"It's like a palette for artists," he noted. "It is not often you get groups that experiment with vocal colors. We try to specialize in making this sound so interesting. ... We try to make the hairs on the listener's neck stand up."
That quality to The King's Singers' music is one of many that should bring audiences to the Norton Center for the Arts Wednesday. Another is the variety to the program. The King's Singers, which were formed in 1968, recently released a Christmas album, King's Singers Christmas, their first in 10 years, Connolly said.
"We didn't do it in the studio," he noted, adding the CD is selling fairly well so far. "For this, we went into a church, which was going back to all of our roots. It was really like 'The King's Singers Unplugged.'"
Of why he recommends the performance, Connolly added wryly, "You can't have a Christmas without it."
"The first half (of the performance) will be a lot of carols and Christmas songs from around the world."
The second half of the show will be seasonal music, culminating in "our funny comedy and schmaltzy Christmas songs," Connolly said.
"I was going to say American favorites - all those ones you invented, such as 'Jingle Bells.' ... There's something for everyone in this show. You can go see 'The Nutcracker,' but this is some of the most beautiful, if obscure, Christmas music, sung by six Englishmen making complete fools of themselves."
But being part of The King's Singers is a treat, Connolly noted.
"It's a great privilege to be part of a group like this," he explained. "We sing to all sorts of people. We've been all around the Far East, Europe, America, Canada. We're traveling all around the world, and wherever we go in the world, whatever level it is at, the singing is appreciated.
"Basically, anybody can sing, to a certain extent. We travel to Hong Kong or Singapore and see the look of recognition on those faces."
But being in the United States has its own particular thrill, added Connolly, who has been with The King's Singers for 16 years.
"There is such a high standard for choral singing in the States. There are choral directors and choirs in the schools. People get rewarded in an artistic way, which is good."
Connolly feels rewarded in his career choice. As a teenager, he was a fan of The King's Singers. Before that, he was a boy treble chorister in England, he said, as were the other members of the a cappella group.
"The thing about The King's Singers is that we were in music from a very early age," Connolly noted. "We were singing every day. It's a peculiar English thing that happens.
"Then there's a funny change that happens when you're singing treble and you start singing tenor or bass. I went on to study singing in college."
But it's a challenging career as well, he added.
"The traveling is difficult, being away from home six or seven months a year," said Connolly, who has a wife and two children back home. "I'm in New York now, but yesterday morning I was in Devonshire, in the southwest of England. I'm fairly wiped out at moment. We're in New York just for today."
The jet lag was pretty fierce Wednesday night - England is five hours ahead of the East Coast.
"It was 7:30 p.m. when we arrived, and I thought, 'I can't just sit in my room,'" Connolly said. "So I walked down Broadway to see the celebration. ... I saw the turning on of the Christmas lights last night.
"I went to sleep at the equivalent of 5 a.m., England time. It's good to have a day before we start singing because of the jet lag. But it's worse going the other way."
So while getting over jet lag and preparing for the American tour, Connolly and Co. focused on what The King's Singers were bringing to American audiences - a diverse and difficult-to-describe repertoire.
"We sing so many (styles of music)," Connolly noted. "The King's Singers really are unlike any other group in the world. The music dates back to the 13th century up to present day. We sing arrangements of pop music and commissions especially written for us.
"We happened over the years to develop these broad tastes. You might hear Renaissance music or something from a Queen CD."
For more information on The King's Singers and their newest CD, go to www.kingssingers.com.