“What if the way I stay is always changing?” Emma Ayzenberg asks at the opening of “count the dreams,” the closing track of her newest four-track EP. This acceptance of both our constancy and our mutability sit at the heart of iron mountain—the EP’s title a nod to the English translation of her last name, Ayzenberg. The result is a collection of songs that are at once self-assured and undefended, giving voice to collective and personal pain that a less-ripened heart might find unspeakable. iron...