Velocity calculating system for moving object widely varied in velocity method for correcting velocity and keyboard musical instrument equipped with the velocity calculating system for accurately determining loudness of sounds

A keyboard musical instrument comprising:

• a keyboard having plural keys movable between respective rest positions and respective end positions;
• plural hammers respectively associated with said plural keys, and driven for rotation for generating tones;
• an action mechanism provided between said plural keys and said plural hammers for transferring motions of said plural keys to said plural hammers;
• a velocity calculating system including
• plural hammer sensors respectively associated with said plural hammers, each of said plural hammer sensors having
• a rigid member provided with plural detectable positions spaced from one another along a trajectory of associated one of said plural hammers and defining plural distances and
• a sensor monitoring said rigid member and changing a hammer position signal at every detectable position, one of said rigid member and said sensor being connected to said associated one of said plural hammers, the other of said rigid member and said sensor being stationary with respect to said associated one of said plural hammers,
• plural key sensors respectively associated with said plural keys and respectively monitoring said associated keys for varying key position signals depending upon the actual key positions of said associated keys, and
• an information processor connected to each of said key sensors so as to calculate a key velocity of associated one of said plural keys depressed by a player and each of said plural hammer sensors so as to calculate a first hammer velocity on the basis of one of said plural distances and a first lapse of time thereover and a second hammer velocity on the basis of another of said plural distances shorter than said one of said plural distances and a second lapse of time thereover and determining one of said first hammer velocity and said second hammer velocity to be a representative hammer velocity depending upon the value of said key velocity;
• and
• a music data information generator connected to said information processor and generating pieces of music data information representative of the keys depressed by said player and the loudness of said tones each proportional to said representative hammer velocity.