Rosalía made one of the year’s most demanding pop albums. Listen closely.

Let’s try to keep calm, because, for all of its ambition and grandeur, this new Rosalía album, “Lux,” demands a sharpened mind more than a blown one. It’s an opaquely themed, scrupulously produced concept record in which the Spanish pop auteur sings about a handful of saints and martyrs in more than a dozen languages, backed by the unmitigated power of the London Symphony Orchestra — a stacking of lavish gestures that Rosalía hopes might help elongate our diminished online attention spans.