Musical tone control system for electronic keyboard instrument

A musical tone control system for an electronic keyboard instrument having a let-off mechanism for imparting a let-off effect in accordance with depression of a key, comprising:

• first key depression information-detecting means for detecting key depression information on the key at a first position corresponding to a key depression depth obtained before start of a let-off by the let-off mechanism, as a first key depression information item;
• second key depression information-detecting means for detecting key depression information on the key at a second position corresponding to a larger key depression depth than the first position key depression depth, which is obtained around start of the let-off as a second key depression information item;
• third key depression information-detecting means for detecting key depression information on the key at a third position corresponding to a larger key depression depth than the second position key depression depth, which is obtained after the termination of the let-off as a third key depression information item;
• key depression velocity-calculating means for calculating a key depression velocity of the key, based on the detected first and second key depression information items;
• tone volume-setting means for setting tone volume of a musical tone, based on the calculated key depression velocity of the key,
• sounding timing-setting means for setting sounding timing for sounding the musical tone based on the third key depression information item;
• and
• sounding stop timing-setting means for setting sounding stop timing for stopping sounding of the musical tone, based on the first or second key depression information item,
• wherein said key depression velocity-calculating means includes key depression velocity-correcting means for correcting the key depression velocity calculated based on the first and second key depression information items, according to the first and third key depression information items or the second and third key depression information items.