[youtube]http://www.youtube.com/watch?v=x0d1HilfLxA[/youtube] British guitar hero Robin Trower got his start in Procol Harum (“Whiter Shade of Pale”), but his Hendrix-esque style wasn’t part of the band’s sound. Trower’s at the House of Blues tonight; here he is playing the title cut from his best-known album, 1974’s Bridge of Sighs.