In 1974, a Northwestern professor had the idea of pairing the choir at Evanston’s St. Luke’s Episcopal Church with instrumentalists from the Chicago Symphony Orchestra and the Lyric Opera to showcase the music of Johann Sebastian Bach. Forty years later, Bach Week is still going strong. One of the highlights every year is the Candlelight Concert. This year’s concert takes place Friday night at Nichols Concert Hall in Evanston. The man in the spotlight-or candlelight-is homegrown classical guitar virtuoso Adam Levin. He joins us in studio to give a taste of his artistry.