Why does Lake Trout call their music ''post''-rock? There's little that's as comfortingly retro as the lush dreamscapes on Not Them You. The quintet has abandoned earlier flirtations with hip-hop and electronica for angular harmonies, oblique lyrics, and guitar-keyboard-flute arrangements that evoke ancient groups like Love or Traffic. (There's even an oddly lovely cover of the Stones' ''Street Fighting Man.'') Some Radiohead-esque echoes aside, this disc leaves the present behind.