BOSTON--Amid the packed crowds waiting for the train to arrive at T stops throughout the city, impromptu performers and entrepreneurial guitar players set up shop, hoping for coins or song requests.

For Jack M. Maher and Daniel S. DePoe, a duo who performs in the Park Street stop, subterranean jazz sets and Christmas carols can bring in the occasional gold ring, as well.

Maher, a guitar player and singer, and DePoe, a trumpet player, took their act underground several months ago, playing jazz arrangements of Christmas carols for the holiday season.

The money was so good and the experience so entertaining, they say, that they came back for more.

Now DePoe and Maher, who play together under the name Amusia (a disease impairing the ability to understand music), play in the Park Street and Government Center T stations regularly and say they have never been happier.

DePoe, who has been playing the trumpet since he was a child, says he quit a job waiting tables because he is now able to make as much, if not more money, playing in the subways.

"It's like when you were a kid and all you wanted to do was go play," DePoe says. "Now I can go play whenever I want."

Maher, a recent graduate of the Berkley College of Music and a member of the band Bobby Lee Rodgers and the Herd, says he feels the same way.

"If I live this way for the rest of my life, I'm sure to be happy," Maher says.

The 23-year-olds try to spread their enthusiasm, aiming to please the diverse clientele.

"I'll play anything, anywhere, anytime, for anyone," Maher says.

DePoe, who cites Nirvana, Foo Fighters, Tori Amos and Miles Davis as his main musical influences, agrees that the two have an eclectic style. He says that sometimes he even steps in to sing when Maher takes a bathroom break.

"I feel obligated to play a song because everyone's staring at me," DePoe says. "So sometimes I sing Nirvana really bad on purpose."

But even then, DePoe says, passersby still toss money into the open guitar case.

Their pastime is not only pleasurable, but profitable.