Ben Wendel and Dan Tepfer at the Blue Whale At first glance, a rhythm section-free duo outing between a piano and saxophone could be considered a challenging assignment for some jazz listeners. Not so with Kneebody saxophonist Ben Wendel and pianist Dan Tepfer, who has been tapped as a rising star after collaborations with Lee Konitz and an inspired album-long take on Bach's "Goldberg Variations." Based on a show last year at this same venue, plenty of sparks will fly when these two forces meet, as heard on a new recording, "Small Constructions." The Blue Whale. 123 Astronaut E S Onizuka St. Suite 301, Fri., 9 p.m. $15. http://www.bluewhalemusic.com.