At the opening concert of the three-part festival series “Stop Over 4,” New York-based saxophonist Ingrid Laubrock, curator of the first day of the festival, has put together three sets with renowned musicians from the international jazz and improv scene: including “Ecstatic Looms” for three string players (featuring electronica-savvy violinist Jessie Marino, among others), a trio concert by vibraphonist Yuhan Su, and a duo performance by LGBTQ* activist Fred Moten with double bassist Brandon López. Ingrid Laubrock will give a concert introduction at 6:15 p.m.