In pondering how to blend his own musical instrument with Cleo Laine's, John Dankworth muses, "The sax and the female voice start out a long way from each other. It's the sort of thing that would be hard to do unless we were living together and could try it out any hour of the day or night." Fortunately, for the world of jazz, composer-saxophonist-clarinetist Dankworth and songstress Laine have been living together and trying it out for 16 years as man and wife.

John is Britain's preeminent jazz artist and a notable composer of movie scores (Darling, Morgan, The Servant). Cleo is the Holiday-Garland-cum-Lenya of Britain, but until last year was appreciated in the States only by critics, cultists and other musicians. Reviewer Leonard Feather has called her nothing less than "the greatest all-around singer in the world." Another admirer, Benny Goodman, asked her and John to accompany him in a television special now in national syndication. Though she had visited the U.S. for a few earlier concerts, Cleo had "always been nervous of trying my luck" here. But this spring she is touring from Oakland to Philadelphia and, though diffident about promotion, is playing shyly along with appearances on the Today, Tonight and Merv Griffin talk shows. Finally, her third American record album has just hit the stores.

The Dankworths—both now 46—have been together since John offered Cleo six pounds a week to sing with his jazz band in 1952. "Make it seven," countered Cleo, and it was a deal. Trained at London's Royal Academy of Music, John already had established himself while Cleo, the daughter of a West Indian migrant and his English wife, was still struggling. She had been a hairdresser, milliner, pawnshop clerk, librarian, cobbler and already married and divorced by the time she was 18. Her early years with Dankworth's group helped Cleo enlarge her incredible vocal range—four octaves to a high "super F." Periodically she left the band and made a wider reputation, singing everything from leider to Dankworth's offbeat settings of Shakespeare sonnets to Kurt Weill, acting in A Midsummer Night's Dream, and even portraying Hedda Gabler.

"We're used to playing career leapfrog," says John. Cleo chimes in, "It's bad to be in each other's pocket all the time," though she thinks it never hurts to be at each other's throat. "She's a sworn supporter of rowing in a marriage," reports John. Cleo says, "Our fights are a safety valve. If you bottle it all up, you walk out or commit suicide." The battle is joined right from the ordering of their day. John is an early riser—sometimes before night bird Cleo has even gone to bed. Many of their contrapuntal rows take place around two grand pianos in the antique-cluttered living room of their converted Old Rectory home, which is spread over 17 Buckinghamshire acres. They have 10 bedrooms, a stable and a 200-seat recital hall for their annual charity music festival and student workshops whose range from Palestrina to pop is characteristic.

If John is the conductor, Cleo is the prima donna. "I recognize his artistic superiority," she says, "but quite often, my intuition is proven right. John is ambitious for me. He's the dynamo; otherwise, I'd just sit. He has no need to be jealous of my achievements because he's done so much himself." According to John, "Cleo can go overboard in relying on pop and hit-parade sources. She is so much an actress that she would overdo the histrionics if there were not a good musician to keep her in hand. We strike a balance which is just about right. Whatever is exceptional about Cleo's repertoire—from Aznavour and Bach to Carole King and James Taylor—is due to the battling."

At home with their children Alec, 13, and Jacqueline, 11, the Dankworths muddle through in casual, unpampered comfort. Guests at meal time are in danger of being invited into the kitchen for some meatballs and a hard-boiled egg. "I tried hard to be the little woman and a good mother," says Cleo, "but it really wasn't my role at all. After a while, I'd start bullying and shouting at the children, and they'd urge me to get back to work." John will make the bed when Cleo's not up to it and "household maintenance" is described in Who's Who as one of his favorite recreations.

"We recognize," says Cleo, "that we are quite different and opposing personalities, and we know how to cope with it. If you reach the point of explosion, you duck." She added, with a mischievous smile, "When you put it all down and start analyzing it, we have nothing in common whatsoever"—and then she burst into laughter. John just beamed.