One of the most remarkable performances at the Spokane Symphony’s Masterworks 3 presentation on Saturday night took place before the first note was played. During the preconcert lecture from the stage of the Martin Woldson Theater at the Fox, guest conductor Darko Butorac began to describe one of the pieces he had selected for the program: Sergei Prokofiev’s Symphony No. 5 in B flat Op. 100. Instead of providing a general introduction to the background and structure of the piece, and perhaps some speculation as to the composer’s intentions, Butorac distilled a verbal description of every significant musical detail of Prokofiev’s epic tapestry, tracing themes, harmonies and instrumental entrances. He traced motives and melodies as they passed from one instrument to another, passing through sections or whole movements until attaining their full significance at the symphony’s close.