Ring out, wild bells.

In the winter dark of city sounds, a carillon cheerily pierces the air. The unexpectedness of tunes settling over Rittenhouse Square is one of the park's great pleasures. Listen, look up - these sounds are pockmarked with history. They come from the Church of the Holy Trinity, 25 tuned bells from 1883, including the big one, the 3,500-pound

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. In a neat bit of tintinnabulation tabulation, Lisa Lonie, the church's carillonneur, says the instrument is the smallest among the 15 in the Delaware Valley. Mostly it is played automatically - melodies for Advent in the next few weeks, at noon, 3 and 6 p.m. But on Christmas Eve you might hear a carol of special local resonance. The text of "O Little Town of Bethlehem" was written by Phillips Brooks, the church's rector, after he visited that little town in 1865, with music added by Lewis Redner, organist at the church for a two-decade stretch long ago.

- Peter Dobrin

Peals to pedals. If you time it right Friday, you can walk from 6 o'clock peals in Rittenhouse Square to the vibrating air at Macy's, where, at 7 p.m., Peter Richard Conte stirs the Wanamaker Organ to life with flugelhornist Andrew Ennis in a free holiday concert. - P.D.

Talented two. Violinist Eunice Kim and pianist Andrew Hsu are among the more enterprising artists coming out of the Curtis Institute. In her Astral Artists recital at 3 p.m. Sunday at the Trinity Center for Urban Life, Kim nods to the usual career-making showpieces with the Sarasate Carmen Fantasy she played last summer with the Philadelphia Orchestra at the Mann Center. But she also premieres the Violin Sonata written for her by her composer/pianist Andrew Hsu. Much of the rest is atypical recital fare, including tango-based Astor Piazzolla. The pair repeats Hsu's sonata at 8 p.m. Wednesday at Field Concert Hall in a free concert of Curtis composers. Astral info: 215-735-6999 or www.astralartists.org. Curtis: 215-893-7902 or www.curtis.edu. - David Patrick Stearns

Turning the key. Terry Riley's history-changing, ever-modern In C turns 50 this year, and an in-the-round presentation Thursday at the Kimmel Center's SEI Innovation Studio is bent on showing what a sea change it marked. Performed by the Aizuri Quartet, eighth blackbird, and Curtis' 20/21 Ensemble, the proto-minimalist, back-to-tonality piece will be accompanied by graphics, photos, and even notation from Riley's score, projected onto the walls to recapture the mid-1960s in immersive lounge style. The audience is encouraged to dress in the spirit of the times. Two shows: 6 and 9 p.m. Tickets: $10. Information: 215-893-1999 or wwww.kimmelcenter.org. - D.P.S.