TAMPA ó The Florida Orchestra hosts a throwback party this weekend with a baroque theme. Thatís two harpsichords, a smaller ensemble on stage and an effort to play in the style of 17th-century musicians. Things kicked off Friday at the David A. Straz Jr. Center for the Performing Arts, where conductor Jeannette Sorrell gave the audience a history lesson that wasnít the least bit dull.Johann Sebastian Bach got his due, most memorably in the Brandenburg Concerto No. 3 and the overture to his Orchestral Suite No. 1, and so did Antonio Vivaldi, with whom this polite, relaxed evening closed on a festive note. In between came Georg Philipp Telemannís Don Quixote Suite and his Grillen-Symphonie, the first time the orchestra has played either piece.Sorrell, who founded the antique music ensemble Apolloís Fire, comes to town with a pedigree in historical performance (a genre insiders simply call "HP"), having studied harpsichord with Gustav Leonhardt, the Dutch musicologist who might have done more than any other modern authority to rescue 17th-century baroque music.In his twenties, Sorrell said in a preconcert talk, "Gustav Leonhardt went into the library in Vienna, and spent eight hours a day there for a year, copying out manuscripts that in those days could not be taken out of the library."Differences between baroque style and modern include all musicians but the lower strings standing up (including Sorrell, who also played harpsichord), and playing with little or no vibrato. A string playerís expressiveness from the right hand holding the bow, not the left. Notes tend to begin forcefully and tail off, a phenomenon Sorrell calls "whale" notes for their acoustical shape. You notice that attacking style immediately. In the first movement of the Don Quixote Suite, for example, Cervantesí hero "awakens" to the groaning of the double bass, a friction that touches you in your seat.The Grillen-Symphonie echoed the eveningís informal feel, informed by Telemannís hint that it starts with flirtation and builds to a party scene. Piccolo and double basses might reflect young and old crickets, Sorrell suggested, playing off of the German "grillen" meaning either "whimsical" or "crickets."As for Bach, it seems unbelievable now the composer died in relative obscurity. The Orchestra Suite, set to a series of Italian and French dances, reverberates joy, violins like a racing brook as two oboes and a bassoon complete some algorithmic equation.Sorrell conducts expansively in such moments, clearly in her element."Bachís goal was to move the emotions of listeners," she told the audience. "If after the end of two hours you feel better, we will have done our job."The concert took historical performance to another level in the Vivaldi, which the composer originally scored for just two violins and a viola. The orchestra played Sorrellís own arrangement, which puts many string players on the stage but keeps the playful feel.The Brandenburg Concerto No. 3 also added a delightful touch. The composer scored the slower second movement in only two chords, confident musicians would feel free to improvise. Before the piece, Sorrell told the audience she had left the door open to improvisation and that "nobody knows whatís going to happen."Then at the top of that movement, the conductor played a few bars on the harpsichord. She glanced at concertmaster Jeffrey Multer, who replied with an unwritten phrase on the violin, and at principal cello James Connors, who followed suit.Contact Andrew Meacham at [email protected] or (727) 892-2248. Follow @torch437.