The Underground Music Showcase assembled one of the best lineups for the Red Bull Sound Select affair last Saturday at the Bluebird Theater. Headliners Wild Nothing brought their hazy brand of shoegazy dream pop. Vocalist Jack Tatum appears only to get starting with his dreamy lead sensibilities on the latest album, “Life of Pause.” The Virginian act have improved with their live set since their early days of “Gemini” with a stronger stage presence rallying around Tatum and his guitar noodling. The intense focus by the quintet made for a heavy ambiance that didn’t weigh down the Bluebird crowd. However, Real Estate/Girls member Matt Kallman held it all together with his masterful key playing.