How did Igor Stravinsky experiment with choral sound in Symphony of Psalms?

In his Symphony of Psalms (1930), Igor Stravinsky applied his characteristic empirical approach to sonority, treating the chorus and orchestra as "sound objects" rather than relying on traditional thematic development.12

Rather than following established musical practices, Stravinsky experimented with chord combinations, spacings, and asymmetrical metrical patterns to achieve a sculptural quality in the music. He viewed rhythm as a cumulative process, building large structures through the repetition of these sound objects combined with subtle variations in interior detailing.1

This method, which also informed works like The Rite of Spring and Oedipus Rex, creates an effect of ritual and solemn reenactment. By focusing on the specific gravity and motion of these sonorities, Stravinsky sought new ways to present the vocal textures of a massed group, moving away from the Germanic tradition of thematic development toward a more ritualistic and objective musical language.12