His death was confirmed by his wife, Avis.  Mr. Herseth was the symphony’s principal trumpet from 1948 to 2001, a stretch roughly double the average career span for elite instrumentalists and coinciding with the orchestra’s rise to the top ranks. Under Georg Solti and four other conductors he defined the orchestra’s distinctive brass sonority.  The sparkling virtuosity of his playing — and the way his cheeks flushed beet-red when he played staccato high notes — made Mr. Herseth something of a celebrity among classical music audiences in Chicago. Autograph seekers often mobbed him at the stage door of Orchestra Hall, a trumpet player or two usually among them asking to study at his feet.  But outside Chicago he was considered a buried treasure. Describing Mr. Herseth as “quite possibly the most dazzling player on his instrument in the world today,” Donal Henahan of The New York Times lamented his relative obscurity, attributing it largely to the paucity of great music for orchestral trumpet.  “If Beethoven, Brahms and Mozart had left a repertory of trumpet concertos, Mr. Herseth might be as familiar to the world as Heifetz, Horowitz or Rostropovich,” Mr. Henahan wrote.  By his own account, Mr. Herseth, a genial, plain-spoken native of rural Minnesota, did not seek wider fame, saying he found more pleasure in collective music-making than in solo playing.  “That’s the biggest thrill of all,” he told The Chicago Tribune, “just to be in a band like this, with colleagues like these, and with conductors for whom we can make exciting music.”  For his 50th anniversary with the symphony, in 1998, Mr. Herseth resisted plans for a gala event that would have put him in the spotlight — “tooting my own horn,” in his words.  Instead, he invited a large contingent of colleagues, former students and old friends, including the trumpet player and former “Tonight Show” band leader Doc Severinsen, to join in the concert.  Adolph Sylvester Herseth was born on July 25, 1921, to Cora and Adolph Herseth in Lake Park, a town of only several hundred people in northern Minnesota’s lake country. His father was a schoolteacher, school administrator and director of a children’s orchestra.  “It was a very musical culture,” Avis Herseth said in an interview on Friday. She met her future husband in the trumpet section of the fourth-grade band in neighboring Bertha, Minn. “Everybody played something, or sang in the church choir.” (She did both, she said.)  Avis and Adolph, who was known as Bud, were married in 1943. In addition to his wife — “the only girl I ever dated,” he told an interviewer — Mr. Herseth is survived by a daughter, Christine Hoefer; a son, Stephen; six grandchildren; five great-grandchildren; and a brother, John.  Mr. Herseth graduated from Luther College in Decorah, Iowa, intending to become a music teacher. But after serving in the Navy during World War II and playing trumpet in military bands, he decided on a career as a performer.  In 1948 he was working on a master’s degree at the New England Conservatory of Music in Boston when he received a telegram from Artur Rodzinski, the Chicago Symphony’s music director, summoning him to an audition. Someone at the conservatory must have recommended him, Mr. Herseth said later. He never learned who.  The audition was a stunning success. To Mr. Herseth’s surprise, Mr. Rodzinski announced immediately afterward that Mr. Herseth, then 26, would be the new first trumpet.  The emotional energy and perfectly articulated sonic detail for which Mr. Herseth became known are prominent in many of the Chicago Symphony’s most acclaimed recordings, including Mahler’s Fifth Symphony and the “promenade” parts in Mussorgsky’s “Pictures at an Exhibition.”  After giving up his post in 2001, Mr. Herseth held the title of first trumpet emeritus until 2004, when he officially retired.  John Hagstrom, who sat next to Mr. Herseth for several years as second trumpet, recalled a story about a conductor who seemed unnerved by Mr. Herseth’s red-faced appearance during the most taxing trumpet passages. “Mr. Herseth, maybe put on some powder,” the conductor suggested.  Mr. Herseth demurred, he told Mr. Hagstrom. “It shows people I’m trying,” he said.
Mr. Herseth was the principal trumpeter of the symphony for 53 years and one of the most accomplished and influential orchestral trumpeters of his time.