Shaw was born in California in 1916, into a family of evangelical preachers, and learned gospel songs at his mother's piano. He was one of five children, all of whom were taught the piano and with whom he would harmonise. From 1934 to 1938 he studied religion and philosophy at Pomona College, where he conducted and sang in the glee club.
The entertainer Fred Waring heard him one day and asked him to come to New York, to form and conduct the Fred Waring Glee Club for his weekly radio broadcasts. Shaw's career in the priesthood had been thwarted; a very different one had begun. Shaw's musical tastes were catholic, but glees could not hold his attention for very long, and in 1941 he founded the Collegiate Chorale to allow him to tackle more demanding repertoire.
The Chorale was soon noticed not only for its high standards but also because there were no racial barriers to joining it - Shaw joyfully called it "a melting pot that sings". It was with the Collegiate Chorale, 150 strong and all amateurs, that Shaw began his lifelong engagement with contemporary music, giving many first performances alongside the established classics: Aaron Copland's Lark and In the Beginning, for instance, were both Shaw premieres.
Arturo Toscanini had a reputation of being an extremely difficult conductor to please. But, when he heard Shaw at rehearsal, his comment was simple: "At last I have found the maestro I have been looking for", and he invited Shaw and his Chorale to sing in a performance of Beethoven's Ninth Symphony with the NBC Symphony Orchestra.
Shaw's next group was the one which did most to extend his reputation: in 1949 he founded the Robert Shaw Chorale, professionals and 40 in number. It began as the chorus for opera recordings but soon branched out to make its own LPs, ranging from Broadway hits and folk tunes to the central classical repertoire. Shaw's commissioning policy was, as always, adventurous: Samuel Barber, Benjamin Britten and Darius Milhaud were among the composers who wrote for him.
The Robert Shaw Chorale travelled widely in the 1950s and 1960s, visiting over 30 countries in Europe, the Middle East and South America, often on goodwill tours for the US government. In 1962 they visited 11 cities in the Soviet Union, taking with them - to an officially atheist state - Bach's B minor Mass. Shaw later recorded his surprise that the concert was broadcast - including half an hour of applause at the end.
Shaw's orchestral career was now building up, too. He conducted the San Diego Symphony from 1953 to 1958 and was associate conductor of the Cleveland Orchestra, under George Szell, from 1956 to 1967; he also worked wonders on the Cleveland Orchestra Chorus during his time there.
The Robert Shaw Chorale was dissolved in 1967 when Shaw moved to Atlanta, Georgia, to take up the post of artistic director of the Atlanta Symphony Orchestra; he was to remain there until 1988. Under Shaw's charge the Atlanta orchestra evolved from being a part-time, small-scale, regional orchestra to a full-time, full-size ensemble, and one of the finest in the United States. Unsurprisingly, the Atlanta Symphony Orchestra Chorus and Chamber Chorus, both Shaw creations, also established a reputation for excellence. Here, too, Shaw continued his far-sighted programme of commissioning new works.
In 1977 Shaw took the Atlanta orchestra to Washington to play at the inaugural concert of the President-elect, a local lad, Jimmy Carter. Carter responded by electing Shaw to the National Council on the Arts; over the course of his career Shaw was awarded enough honours to fill a decent- sized suitcase.
His retirement in 1988 left him free to accept conducting engagements elsewhere. More importantly for him, he had the time to realise a long- cherished ambition with the founding of the Robert Shaw Choral Institute, where he could concentrate on the choral literature, not least in the choral festival he established in the South of France.
He also began a series of annual, week-long choral workshops in the Carnegie Hall, New York, which brought in choral directors and singers from across North America. Earlier this month he had to withdraw from this year's workshop because of back problems. He couldn't have known that it would have been his last: he suffered a massive stroke on Sunday evening, and died in the early hours of Monday.
Shaw's technique for rehearsing choruses involved isolating elements in the music - rhythm, pitch or enunciation - to focus attention on them, often with some humour. He would write letters to his singers (beginning "Dear People", a greeting Joseph Mussulman borrowed for a biography of Shaw in 1979) to put his points across, enjoining them (for example) to respect lesser note-values in a manner which suggested the preacher was still alive in him:
I get a horrible picture, from the way you sing, of little bitty eighth notes [quavers] running like hell all over the place to keep from being stepped on. Millions of 'em! Meek, squeaky little things. No self-respect. Standing in corners, hiding under rugs, ducking into subway stations, peering out from under rugs. Refugees. Dammit, you're all a bunch of Whole- Note Nazis!
The Shaw choral sound was beautifully blended and refined, but also rich and full-bodied. It can be heard on the dozens of recordings he made, from the 1940s onwards, winning no fewer than 14 Grammy awards - and it will influence the sound of choral singing in North America and much further afield for many years to come.
Robert Lawson Shaw, conductor: born Red Bluff, California 30 April 1916; married first Maxine Farley (marriage dissolved), second 1974 Caroline Saulas (died 1995; three sons, one daughter); died New Haven, Connecticut 25 January 1999.