Imagine an orchestra of pitched percussion instruments. The exotic rhythms are created with a mix of gongs, metallophones, zithers, xylophones and drums. The sound evokes the rich culture of Indonesia, where this type of ensemble is integral to the court and sacred music of the nation. At the same time, the sights are a feast for the eyes, as the performers don brightly colored robes, flowers and head wraps. That’s the experience the CMA is presenting when it brings Evan Ziporyn to town on Friday, January 8, along with his 30-member Gamelan Galak Tika.