Jeff Thacher is a freak, no two ways about it.
The guy makes his musical living playing drums with his mouth, which qualifies him right there.
"People who haven't seen us before tend to look at me and go 'what the heck is … that?'," he confesses.
Thacher's forum for oral percussion is Rockapella, who bill themselves as "the kings of contemporary a cappella."
As the only a cappella group ever to get their own TV series, Rockapella enjoyed a five-year run providing the soundtrack to the hit PBS game show, "Where in the World Is Carmen Sandiego?" (1991-96).
Ostensibly a kids' series, "Carmen" also cultivated fans outside that demographic, due in no small part to the engaging singers, who also appeared on camera, providing comedy, as well as musical, relief.
Several years later, Rockapella scored more pop culture points via a pair of extremely popular Folgers coffee commercials, putting their hip harmonic spin on the "best part of waking up is Folgers in your cup!" jingle.
For the time being, the quintet is headed our way to vocalize on behalf of "A Rockapella Christmas" Saturday night in the Bloomington Center for the Performing Arts.
Group leader Scott Leonard breaks down the instrument-free fellowship thusly: "Four world-class voices - and one freak of nature."
All freaks should be so lucky, by the way: Thacher's vocal calisthenics, which maintain the beat for those four world-class voices, have set him apart from the run-of-the-a-cappella-mill.
The freakishness started, says Thacher, at a tender age: "As a kid, I started making sounds for my toys, including my Lego spaceship. That seemed to go pretty good until they started putting batteries in the toys that made the sound for you, even though they were the wrong sounds."
But he was not silenced.
Coming from a musical family, Thacher says "it was inevitable that I would eventually imitate drums."
During his Berkelee School of Music years in Boston, Thacher co-founded a campus a cappella group with the intention of utilizing his singing gifts.
But he again started fooling around with his vocal percussion novelty and "I thought, gee, this is not as silly as it seems - it actually makes a lot of logical sense."
He headed to Los Angeles, where his connections to the a cappella community put him in touch with Rockapella, founded in the mid-'80s by a quartet of Brown University alumni who made the group's name in New York City by setting rock songs to a cappella sounds on street corners, in clubs and at private parties.
The group's ticket to fame came around 1990, when a producer making a documentary about America's contemporary a cappella scene caught the quartet's act. As a result, he made them a part of the resulting film, which was hosted by Spike Lee and Debbie Allen, and premiered on PBS as "Spike & Co.: Do It A Cappella."
The domino effect continued as yet another PBS producer caught the show. He decided the group would be perfect for a new kids' series in the works, "Where in the World is Carmen Sandiego?," a game show with a geographic/musical bent.
It was midway through the series' run that Thacher was added to the Rockapella mix, upping the quartet to a quintet, and rendering them a breed apart.
Thacher's pretty certain that he's only the second full-time a cappella vocal percussionist, the first having been used in the group True Image.
Make no mistake: "Spitting into the microphone can be exhausting." For the sake of all front-row-sitters, he adds that "it's very focused spitting. In that sense, it's like playing a trumpet for two hours. You have to push from the diaphragm and through your mouth to get the different sounds.
Then, "in the rhythmic sense, it's like being a real drummer - but instead of using your hands, you have to use your instincts."
The stamina required for this merging of trumpet and drum via the vocal cords is no small thing.
Dependent on it are his fellow singers: George Baldi, an alum of the band that became Boyz II Men; Kevin Wright, a New York theater veteran; John Brown, who has shared stages with the likes of Tina Turner and Julie Andrews; and group leader/arranger Scott Leonard, the man behind the shaping of the music.
Oh, yes, one last thing: Kids, don't try this at home. You'll save Thacher a lot of grief.
"I'm always getting moms who come up to me after a show and say, 'my son or my daughter is making all these noises, and it's because of you!' "
"And about all I can say to them is, 'I apologize … I really do.' "
At a glance
What: "A Rockapella Holiday" with Rockapella and Route 66
When: 7:30 p.m. Saturday
Where: Bloomington Center for the Performing Arts, 600 N. East St., Bloomington
Tickets: $22.90 to $34.50
Box office number: (866) 686-9541