Two excellent Philadelphia ensembles, Piffaro and Orchestra 2001, come from opposite ends of musical history: One is dedicated to the joyful recreation of Renaissance music and the other a champion of living composers. The upcoming collaboration of these unlikely bedfellows is a testament, and perhaps a challenge, to our musical imaginations. The catalyst for the event is a new work by Kile Smith, who has written for Piffaro in the past to great acclaim. There will also be contemporary music from Arne Running and the late Jacob Druckman, as well as some ancient tunes for voice, featuring Philadelphia’s (and much of the world’s) favorite baroque soprano, Julianne Baird.

Fri., Feb. 22, 8 p.m., $35, Trinity Center for Urban Life, 2212 Spruce St.; Sat., Feb. 23, 8 p.m., $35, Presbyterian Church of Chestnut Hill, 8885 Ger­man­town Ave.; Sun., Feb. 24, 3 p.m., free-will donation, Lang Music Build­ing, Swarthmore Col­lege, 500 College Ave., Swarthmore; 215-893-1999, piffaro.org, orchestra2001.org.