"Whether it's in my music or my clothes," says Linda Ronstadt, 33, "I've always liked to put the opposite thing in, something that at first might not seem like it belongs."

A fair self-assessment, judging from the cover of her new album, Mad Love, with its grainy New Wave graphics depicting a strikingly short-haired siren caught in the midst of a confidential phone call, as well as from the LP's contents. Ronstadt has all but abandoned her country-rock conventions in favor of a controversial, raw rock tack signified by her covering no less than three Elvis Costello songs ("Girls Talk," "Party Girl," "Talking in the Dark") and three compositions by Mark Goldenberg of the L.A.-based Cretones.

There is a new Linda Ronstadt to look at and listen to, but she is rather quick to confess that many of the elements are old, borrowed - and blue. "I like to take his songs and switch the gender around, because his gender assignments are very flexible," she says of the Elvis Costello material, specifically "Girls Talk."

"You remember high-school girls' talk," she says. "It's always gossipy and it's scandalous and it's naughty, and there's always some real hard kernel of truth in it. Girl's talk is something you can use to defend yourself, and you can use it to attack with - a flexible kind of weapon. I love that first line in the song: 'There are some things you can't cover up with lipstick and powder.'"

It seems Linda chooses her look the same way she selects her songs, paying careful attention to the prevailing vogue and adapting it to suit her own perspective. "I try to stay away from things that are too trendy, 'cause they're too hard to adapt. It would be silly for me to dye my hair pink and start pogoing," she explains. "It wouldn't be part of my experience. But it isn't any problem to draw from people like Buddy Holly and rockabilly and Mersey beat stuff - and those are the elements that we've incorporated. The music [on Mad Love] re-combines various classical themes, and I like to look at fashion the same way. A Levi jacket is pretty classic, and so is Victorian underwear. And for some reason, putting them together makes perfect sense to me."

Over the years, Ronstadt's sense of style has often been influenced, if not dictated, by environment, happenstance and necessity.

"I hate to shop," she confesses. "Instead fo shopping, I just go into the top of my closet and drag out something old and figure out some new way to do it up. Basically, I haven't bought any new clothes for about three years.

"The Levi jacket, the one that says SIN CITY on it - I've had that jacket forever. The overalls that I wore around the time of my first album - I still wear them all the time but with different things. On one tour, I lost so much weight that none of my clothes fit, so I just kept borrowing shirts from the guys in the band; I'd reserve their shirts a couple of days in advance. Then I started buying my clothes in little boys' department 'cause they were small. That's where I got my Cub Scout suit.

"Now this new look is not really a change, it's just a different facet of my personality. As each new facet is exposed, the public tends to think the 'slide' is being changed. It's not; it's just being rotated." Ronstadt describes her hyper-short hairstyle as half an ending and half a beginning. "A different hairdo makes you feel different. I remember there were six weeks when I cut my hair every week. And everytime I changed my looks drastically, it changed my attitude somehow." But, she says, "I'm tired of my short hair now; I just want it to grow out.

"Music is always a couple of steps ahead of high fashion," she rules. "It used to be movies that dictated high fashion, but pop music too over a long time ago - around the Fifties. Fashions reflect cultural change.

"The avant-garde perceives changes in the working class that maybe the working class hasn't perceived on a conscious level. Then, the avant-garde picks it up and begins to wear it as an affectation. It's broadcasted back through the media to the working class and they adopt it on a second-generational level. So the avant-garde reflects the working class, and the working class relects the avant-garde."

Lately there have been several other changes for Ronstadt, among them the rehearsal of a roadworthy new band consisting of rhythm guitarist Danny Kortchmar (who has just released a solo LP, Innuendo, on Elektra/Asylum), Dan Dugmore on lead guitar, Russ Kunkel on drums, ex-Little Feat member Bill Payne on keyboards and Bob Glaub on bass. After a month-long (late March to mid-April) tour of mostly the Midwest and East Coast, Linda is scheduled to make her stage debut - playing the female lead, Mabelle, in Joseph Papp's production of Gilbert and Sullivan's The Pirates of Penzance - this August at the Delacorte Theater in New York's Central Park.

On the rock front, Ronstadt feels, "Rock & roll is fun and the music is coming back. There was an enormous amount of narcissism and self-seriousness in the last ten years, which I think had to be there. And then it got detached, so it became like Devo, sort of convoluted and inward, with a real mechanical approach. Then, in order to stop being that, it all has to be kind of joyous.

"It's almost a little too predictable. Whatever the trend is, the almost exact opposite is going to happen. When there was a trend to naturalness, then there was a trend toward things totally artificial. If everybody's eating granola this year, then everybody's going to be eating syntho-food next year."

Reviewing the shifting elements of her own styles of music and dress, Ronstadt concludes, "I don't think there was a conscious attempt to change. Things change imperceptibly of their own accord - in music, personalties, etc. And if you're involved in music or any occupation that exerts any influence over the culture, then your response to that has an impact - it's fifty percent influencing and fifty percent being influenced.

"I went around to every club there was and I saw all the acts; I just digested it. I sat and talked to [producer] Peter Asher in his manager's hat about what I'd heard and what I wanted to do. He always encourages me to try to find another producer, but I honestly feel he's right for me. I think it shows a lot more courage and a lot more strength to try to evolve with the same team."

Speaking of constants, what does Ronstadt plan to pull out of the top of her closet to wear on her tour?

Boy, I sure don't know," she says nervously. "I can't think of anything."