The Knabe piano company, founded by William Knabe in 1837. Knabe pianos were renowned for their innovations. William Knabe was one of the early adopters of iron frames in pianos, which greatly improved tuning stability. Knabe introduced duplex scaling, which enhances the harmonics and overtones in the piano's sound. Knabe pianos became an American icon, and they were often favored by renowned pianists and institutions. They were also the choice of the White House for many years, with Knabe pianos being used by several U.S. presidents. In 2009, the Knabe brand was acquired by Samick Music Corporation, a South Korean piano manufacturer. Samick has since been working to maintain the Knabe legacy while producing modern pianos with the Knabe name.