With nearly a quarter century of practice under its belt, Maryland band Clutch has perfected its brand of rocking. The men who formed the group are still in the group, which blends Southern stoner-rock vibes with wah-wah guitar solos and plodding grooves. Clutch just released an anvil-heavy return to form, "Earth Rocker," and fans will hear plenty of the new material Sunday night at The Knit. If you're going, show up early enough to be floored by opening act Orange Goblin. The slightly more metallic British band is no newcomer; it was formed in 1995 and, like Clutch, knows its bludgeoning craft all too well.