RX-1 stvara predivne, bogate i rezonantne tonove i on se svojom veličinom od 164 cm odlično uklapa u bilo koju klavirsku sobu.
The soundboard is the very heart of the piano's tone. Its purpose is to transform the vibrations of the piano's strings into a beautiful, resonant tone. Kawai uses only straight-grained, quarter-sawn solid spruce for all grand piano soundboards. Each one is tested with state-of-the-art equipment to measure the speed at which sound energy travels through it. Only those soundboards that exceed our demanding resonance standards are selected for use in Kawai grand pianos.