She opened her mouth and the Who came out Petra Haden re-creates 'Sell Out,' note for note

Deeply weird ideas, cooked up late at night over the telephone, rarely transcend the supremely whimsical (or desperate or stoned) moment that spawned them. Usually, happily, the idea is forgotten by sunrise. Sometimes it's not, with outcomes that range from amusing to depressing. One exception is ''Petra Haden Sings: The Who Sell Out." The title is mind-bogglingly accurate; this is a homemade one-woman a capella re-creation of the Who's 1967 album. Haden, the daughter of jazz bassist Charlie Haden, sings every word, every drum roll, every guitar solo, and every mock commercial, note for note, front to back.

To the suggestion that her new album, released last month on Bar None Records, defies every unwritten rule governing the selection and treatment of cover songs, Haden replies: ''I would never have thought of doing this. It was Mike Watt's idea." Haden isn't passing the buck. She's giving credit where it's due. Punk-rock bassist Watt, a founder of the Minutemen, was a big fan of Haden's first a cappella project, 1996's ''Imaginaryland." Convinced that a singer eclectic and proficient enough to include renderings of music by Bach and Miranda Sex Garden on the same album would be up for the challenge, Watt brought Haden the concept and an eight-track cassette recorder with the ''The Who Sell Out" loaded onto track eight. She spent three years pressing rewind.

''I tried to re-create notes and parts as closely as possible," says Haden, on the phone from her home in Los Angeles. ''I listened over and over and over again. But I didn't want to sing like the Who the whole time. On the song 'Odorono,' I pretended I was Snow White. At the end of 'I Can See For Miles,' I added a weird dissonance, like I was from the Bulgarian Female Vocal Choir. I was sure no one but Mike Watt would hear it. I was not thinking about what Pete Townshend would think."

As it turns out, Townshend, the Who's legendary guitarist, has thought a lot about Haden's version of his band's third album, which broke the fledgling band in the United States. He describes his response in terms bordering on reverence.

''I was a little embarrassed to realize I was enjoying my own music so much, for in a way it was like hearing it for the first time," Townshend said in a lengthy e-mail interview. ''What Petra does with her voice, which is not so easy to do, is challenge the entire rock framework: the traditions, the processes, the decor, the accessories, the entirety of the established dynamics of traditional pop-rock. 'I Can See For Miles' is powerful not for the restrained electric guitars and suppressed and distant thundering drums of Keith Moon but for the torturously sustained vocal harmonies that John Entwistle added over my fairly conventional four-part. Petra is the first analyst who heard the vocal harmonies as they were written and reproduced them properly. When she does depart from the original music she does it purely to bring a little piece of herself -- and when she appears she is so very welcome. I felt like I'd received something better than a Grammy."

Haden, 33, was born four years after the ''The Who Sell Out" was released. A triplet, she grew up in a home that valued experimentalism over mainstream sounds. The Hadens owned no Who albums. When she was 8, Petra saw a young girl playing violin on the ''Captain Kangaroo" show and fell in love with the instrument. By the time she reached her teens Haden was an accomplished violinist -- she's contributed to albums by Beck, Green Day, and Luscious Jackson, and to many film soundtracks -- and had mastered trumpet, mandolin, and keyboards.

But it was her voice, with its extraordinary range, that stood out. Haden began articulating the sounds of instruments and creating intricate vocal arrangements of the Cocteau Twins, Pat Metheny, and Steve Reich. In 1992 she formed the band that dog with her sister Rachel, high school buddy Anna Waronker (daughter of the record producer and label executive Lenny Waronker), and drummer Tony Maxwell. That dog was together for seven years and three albums, during which time Haden became a busy support player on the LA indie scene and began a collaboration with the jazz guitarist and composer Bill Frisell; the duo's second album was released in January.

Mike Watt met Haden when she was hired to play violin and sing background vocals on his 1995 album ''Ball-Hog or Tugboat?" The two became close friends as well as frequent collaborators. Watt describes Haden as a virtuoso, and his overture to her -- to sing his favorite Who album -- as a dare.

''The first thing most people would say is 'Why should I?' She never did. Petra is that open," says Watt. ''She's also an amazing talent and sometimes it takes crude thugs like myself to point out a direction. She knew nothing of the Who and that's why I thought she could make it new for me."

To hear clips from ''Petra Haden Sings: The Who Sell Out," please go to Boston.com/ae/music.

Haden said yes for two reasons: She likes reinventing things and she likes Mike Watt. Recorded piecemeal in the bedroom, the kitchen, and at a friend's house in the desert, these tracks will never be described as state of the art. Before Haden's cousin had at it with Pro Tools, the home-computer software that simulates a recording studio, you could hear the crinkling of lyric sheets Haden held while she sang. It was meant as a gift for a friend, and that's what it sounds like: a homemade treasure -- lovingly crafted, utterly unpretentious, and thoroughly original. Just the sort of thing to make a rock god rethink his legacy.

''A lot of our most subtle work was buried under gimmicks, tricks, noise, and ego," says Townshend. ''That's perfectly OK. But Petra's lack of preconceptions have made it possible for her to avoid the notion that she ever, ever had to raise her voice on this project. Any subtlety lost in the Who's pop-art approach has been restored."

Joan Anderman can be reached at anderman@globe.com