During this time, Seattle Pro Musica became known as a leader in the "authentic performance" of Baroque music, especially Johann Sebastian Bach's.
Sparks conducted Seattle Pro Musica in Claudio Monteverdi's Vespro della Beata Vergine at St. Mark's Cathedral and Handel's Messiah.
[2] In the early 1980s, Sparks grew interested in Swedish choral music and the work of conductor Eric Ericson.
He remained there until 2001, during which time he directed the choir in Benjamin Britten's War Requiem, Bach's Mass in B Minor and St. John Passion, Igor Stravinsky's Les Noces, Sergei Rachmaninoff's Vespers, Johannes Brahms's Liebeslieder Walzer, and Giuseppe Verdi's Requiem.
[3] In May 2021, Sparks was one of 10 new members elected to the Royal Swedish Academy of Music, alongside Marika Field, Katarina Karnéus, Jonas Knutsson, Sten Sandell, Đuro Živković, Keiko Abe, Giancarlo Andretta, Stefan Dohr, and Quincy Jones.