who invented the one-piece cast-iron frame for piano?
<answer> Alpheus Babcock has invented the one-piece cast-iron frame for piano. <context> In 1825, Alpheus Babcock of Boston invented, developed, and patented the one-piece cast-iron frame, which allowed the frame to sustain the nearly 40,000 pounds of string tension and therefore let the piano produce a more powerful and sustained sound. It also allowed makers to use thicker strings, especially in the lower register of the piano. It further eliminated the need for the instrument to have a closed bottom, which until then had helped structural firmness. The 340-pound one-piece cast-iron frame was a major development in the history of the piano. Pedals The Piano Pedals The Pedals