| 摘要 |
<p>PROBLEM TO BE SOLVED: To effectively control the sound volume by providing an openable/ closable topboard to cover an upper surface of a piano body and an openable/ closable bottom sound board to cover a bottom surface of the piano body. SOLUTION: The grand piano 1 is provided with a piano body 5 and three legs 6. A keybed is fitted to a forward part of a bottom of a column unit, and a bottom sound board 15 made of lauan plywood which is opened/closed so as to cover the keybed is provided on a rear part of the bottom. The bottom sound board 15 is opened/closed around a hinge. In addition, a topboard 11 to open/close an upper surface of the piano body 5 is provided on a side plate 10 of the piano body 10. The topboard 11 is opened/closed between the closed position to cover the upper surface of the piano body 5 and an opened position which is diagonally supported by a prop 12 to be engaged with one of two prop set cup receivers to open/close the upper surface of the piano body 5. The sound volume can be effectively controlled thereby.</p> |
