Mogwai are by now almost elder statesmen of dramatized, soft-and-loud, elegiac-and-distortion-heavy instrumental rock. They have increasingly focused on soundtracks and now we have “Kin,” backgrounding the recently released science fiction movie. A soundtrack is by definition music of muted impact but Mogwai’s modus operandi is highly congruent with such works, and Kin is a fine, atmospheric album that walks no new ground but soothes and bathes. Guitar squalls follow light piano motifs follow spooky synths follow thundering bass follow drifting feedback. The longer the track, the better according to me, so the highlights include the stately, ratcheting-up title track, the piano-led “Guns Down,” and the superb synthy rave-up “Donuts.” One for the study or late-night headphones.