Grey Oceans' unfortunate cover art is a reminder of everything that can be seen as irritating aboutCocoRosie -- a pity, because there is a lot of beauty on this album. Sierra and Bianca Casady's songwriting and approach matured in the three years between these songs and The Adventures of Ghosthorse and Stillborn; even though it still sounds like Ouija boards and wax cylinders are vital pieces of equipment for them, Grey Oceans has a more expansive and polished sound than any of the sisters’ previous albums, and they don’t try to fill each song to the brim with sonic doodles. “Trinity’s Crying” begins the album by proving that CocoRosie sound as witchy as ever with its mix of odd samples and acoustic instruments, but as its coolly hypnotic vibe unfolds, it’s clear that it was made in a more professional setting than, say, a Paris apartment. “R.I.P. Burn Face” also shows how far the duo have come since Ghosthorse and Stillborn, fusing warbling synths, wandering beats, and a delicate melody into a song that is equally sophisticated and ethereal. Grey Oceans' arrangements and instrumentation are also among CocoRosie's finest. “Lemonade,” for example, captures summer’s idyllic beauty by melding a melody that sounds like it could be from a long-lost Broadway musical with trip-hop-tinged beats, electro synths, and brass. Not all of the album’s daring combinations work as well, though -- for every inspired turn like “Fairy Paradise,” which fashions static into a ghostly but persistent beat, there’s a song like “The Moon Asked the Crow,” which, with its mix of gamelan, classical piano, hip-hop beats, and a train whistle, puts too many ideas into play at once. More importantly, the whimsy that sounded charming on the Casadys’ previous albums ends up holding them back here. “Hopscotch”'s switch from rinky-dink pianos to jungle-inspired breakbeats is daring but jarring, and the keening, Joanna Newsom/Björk quality to the sisters’ vocals sounds grating. Meanwhile, “Here I Come”'s pitch-shifted recitation of phrases like “A hollycaust/A pussy wussy willow” is plain off-putting. At their best, theCasady sisters’ music borrows from folk, electronic, pop, world, jazz, and whatever else suits their fancies with innovative boldness. Not all of Grey Oceans' experiments and changes succeed, but enough of them do to suggest that CocoRosie can gain a wider audience without sacrificing their essence. While they have many good ideas, sometimes they have too many good ideas at once and end up gilding the lily (or putting a blue fake fur mustache on it, as the case may be).