It's noon on Saturday and the leaders of the best big jazz band are finding it hard to rest their ears. Toshiko Akiyoshi and Lew Tabackin have endured a night of loud . . . LOUD . . . rock'n'roll through the wall between their Arlington motel room and the club next door. Now they're hunting up a late breadfast; at Lum's, middle-of-the-road rock drowns out any attempts at conversation, so they finally settle on O'carroll's, a bluegrass club whose daytime fare consists of piped-in country music. At least it's played low.

They are an odd couple. Akiyoshi is a diminutive Japanese woman who sprinkles her carefully constructed sentences with qualifiers like "so to speak" and whose phrasing on "musicians" sometimes sounds like "magicians," which is a fair appraisal of her 14-piece band. Her husband of 12 years, Lew Tabackin, could easily pass for a college professor. He is bearded, soft-spoken, reflective. In the last two years, the Akiyoshi-Tabackin Big Band has been voted tops not only in the United States, but in Europe and Japan as well. "But we can still use more jobs," Tabackin adds with a smile.

Born in Manchuria in 1929, Akiyoshi became a jazz pianist shortly after her famiy's return to Japan after World War II. By the age of 16, she was already a professional jazz pianist. Despite her success in Japan, she felt a need to prove herself in the land where jazz was born, so she moved to New York in 1957. After 10 years leading trios and quartets (including some with her first husband, saxophonist Charlie Mariano), Akiyoshi decided in 1967 to celebrate her decade with a Town Hall concert in New York. Among the musicians she hired, sound unheard, was Tabackin, doubling on tenor sax and flute.

"I thought, 'Who is this guy, he can't be any good, I never heard of him,'" she recalls. Before the first rehearsal, Akiyoshi ended up filling in on piano one night for Clark Terry's Big Band. At the Half-Note club, the rhythm section couldn't see the horn section, but the pianist liked what she heard from one particular play. It was Tabackin, who was supporting himself at the time by playing in the Doc Severinson band on the "tonight Show." Quartet dates soon followed, and in 1969 they were married.

When the Carson show moved to Los Angeles in 1973, the Tabackins went too. By this time, Akiyoshi had grown tired of the jazz world's rat race. She burned all her publicity material before the trip, and "I thought maybe it would be nice to be a housewife." Meanwhile Tabackin found a rehearsal hall (at the musicians' union) for only 50 cents an hour. Working with Akiyoshi's original compositions, Tabackin started the slow process of putting together a big band. That move kept Akiyoshi actively involved in the music business.

The band's initial five compositions had firsts been written for the Town Hall concert. Akiyoshi, still the only successfl female writer-arranger and big-band leader, felt some initial skepticism from musicians who not only had to deal with her as a woman, but had to "overcome the Oriental image of women as concubines or mistresses. Of course, at my age, I don't have that problem," she adds with a disarming laugh.

After some initial personnel changes, the band solidified and rehearsed for a year before venturing out commercialy. They still rehearse every Wednesday at the union hall ("it's up to $1 an hour now," Tabackin sighs), but getting that first gig was difficult. Despite the success in New York of the Thad Jones-Mel Lewis Big Band, Akiyoshi had trouble convincing club owners -- many of whom had hired her in smaller combo settings: "Here's this not-too-tall Japanese girl who wants to do a big band with all her own compositions," she recounts. "Emotionally, they couldn't see the music, or what kind of band it would be. They kept asking, 'Has it got a lot of melody?'"

The music apparently had enough of the right ingredients. The band has won numerous awards, traveled the world, recorded 10 albums. Akiyoshi is often compared to the late Duke Ellington, a comparison that, while flattering, amuses her. "I don't know what the Duke would think, but knowing him, he's probably happy, too." She views Ellington as the ultimate jazz composer and arranger, adding that another sign of his greatness is that today "trying to get a band that would stay together and grow up over 40 years would be impossible."

The band now tours about 17 weeks out of the year; when not on the road, most of the band members work in thelucrative Los Angeles studio market. Although Tabackin also goes out with small combos (he'll be at the One Step Down this fall), Akiyoshi prefers to stay at home, concentrating on filling out the band book (now containing 42 of her compositions) and, she admits, "watching too many awful television shows." "We need to maintain that separateness," Tabackin points out. "We always get lumped together. It's unhealthy; we are individuals."

And apparently getting to be well-known individuals, too. On a recent trip from Canada, the customs officers at the border were all fans. They never went through customs so quickly.