The term “trip-hop” makes perfect sense the moment anyone hears the woozy one-two hit of Portishead’s 1994 singles “Glory Box” and “Sour Times.” Combining Beth Gibbons’ emotive, mournful vocals with guitarist Adrian Utley’s spidery work and producer/multi-instrumentalist Geoff Barrow’s hip-hop-style beats and flickering vintage samples, the Bristol, England trio seemed to arrive fully formed. Their 1994 debut Dummy won the Mercury Prize and, more recently, ranked on Apple Music’s 100 Best Albums list, still maintaining every ounce of its smoky allure. Portishead’s self-titled 1997 follow-up went a step further by largely employing self-created samples, along with spooky horns on the reverbed “All Mine” and Barrow’s drowsy record scratching on “Only You.” A full decade intervened before 2008’s Third, heralded by the juddering distortion of “Machine Gun” and the unlikely collision of folk and electronics on “The Rip.” Yet, those would-be outliers wound up fitting right into the act’s evolving tapestry of sounds and influences.