Sigur Ros ‘Med Sud…’: Aidin Vaziri | If you have spent the past decade lying awake wondering what Sigur Rós front man Jon Por Birgisson is singing about in his famously made-up language, here’s some good news: The Icelandic quartet’s fifth album includes its first song ever sung in English. Not that you can make a word out through that glass-shattering falsetto. Like the other 92 percent of “Med Sud,” what really makes the music float is a woozy concoction of sad piano melodies, thumping rhythms and ambient noise. Produced by Flood (U2, Depeche Mode) and recorded at various ports around the world, it’s supposed to be both looser and more polished than anything the band has done before. But to our ears it still sounds like a couple of whales playing a game of hide the bone.