The first time Keith Brion assumed his alter ego as John Philip Sousa, he knew he had found his niche. "When we gave our first Sousa program at Yale, it all sprang to life again, like someone had rubbed a genie's lamp," he said. "And when I conduct my programs now I feel like Sousa, I have more fun than the audience."

Brion will be in Utah this weekend to lead the Utah Symphony in "Sousa Salute" - a fitting program for the Days of '47 weekend. Concerts will be in Symphony Hall at 8 p.m. Friday, at Deer Valley at 7:30 p.m. Saturday, and at 4 p.m. Sunday on the Snowbird Pavilion.Incidentally, Sousa was well-known to Salt Lake audiences of his time, having appeared here on his very first national tour - on April 7, 1892 - in the Salt Lake Theater. "He was there at least six times, maybe more," said Brion in a telephone interview. "He last appeared in 1927, in the Tabernacle."

Brion also simulates Sousa's style of programming. "He never listed his marches, but mixed them in as rapid-fire encores, among a program of light classics, novelties and virtuoso instrumental and vocal solos. Someone would just stand up and hold up a card saying which march, so his programs were twice as long as the printed program."

Brion discovered his Sousa calling 10 years ago while he was conductor of bands at Yale University and looking for something interesting to spark up his programs.

"I kept coming across Paul Bierley's musical biography of `John Philip Sousa, an American Phenomenon,' " he said. "Bierley described how it was to be at a Sousa concert, and it seemed fascinating, different, new to me, though I had been a band leader for 25 years.

"We looked at the New Haven papers for the many years Sousa came there. We read that one time when he conducted in Wolsey Hall, he had an attack of malaria (contracted hunting in swampy territory near Washington, D.C.) and had to be carried off the stage!

"We thought, we are playing on that very same stage, let's recreate his style of program, dress up in Sousa-style costumes and not just give a tribute, but try to bring to life the actual experience."

Brion's interest in this re-creation has led to extensive research, in libraries, newspapers and museums, interviews with former Sousa band members, and study of old recordings. And his enthusiasm has carried him across the U.S., where in the persona of Sousa he has conducted a majority of the country's orchestras (virtually all that have pops seasons) and many regional ones.

Brion's been overseas and to Canada. Last year he did 41 concerts, and expects this year to go as well. Among his Sousa projects was "The New Sousa Band on stage at Wolf Trap," a PBS television special made in May 1986.

"Sousa was the father of the modern pops concert," said Brion, "the model for Arthur Fiedler, who was playing violin in the Boston Symphony and attended many Sousa concerts in the '20s, when Sousa was at his peak of popularity. Indeed, Sousa was one of the most popular music entertainers in America for 40 years (1896-1936), and the mainstay of Victor records. He made 1,190 sides of 78s on that label, and sold more records than Caruso.

"On his earliest national tours he played not just the cities but many whistlestops, sometimes drawing three times the population of a small town. Later, as wealth came to him he self-produced his tours, but by then the players were traveling in Pullman cars! In 1911 he toured the world and took a slight loss, but felt the publicity was worth it."

Sousa was born in Washington, D.C., in 1854 to a professional trombonist who early recognized his talent. He studied violin, music theory and composition with European-trained teachers, so he was no primitive when he began to compose.

Tickets ranging from $10 to $15 are available for the Utah shows at a variety of locations - at Smith'sTix, at Symphony Hall Monday through Friday from 10 a.m. to 5:30 p.m. and one hour prior to performances, or at the gate. Deer Valley tickets are available at Deer Valley Lodging, Central Check-in and the Kimball Art Center; at Snowbird, at the tram ticket window. Admission at Deer Valley and Snowbird costs $2 extra at the door.