By Alan Sculley
Correspondent

Tegan Quin readily says that the last two CDs she’s done with her sister, Sara Quin, have been dramatically different musically.

Yet Quin says she can listen to a few songs on “The Con,” the 2007 Tegan & Sara CD, and hear songs that hinted at the starkly different sound of their recently released album, “Sainthood.”

“A song like ‘Relief Next To Me’ or ‘Are You Ten Years Ago,’ those songs (from “The Con”) remind me so much of ‘Arrow’ and elements of ‘Night Watch!,’” Quin said, pointing to two songs from “Sainthood.” “We were kind of stunted on ‘The Con.’ A song like ‘Are You Ten Years Ago,’ we tried playing it live and it was a mess because we were trying to make electronic and live drums and electronic and live bass (work together), and it was just like a disaster. Now we play ‘Arrow,’ which is like ‘Terminator 2,’ and it’s like… awesome. People go crazy and it feels so good and it sounds good.”

In fact, Quin said the entire “Sainthood” CD works well in the live setting, which is something she couldn’t say about “The Con.”

“This record is actually a lot easier to translate live than ‘The Con’ was,” she said. “That came from (producer) Chris Walla seeing us play live between ‘The Con’ and ‘Sainthood.’ We did some shows with (Walla’s band) Death Cab (For Cutie), and he said, like when we started pre-production, ‘You guys are a live band, and I want you to be able to take ‘Sainthood’ and be able to play it live and not have to reconfigure anything and not have to necessarily do any additional work to get that working live.’ So it’s been pretty easy.”

Both “The Con” and now “Sainthood” have represented significant musical moves for the twin sisters from Canada. The duo’s 1999 debut, “Under Feet Like Ours,” and the 2000 follow-up, “The Business Of Art,” were largely acoustic albums that gave Tegan & Sara a reputation as a folk-pop act.

But with the 2002 CD, “If It Was You,” and especially the 2004 release, “So Jealous,” it became apparent that the Quin sisters had a more ambitious vision for their music. Those albums expanded on the sonic blueprint of the previous CDs, as Tegan & Sara used more electric instrumentation and diversified their sound into rock/pop terrain.

“The Con” really opened up new directions, as it cut a far wider and more unpredictable stylistic swath. For instance, the song “I Was Married” dispensed with traditional verse/chorus conventions to create an odd, but effective largely solo guitar/vocal song. Even songs that were more conventional had their intriguing quirks, be it in the odd time signatures of “Knife Going In” and “Are You Ten Years Ago,” or through the unusual sonics of “Relief Next To Me” and “Back In Your Head.”

“Sainthood” is yet another bold step. Where “The Con” had its share of acoustic-flavored material, the new CD is edgier, louder, and for the most part, plugged-in electric. Once again, Tegan & Sara delve into unconventional sonic territories, mixing electronics and guitars in songs like “Arrow” (which indeed has a mechanized, futuristic feel) and covering a variety of styles, ranging from the fast-paced rock of “Hell” to the oddly Motownish “Alligator.”

The sisters also get creative with their vocal phrasings, speeding up or slowing down their cadences in smart ways on songs like “Northshore” and “The Cure.”

Despite the many ways in which Tegan & Sara bend and reshape the pop form, “Sainthood” is an accessible album, largely because songs like “Don’t Rush,”

“Northshore,” “Hell” and “Arrow” are also extremely catchy.

But exactly why she and her sister were drawn to an edgier, more rocking sound on

“Sainthood” is something Tegan Quin can’t really explain.

“We wrote this record like we’ve written all of our past records,” she said. “We just kind of went song to song, just keep writing and putting them in the pile. But it seemed when we were picking from that pile, we had over 50 songs, and it seemed we were more attracted to the poppier, punkier, heavier rock songs, for sure. And I can’t explain exactly why that was. I think it’s partly just because we’re playing really big venues and we definitely have been getting more mainstream rock and pop radio (play).”

While Quin said there are still older songs in the group’s live set, she and her sister have worked hard to create a smooth flow to the shows, particularly when it comes to material from the two most recent albums.

“‘Sainthood’ and ‘The Con’ are really different kinds of records, so thinking about how to make those records feel good next to each other has been a big part of creating the live show,” Quin said. “It’s a good mix right now of old and new.”

Tegan & Sara
When: Saturday, Feb. 13, at 8 p.m.
Where: Orpheum Theatre, 1 Hamilton Place, Boston.
Tickets: $33.
Info: 617-482-0106, www.livenation.com/venue/orpheum-theatre-boston-ma-tickets.