It begins, by bluegrass standards, fairly simply - a whispered count and a salvo of quick-picked banjo. As the song, a spirited version of the classic Orange Blossom Special, progressed, more instruments are woven into the arrangement - a softly plunked upright bass, the rhythmic strumming of an acoustic guitar and the high, lonesome call of the fiddle.
As the combo, a local bluegrass collective known as Savannah River Grass, rounds the bend into the second verse, sonic filigree is added - improvised guitar breaks, looping bass fills and fiddle sounds that recreate the haunting sounds of a train steaming through a black Southern night.
And then, as quickly as it began, the song finishes. The men, four of the six regular Savannah River Grass members, look at each other a little breathlessly, but with faces split by warm smiles.
"A little cold, but not too bad," says banjo player Tom Lowery. "Not bad at all."
For the members of Savannah River Grass, bluegrass means more than being able to play a mountain tune. It's an exploration of America's musical historical record, an opportunity to educate, preserve and entertain.
"This is pure American music," said Ronnie Davis, the band's bass player. "And either it calls to you or it doesn't. But for us, there is nothing like a great bluegrass jam session. It's hard to describe, but this is a kind of music that flows out of you."
Instinctual and uncharted (bluegrass is rarely played off sheet music), bluegrass combines the rhythms of Celtic music and the improvisational style of jazz with the aural hallmarks of country and the blues.
"Yeah, there's a lot of blues in this," said guitarist Darryl Hudson. "There's an expression in blues music that says when it's good, you should be able to hear those people hurting. Bluegrass is like that.
"It's a passed-down music, like the blues. It's a music that came from hard times, from not having a lot of luxuries, and you can hear that."
The world of bluegrass operates as a sort of pure democracy. Inexperienced players are encouraged to pick up their instruments and join in with more seasoned musicians. The songs are arranged and played in such a way that everyone gets a moment in the spotlight.
"When we present this music, we try to present it as a blend, a mix that works dynamically," Mr. Davis said. "Rather than getting up there and everybody playing at once, we try to showcase each instrument and the varied sounds of a bluegrass band."
WHAT: Savannah River Grass
WHEN: 8 tonight
WHERE: Borders Books and Music, 257 Robert C. Daniel Jr. Parkway
ADMISSION: Free. For more information, see the Web site www.savannahrivergrass.com
Reach Steven Uhles at (706) 823-3626 or firstname.lastname@example.org.