Before they pushed their songs into the realm of endless drone, the Melvins created vignettes of brutality with Ozma, their second LP. Among the album’s 16 tracks, only two surpass the three-minute mark, and many clock in at less than two minutes. It’s an unusual but refreshing approach to heavy rock music, which usually demands plenty of space to deliver its impact. The short songs on Ozma only seem to gain power from their limited duration. Each song turns into a micro-study of the riff — demolition in miniature. While the band won respect for its relentless low-tuned, distorted riffs, Ozma proves that the Melvins’ greatest strength is their rhythmic ingenuity. Where most bands settle into a riff with total complacency, the Melvins always take an unexpected turn. As soon as they have you settled, they’ll jerk you in the opposite direction. While it is impossible to ignore the exhaust hit created by guitarist Buzz Osbourne and bassist Lori Black, Ozma belongs to drummer Dale Crover. Like a mutant version of John Bonham, his brickbat rhythms explode like land mines throughout these performances.