You can't blame Straight No Chaser founder Dan Ponce for having mixed feelings about holiday music.

"Given that our two nationally distributed albums [2008's "Holiday Spirits" and this year's "Christmas Cheers"] are both in the vein, the season can't start early enough for us," Ponce shared with a laugh in a recent chat, prompted by the 10-man a cappella group's return to the Keswick tonight for a sold-out show.

Then again, on a twisted ditty like "Christmas Can-Can," you'll hear the guys grousing lyrically that they have "heard this same [Christmas] song 20 times and it's only Halloween."

The reality is that SNC's most active touring schedule is in November and December. That's when ears are ripest for their fun, fresh, vocals-only takes on jingly bells and child a-bornin' classics like "We Three Kings," kick-started with a "Mission: Impossible" bass line and then some stuttery reggae jammin'. Or their smooth R&B rendering of "Let It Snow." Or the Memphis-barbecued "Santa Claus Is Back In Town," performed by band member Ryan Ahlwardt as a full-on and funny Elvis Presley.

Between verses, "The King" waxes ecstatic about pig's feet-flavored eggnog and candy canes made of mayonnaise. "And uh, Merry Christmas very much, baby."

Also piling it on for the merry season, Straight No Chaser has a PBS special "Live in New York: Holiday Edition." Seen last weekend on the Lehigh Valley outlet WLVT-39 (it ran earlier this month on WHYY), the concert showcases them as a hip and handsome, vocally nimble and aggressively playful bunch.

Think Michael Buble multiplied by 10, minus the brassy backing band. Or see for yourself on Christmas morn, when the SNC troupe will make multiple appearances on NBC's "Today" show.

Despite all this, Ponce wants it known that Straight No Chaser is not ready to be put back in storage in a couple of weeks.

"While we started out tentatively as a group, we've now dropped other things, committed to this full time," he said. "Even right now, half our stage show is non-Christmas music. And we're looking forward to December 26th, when we can fully shift the focus back to the other music we do."

Gotta get some momentum going for SNC's first "all pop" Atlantic album, due out in the spring and tentatively titled "With a Twist." It promises a mixed bag of material "from '60s Motown to rock band stuff by Oasis and Red Hot Chili Peppers."

Ponce put Straight No Chaser together in 1996 as an undergrad on the Indiana University campus. "We were the first harmony group at the school, but relative latecomers to the a cappella scene," he said.

In fact, student choral groups that juggle a hodgepodge of material (pop, jazz, classical, spiritual) with only their voices as the instruments have been popular on campuses - especially in the Ivy League - for decades.

At a school like Yale (famous for its 100-years-young Wiffenpoofs), "you'll now find as many as 15 different singing groups," Ponce said. Nationwide, there are "probably about 350 a cappella groups floating around on campuses."

But Straight No Chaser - the first and so far only to jump out as a charting pop phenomenon - was different from the start. They were cast not only for singing abilities and diverse tastes but also for their ability to goof on stage, to seem "like a bunch of guys hanging out in a bar, having a few beers."

The group's name is a taproom term for alcohol served "neat," without ice or other embellishment. It's also the name of a very cool Thelonious Monk jazz tune, "but we weren't thinking of that," Ponce allowed.

As undergrads, the group put out a couple of indie albums and played some off-campus dates. When Ponce and most other members were graduating in 1999, they enlisted a new crop of student singers to carry on the tradition (that undergrad SNC group still exists on campus) and went off to do other things.

"One guy became a financial analyst. I was a reporter for the ABC-TV station in Chicago. And one of our most talented guys, Jerome Collins, performed in 'The Lion King' and at the Hong Kong Disneyland," Ponce said.

In 2006, the original crew was invited back to their alma mater for a 10-year anniversary SNC reunion concert. Another founding member, Randy Stine, put together a DVD of past performances to mark the occasion, and one of its videos posted on YouTube started getting lots of hits - their goofy take on "The Twelve Days of Christmas," jumbling the dates, throwing in "I Had a Little Dreidel" and mashing in some of Toto's hit "Africa."

By Christmastime, the clip had become one of YouTube's biggest draws, garnering seven million views. One of the gawkers was the CEO of Atlantic Records, Craig Kallman, who e-mailed Dan on New Year's Day proposing a contract. Ponce initially thought it was a prank, but the group ended up with a five-album, "360" deal. In today's parlance that means the label makes money from everything the artist touches - extra incentive to promote the heck out of the ensemble.

These days, Kallman is looking prescient.

Lively choral style renderings of pop tunes are a major element of this season's Fox TV hit "Glee." And just this week, NBC staged a well-rated, multi-night talent contest, "The Sing-Off," devoted strictly to a cappella harmony groups.

One of the show's producers, Deke Sharon, is an SNC collaborator. (The finale is at 8 p.m. Monday on Channel 10.)

"I think what Craig saw in us was the same reason the public is now embracing this music," Ponce said. "People are ready for a natural, organic sound. There's been a trend lately to overproduce music with special effects and vocals that sound less and less human - that whole Auto-Tune thing. With us, there's nothing to hide behind. What you see and hear is what you get. "

Straight No Chaser performs a sold-out concert, 8 tonight at the Keswick Theatre, Easton Road and Keswick Ave., Glenside, 215-572-7650, keswicktheatre.com.