Straight No Chaser has been known to get a few double takes in concert when audiences hear a bass line and rhythms, but see only singers on stage.

Straight No Chaser has been known to get a few double takes in concert when audiences hear a bass line and rhythms, but see only singers on stage.

"It's just the 10 of us, 10 mics, that's it," vocalist (what else?) Walter Chase says during a telephone interview. "Even on the album, what might sound like a drum machine, that's all vocal percussion that has been engineered.

"That stems from our main vocal percussion guys, Tyler Trepp, Seggie Isho, Dave Roberts, myself, (and) Randy Stine," Chase said. "Tyler specifically, like on our holiday set he does the sound of a sleigh bell. It's uncanny how well he can imitate things. Seggie does amazing beat box, like old-school beat box. If halfway through a song you're performing it live, you almost forget that somebody's over there drumming with his mouth. It sounds like you've got a rhythm section behind you."

The vocally produced rhythm sounds are just one of the facets of Straight No Chaser that makes the group unique. As singers, the 10-man a capella group creates a pretty special blend as well.

That much is apparent on the group's latest CD, "With A Twist," in which Straight No Chaser plies its vocal talents to a diverse set of a dozen covers.

A version of Crowded House's song "Don't Dream It's Over" captures the full range of sound, from layers of vocals to a realistic sounding bass line and percussion. The group also builds a surprisingly full sound on the '60s nugget "Tainted Love," which was made famous in the '80s by synth-pop group Soft Cell. Perhaps the big highlight comes when Straight No Chaser combines Jason Mraz's "I'm Yours" with "Somewhere Over The Rainbow," playfully mixing lyrics and melodies from the two songs. But on a few songs, such as Coldplay's "Fix You" or Oasis' "Wonderwall," it feels as if the vocal arrangements could be more imaginative, and Straight No Chaser could have taken a few more risks in reworking certain songs. But there's no disputing the vocal talents of the group members or the magic they create during the best moments of "With A Twist."

Speaking of magic, the way Straight No Chaser reached its current place as a nationally touring major label recording act is pretty amazing in its own right.

For most of the past 15 years, the only Straight No Chaser that existed was one made up of college students at the University of Indiana in Bloomington.

Six of the 10 members of today's vocal group were in the inaugural edition of Straight No Chaser that formed at the Big-10 school a decade and a half ago.

When graduation came for the original vocalists, they went their separate ways never expecting that the group would be a part of their lives again.

That changed when the University of Indiana decided to have a reunion of the original members in 2006. To help mark the occasion, Stine posted a video on YouTube of a 1998 concert that included the vocal group's wacky rendition of "The 12 Days Of Christmas."

To everyone's surprise, the video went viral. By December 2007, views of the video had reached seven million. One of those who tuned in was Craig Kallman, CEO of Atlantic Records, who called Stine to discuss a record deal.

"Randy thought it was a joke, had to Google him (Kallman) online," Chase said. "But it really was him. A couple of weeks later, the entire group is at Atlantic Records speaking with Craig and the higher-ups, and they were telling us that they wanted us to do a five-album record deal with them."

Because of the success of the "12 Days Of Christmas" video, Atlantic had Straight No Chaser debut with a Christmas album," Holiday Spirits," in 2008. Straight No Chaser was off and running, and last year the group released a holiday sequel, "Christmas Cheers." That CD included a mix of new tracks and songs from "Holiday Spirits."

The success of the Christmas material forced Straight No Chaser to postpone its plans to make a full CD of pop material. The group released an EP, "Six Pack," last year, but only now has the long-planned "With A Twist," arrived in stores.