Jane Siberry is being pampered on a side street in old San Francisco, and I'm immediately jealous of at least part of that.

The city itself is a miracle of visual and materialistic delights, from the grotty row houses where Hunter S. Thompson used to stay up all night writing to anesthetic Japantown, where the best imported incense and shaving cream in the world can be bought for possibly too much money. And you should see Amoeba Records, the size of a grocery store, and just as full of delicious possibility.

But Siberry, best known for her long-ago, underground hit Mimi on the Beach, is taking care of more important things those few miles from Alcatraz, namely herself.

She's playing Spruce Grove's Horizon Stage Tuesday night, by the way, in what at first glance looks like a Christmas concert. Don't be fooled. Featuring rather traditional covers of classical music, her new album Shushan the Palace (Hymns of the Earth) represents a further distancing between Siberry and her pop career. But first, back to the nail job.

"I've had a terrible morning," she says in her shiny little Christmas ornament voice. "So I thought I'd talk to Fish on the phone while I had my nails done."

It's neat to picture her in that chair, like a Norman Rockwell painting called The Manicurist and the Artist. Everything Siberry does seems to have a slightly ironic flavour, as if her life is just a clever art show. She is quirky, and some would certainly call her precious. But, like David Byrne, those impressions come from the fact that she's excitedly connected to things that other people don't even really notice, be it grouper fish, the swearing during hockey games or even pretty girls lying around in the sand.

"I'm very interested in systems," she explains. "I'm known as a bit of a pest around older people, once I find out they're experts in their field. I like to dig around in their memory because they can give you really precise information. Some of them are war vets and I might want to know what it's like, what the daily routine would be, or how a submarine works."

Siberry's life and career are a bit like a submarine, actually. She is a self-contained company and left the port of the major record labels to rise and submerge at her own pace on the open sea. As time has passed, she's moved from mainstream pop, where she never really was in the first place, to what some would call loftier planes, including doing a jazz album, a high-concept trilogy of records and this latest album of sparkly classical covers, full of strings and hope.

"It was supposed to be a Christmas record," she says, dropping her voice down a few notes at the end, "but I got bored with that idea. I put a notice out to my e-mail list in March for suggestions and I got so much high quality information from everybody I spent months going through it all and testing it. So many of them are real music lovers and aficionados, and so that sort of led me out of the Christmas repertoire. The songs started to organize themselves and some of them just didn't want to be on the album."

Opening with a lavish cover of Handel's How Beautiful are the Feet, Siberry visits a couple of more songs from Messiah, moving into other classics, as if she's been a choral singer all along. It wasn't like that.

"It was interesting to try and harmonize with a lot of them," she says, continuing to personify the numbers. "Some of them frustrated me and I would shout at the songs. I learned to listen differently, to really break down the sound and take it all apart before I put in the vocal arrangements."

The first thing that struck me when I listened to the album is how much religion was floating about, a surprising move from Jane's earlier days of what amounted to humanistic spiritualism.

"I had the normal Anglican Presbyterian upbringing, but none of us really liked church and Sunday school, so I stopped going as soon as I could get away with it. But then the siblings in my family, we all started using the word 'God' again, and even saying grace. It's a subtle thing. With the songs, I couldn't stomach some of the dogma. At my live shows I say to people, 'Try to squint with your ears and hear the beauty.' I changed some of the lyrics when they got to be too much."

We talk for a long while, but eventually the manicure is making things difficult.

"It's called multi-tasking," she laughs. "That's my life now. I seem to be doing a lot of things besides music. If it's not hiring people to do Web programming, it's contractual things that I need to be involved in. My father passed away last year and I finally let myself be more irresponsible. After this tour, I'm gonna disappear for a while.

"Not to do music, but just to take a break and wander around."