| 摘要 |
A piano plate is provided, preferably on the top surface thereof, with a fine rugged pattern comprised of a number of shallow recesses of various shapes and dimensions for betterment of its resonance characteristics responding to vibrations of a wide variety of frequencies, particularly to vibrations in the treble range, and, when required, for enrichment of aesthetic effect. The vacuum process is advantageously used for manufacturing thereof thanks to its smooth flow of molten metal at casting and easy removal of the cast product from the associated mold.
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