Jane Siberry is the perfect singer to create new ways to hear Christmas. Sometimes sweet carols turn saccharine, all the old jingles are jingled out, and we need songs that are spiritual and surprising. That's what Siberry has sung since her first album in 1981 — not religious music, necessarily, but soulful.

Consider "Calling All Angels," her best-known song, which has appeared on two sound tracks as well as on her sixth album, When I Was a Boy (1993). Her voice soars up, swirls down, and drops to a whisper with unpredictable timing that makes you hang on each line. She travels through sketched scenes from loneliness to devotion to contemplation of mortality, until the cathartic chorus: "Walk me through this world / Don't leave me alone."

Ten years ago, the Toronto-born Siberry was edging close to commercial success, and the Windsor stations that were making local radio exciting played songs from When I Was a Boy. But her muse couldn't fit inside four-minute verse-chorus-verse patterns for long. (After all, her first hit in Canada, 1984's "Mimi on the Beach," was an eight-minute character sketch alternating sung lyrics and monologue.) So she went on to explore jazz, recorded songs she'd written as a teenager, and put out three live albums, a covers album, and a rarities collection.

It all culminated in last year's Love Is Everything: The Jane Siberry Anthology, which hits the clear highlights of her sprawling discography. Her voice — sometimes soaring, sometimes a tad husky, sometimes quirky, but always clear and unique — is almost all that unites the collection. But there's also a fragile beauty, and a sense of a spiritual depth, whether she's heartbroken, singing about nature and animals, or observing people and divining their secrets. She disregards songwriting convention as she follows one insight to the next, as if she's listening to other music, from above.

I won't try to locate her in a genre, like the poor librarian who'd crossed out "popular" and written in "folk Celtic" on the copy I borrowed of Hush (2000), a covers album that ranges across American and Celtic gospel and folk songbooks. The point is, when you find out that her new album is an interpretation of centuries-old Christmas-inspired hymns, you don't ask what's she doing jumping genres to sing Handel, Bach, and Mendelssohn, and you don't get hung up trying to understand the title, Shushan the Palace (Hymns of Earth). You just thrill to the way she explores the classical songs, including less-celebrated parts of Handel's Messiah, such as "I know that my redeemer liveth," or when she takes Charles Jennens's biblical eighteenth-century lyrics, reaches for the top of her range with the climactic line "the first fruits of them that sleep," and brings rebirth itself to life again.

Jane Siberry performs at the Ark on Tuesday, December 16, singing the Shushan songs and a sampling of her own best lyrics — including, her promotional material promises, "Calling All Angels."