However at the suggestion of the baritone Karl Schmitt-Walter , she switched teachers and started working with the coloratura soprano Maria Ivogün as well as with Ivogün 's husband , the pianist Michael Raucheisen .
In 1934 , Schwarzkopf started to study in Berlin Hochschule für Musik , then she changed teachers and started working with the coloratura soprano Maria Ivogün as well as with Ivogün 's husband , the pianist Michael Raucheisen .
Additional models may have also posed for the figure . The likenesses of both Léon Leenhoff ( Manet 's stepson ) and Victorine Meurent ( Manet 's preferred model ) have been seen in the boy 's face and figure .