Electronic musical instrument which prevents tone generation for partial

Abstract

An electronic musical instrument employing a keyboard unit provides a position sensor with respect to each of plural keys so as to detect a depressed position of the key in a real-time manner. A key-operating velocity is calculated from the depressed positions of the key which are sequentially detected by the position sensor. A critical velocity is determined in advance with respect to each of the depressed positions of the key. The critical velocity is defined as a minimum velocity by which a hammer can strike a string when a hammer moves from a position corresponding to each of the depressed positions of the key. One of the channels is selected in accordance with a predetermined algorithm on the basis of a result of a judging operation which judges whether or not the key-operating velocity exceeds the critical velocity corresponding to a current depressed position of the key. Then, a tone-generation task to produce a musical tone signal responsive to a key-operation event is assigned to a selected channel. On the basis of the key-operating velocity and the result of the judging operation, a start timing to produce the musical tone signal is designated for the selected channel. Thus, the selected channel produces the musical tone signal at the designated start timing.