Crescendo’s opening concert program of its 15th season offers audience members a musical glimpse of the rarely-heard, exquisite repertoire written for theorbo and harpsichord. Performances are 4 p.m., Sept. 7 at Saint James Place, 352 Main St, Great Barrington, and 4 p.m., Sept. 8 at Trinity Church, 484 Lime Rock Rd, Lakeville.

Not commonly seen on U.S. concert stages, theorbo, or chitarrone, is the largest member of the lute family of instruments that was developed around the end of the 16th century. It was used primarily to accompany small vocal and instrumental chamber ensembles as well as solo vocal music. Its role as a solo instrument was an afterthought, but innovators on theorbo left behind a small repertoire of high quality.