As fans are well aware, Delerium began their career recording strictly instrumental music in a highly atmospheric, soundscape vein.

That musical penchant hasn't changed, but over the years the duo has utilized ever more vocalists to further enhance its sound, culminating in Nuages du Monde.

This set boasts seven different female vocalists across its 11 tracks, and a mere two instrumentals.

Opera star Isabel Baryakdarian powerfully opens the album with the evocative "Angelicus," her soaring vocals and the number's textured atmospheres a revelation that echoes the song's religious underpinnings.

Her "Lumenis," later in the set, is an equal standout, here her delivery pinioned between East and West, further accentuating Nuages du Monde's most haunting track.

The equally feted Punjabi singer Kiran Arwuhalia is Baryakdarian's equal, her wondrously keening vocals across "Indoctrination" echoing around the swooping synth.

These two performers are of such quality that their light virtually outshines all the rest.

Still, Katharine Blake's bubbling and effervescent delivery is exquisitely showcased on "Extollere," and is far removed from the blurry, breathy vocals she offers up on the much weaker "Sister Sojourn Ghost." In contrast, Kristy Thirsk's pretty-as-a-peach vocals work a charm on "Self-Saboteur," a song that also boasts the album's catchiest chorus.

"The Way You Want It to Be" is even more pop-flecked, while Jaël's "Lost and Found" encompasses flickers of new wave, rock, and pop, one of the set's most musically intriguing tracks.

Filled with rich atmospheres and myriad moods, ranging from shadowed to bright, Nuages du Monde embraces a surprising variety of musical styles that shimmer and shift with great suppleness throughout the set.

However, as splendid as the music is, the occasionally overly forceful rhythms at times get in their way, not so much counterpointing the moods as undoing them -- the only thing marring an otherwise flawless album.