It was nearly 5 p.m. Time to break a world record.
"Follow the bows of the people in front of you," shouted Robert Halczyn, a music teacher at Williams Middle Magnet School, perched atop a ladder. Even using a megaphone, he could barely be heard over the rumble of teenage voices and the tuning of violins, cellos, basses and violas.
Eight hundred fifty-eight student musicians and teachers from Hillsborough County had turned out Wednesday afternoon to take part in a whimsical challenge: earning a place in the Guinness World Records for the largest ensemble of string instruments. At 5 sharp, they would take a crack at Johann Pachelbel's Canon, a classical piece from a 17th century German that they'd never played together until now.
"It's hot outside," said seventh-grader Julia McKernan of Benito Middle School. "I'm hoping it sounds good."
It needed to. The Guinness people had given explicit instructions, Halczyn said. To qualify, there had to be one registered observer for every 50 participants, news coverage, and independent video to document the performance. And they couldn't just scratch out the tune and hope to land in the big book.
"It actually has to have a good quality to it," Halczyn said.
He hadn't been aiming for such an ambitious production when he sent a query to the London-based Guinness, wondering whether a combined student-alumni performance might be noteworthy. They wrote back to suggest the big orchestra mark - a mere 392 instruments - established last spring in Washington State.
"I said, 'Well, if we get other teachers involved, we could break that,'" Halczyn said.
The proof was arranged around him Wednesday on the school's tennis courts.
More than a dozen bass players took up residence on one court. The fact that many wore sunglasses served only to emphasize the self-evident coolness of their chosen instrument.
"Bass is the instrument to play!" Robinson High sophomore Frankie Flores announced.
Over in the violins, 14-year-old Samantha Brewer of Riverview High tuned up her standout instrument: It was pink.
"I think it's pretty sweet," said her friend and stand-mate, 16-year-old Cathy Rodriguez, surveying the scene. "I think it's nice that people are so interested in orchestra. I don't know why it's always on the chopping block."
All around the improvised concert hall, parents and onlookers craned and pointed cameras through the chain-link fence.
"My granddaughter is out there," said Mary Collins of Brandon, fairly hopping with excitement and pointing into the violin section. "This is a chance in a lifetime for her."
Halczyn's arms went up, and 858 musicians quieted down. They'd rehearse once, and then try for history.
The basses rumbled to life, and around the courts, parents' mouths opened with delight. Then the violins, violas and cellos joined in. They were off.
Halfway through the rehearsal, a piece of music fluttered off the stand. In the back row, an overheated girl sat down to drink some water as a teacher fanned her.
But everyone else was playing Pachelbel. They were in tune. They were an orchestra.
Seven minutes later, after a short break, Halczyn hands went up for the last time.
"Now we're going to do it for real," he shouted.
The basses rumbled again - a bit faster than the violins this time, and for a moment it seemed like the two sides of this orchestra might come unglued.
But Halczyn waved his arms a bit harder, exaggerated his motions, and like good musicians, 858 sets of eyes flickered up from their music to their conductor. They came back together.
As the song reached its conclusion, 14-year-old Ally Spruill of Williams Middle looked up from her music.
Still playing her viola - closing in on her world record, if the Guinness folks agree - she smiled her way through the final notes.
Tom Marshall can be reached at email@example.com.