Black Lines is another rewarding chapter in Mayday Parade's move into grungy, hard rock heft. Let's be clear about this: The Florida act still are and always will be largely rooted in emo and post-hardcore, especially Derek Sanders' impassioned howls. But there's no denying that "One of Them Will Destroy the Other," "Let's Be Honest" and "Hollow" all seethe with an energy that totally recalls old-school Sub Pop (think Seaweed crossed with early Nirvana). Even when Mayday Parade do get introspective ("Letting Go," "Narrow"), the music remains very physical and tactile. That's cool.