If you crossed the dune onto Brant Beach’s 68th Street beach Sunday and saw dozens of beachgoers staring at you, facing away from the water in their chairs, you were not losing it and you didn’t have anything on your face. You probably just stumbled onto a captivating set from the Black Ties, who took the summer stage at noon. With bright, sunny guitar riffs and relaxed, rolling percussion that seemed to move with the low tide, the band’s beach performance pulsed with the sound of summer.

The group played to a full beach crowd. Typical for a prime August weekend, the shoreline was packed with families…