Not many could be named connoisseurs of melody — in composition and in song. This is how Big Dipper designates the Guided by Voices frontman on a track lovingly titled “Robert Pollard,” a strange gem from their first record in more than 20 years. They answer the enigmas behind writing tunes that thrive — with “a rising chorus that opens wide,” as one must “bend in perfect rhymes” — demonstrating through the lyrics just so. But Big Dipper always had the melodic upper hand. “Pitbull Cruiser” recalls their debut, Heavens, channeling the familiar funk rhythm of Talking Heads. Since guitarist Gary Waleik spent time with Pollard in the science-driven project Mars Classroom, shards of that bond remain in “Hurricane Bill” and “Sarah and Monica.” Demand for a “New Machine” then overtakes like a rock ’n’ roll transmission from space.