Originally posted by polliccio:
IMHO both are good digital pianos even if they use different approaches to generate sounds (Yamaha=sampling, Kawai=digital imaging) influencing the final results.
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Introduction[/b]
A fine concert grand piano is capable of producing an incredible range of dynamic expression – from very delicate pianissimos to bold and brilliant fortissimos. In between, there is a virtually infinite amount of subtle shadings in tone.

At each dynamic level, the harmonic structure of the piano’s sound changes dramatically. The timbre (tone) of a note played softly is very mellow because the harmonic structure is less complex. As a note is struck harder and harder, the harmonic structure becomes more complex – so the sound becomes more complex.

In order to produce a more accurate digital recreation of the entire dynamic range of a piano, Kawai departed from the standard PCM multi-sample playback methods and created a radically different method.

What is Harmonic Imaging?[/b]
Harmonic Imaging is a proprietary method of sound reproduction developed by Kawai. Simply put, it gives our digital pianos the ability to re-create the entire dynamic range of one of the world's finest concert grand pianos.

Harmonic Imaging uses its special capabilities to alter sound to recreate the harmonic structure of the EX Concert Piano. This capability enables all of our digital pianos to re-create the sound of the EX piano with a range of expression and smoothness that other digital pianos simply cannot match.

How others do it...[/b]
When a piano sound is sampled, only a minute portion of its total dynamic range is captured. Samples are only small examples of a sound, not the entire picture. Even when a piano sound is “multi-sampled”, only a few portions of the multitude of tones are recorded.

Think of a sample as an audio “snapshot”. If you take two snapshots of your friend – one smiling and the other one frowning – you have two samples of how your friend looks. But what about the huge range of expressions in between? You are missing hundreds of subtle expressions that make up your friend’s character.

Ordinary technologies relying only on sample playback for timbre change can get the “smile and frown” of a piano, but most of the dynamic range will be missing. Therein lies the limitation of typical PCM multi-sample playback.

Because Harmonic Imaging relies on its unique capabilities to create dynamic changes, it can produce a smoother transition of tone colour from the softest playable note to the loudest note. Each key strike produces a totally new tone colour true to the original EX Concert Piano.

How does Harmonic Imaging work?[/b]
Using the anechoic chamber at our grand piano research facility, a team of sound specialists created a three dimensional map of the harmonic structure of the EX piano. The harmonic structure of each of the 88 keys was mapped from the softest note playable to the loudest.

Armed with this data, Kawai engineers created a map of the EX’s harmonic structure, plotting the changes throughout the entire dynamic range. When you play a note on a Kawai digital piano, the note is referenced to the map of the harmonic structure of the same note, at the same volume level on the EX piano. Harmonic Imaging then re-creates that same timbre (tone) on the Kawai digital piano.

The result is an amazingly accurate range of tone and expression, with perfectly smooth transitions from the softest note to the loudest. Illustrated here by the perfect picture (pic 1), whilst PCM Sampling can only offer part of the picture, missing the finer details (pic 2). For a visual comparison imagine the difference between a low quality photograph to that of a high definition photograph.