Inside you wander through a pool room, past a sumptuous bathroom, up a flight of stairs with a statue of a saint at the top - and into the main sitting room, which also serves as a studio for Lanois's artist of the moment. This time, it is Emmylou Harris.
In a light summer dress she completes the musical dream. Listening for the first time to a complete playback of her new album, she sits in a chair that could only seem normal in the Lanois household - throne-shaped, with bronze figurines of barking dogs at the end of each arm.
That evening, when we go out for dinner, she refers briefly to the break- up of her three marriages and says elliptically: "My marriage break-ups are a source of sadness, and everything you experience comes out one way or another. There is a great melancholy. Don't you think that most people are sad?"
She looks serene. She shuts her eyes and sways gently, her fingers continually sweeping through the mane of long, silver-grey hair that flows over her shoulders.
The grey hair is genetic, and she defiantly refuses to dye it. But then she has a disregard for fashion, which is why she chose not to make her new album, The Wrecking Ball, in her home town of Nashville but in the sodden humidity of New Orleans, with the man who produces U2. He may shock her purist country following with a resonant studio sound which he describes as "rust", but which Harris says ends up as "a kind of Phil Spector sound... we weren't going for it, it just happened."
It would have been fascinating to see how it happened. An indication of the respect in which Emmylou Harris is held is the way stars will come at the drop of a hat to record with her. The Wrecking Ball's title track is a gently hypnotic and hidden classic off Neil Young's Freedom album, and Young flew to New Orleans to sing backing vocal on Harris's mesmerising. Neil and Mrs Young danced to the result on the Lanois carpet before flying home.
The other outstanding track is "Harlan", a melancholy lament by Anna McGarrigle. Harris may actually write very few songs, but she can instill a haunting sadness into the songs of others.
It was a quality first noted by her mentor, the late Gram Parsons, the sometime Byrd and Flying Burrito Brother, now legendary pioneer of the fusion of country and rock. Harris's relationship with Parsons epitomises the air of enigma and mystery that surrounds her.
Born in Birmingham, Alabama, in 1947, the daughter of a military officer, she was brought up on a series of marine bases. From an early age she wanted to be a folk singer. At high school in 1963 she wrote to Pete Seeger for advice. "He wrote back and told me to read the books of Woody Guthrie, and very sweetly added, `Life will catch up with you'. I had no credentials. I hadn't suffered." Three broken marriages, various snubs by the world of country music and the still-felt shock of the death of her mentor have changed that.
By 19, Emmylou had dropped out, joined a hippie colony of musicians in Virginia, and moved to New York - waitressing, folk singing, getting married and having a baby. It was when she was singing in a bar that a Flying Burrito Brother spotted her.
Harris speaks rhapsodically about Parsons, yet claims there was no affair. "He gave me a centre, he gave me style. He took the raw talent I had and forged it into something. He gave me a love of country music.
"People always ask if we had an affair. I keep saying no and no one believes me." Instead, we must believe that in the company of one of the most charismatic figures of the age, the strikingly beautiful young woman spent her time crocheting. "I was making an Afghan for my daughter. I found it very therapeutic."
Twenty-four albums and 20 years later, she has experimented more than the country faithful are prepared to tolerate. It has provoked a bitterness in her about today's increasingly glam country scene.
``It's all become so youth-oriented in the States. It's difficult for me to talk about. I don't know what country is any more.
"Garth Brooks... well it's a different music. It's kind of like borrowing from the old style, which is good. But I tend to like music that is more challenging than just playing a little harder."
Harris has never gone public on the reasons for her marriage bust-ups. Her last two husbands were both in the music industry, the Canadian Brian Ahern produced most of her classic albums, and the British singer/ songwriter Paul Kennerley also collaborated with her.
The one-time hippie is now the over protective parent that walks her 5ft 10, 15-year-old daughter to school in Nashville every morning, partly out of parental paranoia about American city life and partly because of regrets that she spent too little time with her older daughter, now 24.
But her real motives are never easy to discern. How, for instance, does one reconcile her protestations that she and Parsons never touched with the fact that in 1985 she co-wrote the concept album The Ballad of Sally Rose, a country opera about a young woman singer who falls in love with her mentor?
"Yes, The Ballad of Sally Rose was definitely based on my relationship with Gram." Is this about to be a revelation that will go into the annals of musical history?
"It was based on knowing him, on how much I cared for him. I did love Gram very much. He was very important to me. He changed my life."
It is a typical Emmylou Harris answer. It seems to go so far, yet it leaves her mystery suitably, and no doubt deliberately, intact.
n `The Wrecking Ball' is out on Grapevine RecordsReuse content