The raw, slamming sounds of girl Band A reverberate liked trapped thunder against white cinder-block walls.
Standing in a circle - rock-and-roll poses perfected, little-kid smiles wiped away - each girl adds her personal noise to the collective din, now growing loud enough to kill small animals.
At Girls Rock Philly day camp at Girard College this week, the first all-girl rock camp in the Philadelphia area, you don't ask if it's good. The questions are: Is it awesome? and Does it rock?
"Thank you, America!" cowboy-booted lead singer Emma Ragsdale, 10, of Merion, intones when the rumbling ceases and the windows stop rattling. She appears to be acknowledging applause heard only in her head.
"Of course, as you know," she goes on breathlessly, "I'm the lead singer. When I grow up, I'm going to be a famous singer and play all over the world and help people."
The girls look happy. And that's pretty much the whole point.
If children are to be seen and not heard, girls especially must remain forever silent.
At least, that's what too many people believe, according to Beth Warshaw, volunteer director of the $400-per-child, weeklong camp.
"The empowering thing is to make noise," says Warshaw, a producer at WXPN-FM (88.5), "which girls and women are discouraged from doing."
Thanks to donated Fender amplifiers and tough-skinned drum kits, these kids are, above all things, profoundly empowered.
"I love it," says Emma's pal, tiny blond guitarist Becky Dame, 11, also of Merion.
"I know, it's so awesome," Emma agrees.
Around 100 summer camps in the United States are specifically devoted to rock music, and about 5,000 camps incorporate some aspect of rock playing or instruction, according to Jeffrey Solomon, executive director of the National Camp Association.
"But a rock camp just for girls is unusual," he adds. Girls Rock Philly is one of a handful of regional girls-only rock camps that belong to the nonprofit Girls Rock Camp Alliance, based in Portland, Ore., and founded in 2000.
The alliance is probably the only girls' rock-camp organization in America, Solomon says.
These days, of course, rock is not so much a rebellion as an everyday activity. Fifty years of jangling guitars and shouted lyrics have universalized the art form.
Even your grandmother could pick Mick Jagger out of a lineup. She may, in fact, have dated him.
