‘Tis the season to begin thinking about finding and supporting some excellent holiday music, which we’ll do in this edition of the Saturday Soundtrack. When you tire of the endless, dreary Christmas muzak, I suggest you set up a winter solstice playlist or take in a concert by Robin Bullock to alleviate your pain. For years I’ve been a regular at Bullock’s Celtic Holiday Concert sponsored by the Institute of Musical Traditions, and I’ll be there again next week for the 2019 performance. Set for Monday, December 9th at St. Mark’s in Rockville, the concert also includes, besides Bullock, the world-class folk instrumentalist Ken Kolodner on fiddle and hammered dulcimer, along with U.S. National Scottish Fiddle Champion Elke Baker. Bullock is a master of the acoustic guitar, cittern, and mandolin, where he blends “…the ancient melodies of the Celtic lands, their vigorous American descendants, and the masterworks of the Baroque and Renaissance eras into one powerful musical vision. The 17th-century harp tunes of legendary Irish bard Turlough O’Carolan, the spirited jigs and reels of rural …