to be part of a band. I had all my solo touring set up, and that’s what I was going to do.

I don’t think anybody thought it was really going to do what it did. And knock on wood, it’s been great, it’s kind of had its own energy. We struggled all the way along to catch up to it. And you can’t really ask for anything more than that. We’ve been really lucky.

Folk music is like a universal language. That must be sort of a comfort to you, that anywhere there will be people who say “This is what I like. This stuff.”

Nicky Mehta: Every culture has its traditional music, so I think people have a familiarity to some degree or another. Even if you don’t think you like folk music, everybody’s grown up, probably on some level, singing kids’ songs. Which often are based on traditional songs. People know traditional songs even if they don’t think they do. And that’s really fascinating because everyone’s been a kid at some point!

I don’t know, I think it reminds people of a time that was maybe a little bit more simple. And people connect with that.
 But then I also think that three–part harmony is something that people really connect to. People love harmony. And it’s really easy to attract people’s attention when you have three–part female harmony. It’s very interesting to see.

Why does Canada produce so many great singer/songwriters?

Nicky Mehta: Often times people ask that specifically about Winnipeg, because Winnipeg has produced a lot of amazing talent.

People talk about “Well, it’s so cold up here, and there’s not much to do. People end up in their basements playing music.” And I think to a degree that’s true, but everybody’s got a computer ... you could waste your time on the Internet, if you wanted to. So I don’t think that’s only it.

My feeling, personally, is that any time I go up north – further north, which is like Yellowknife and into the Northwest Territories and the Yukon – whenever we’ve toured up there, that’s remote and really cold. And that’s not even the most northerly community you can go into in Canada.

But when you go up there, there’s such a sense of creativity, such an awe and such a connection to the vastness of the landscape. And your relative unimportance in that landscape. There’s no mistaking your place in the world when you’re in those places.

We’re northerly as a country, and I think there’s a real sense of a position relative to nature. And I think that’s really inspiring – it puts you in your place, and connects you to the world.

You have a section on your Web site devoted to food. Savannah’s a big food town. Have you ever been here?

Nicky Mehta: You know what, we were there once and we loved it. So excited to be coming back. We went to one place after the show when we were there. I think we had dessert, and it was really good.

Of course, everybody’s completely fascinated that you can walk around with beer, and alcohol in general. But more food recommendations would be fantastic.

The Wailin’ Jennys

Where: Lucas Theatre, 32 Abercorn St.

When: 8 p.m. Friday, April 16

Tickets: $17–$37

Phone: (912) 525–5050

Online: www.scadboxoffice.com