1. Field of the Invention
The present invention relates to an electronic musical instrument, such as an electronic piano, which produces various effects in accordance with the amount of operation of a pedal.
2. Description of the Related Art
Various attempts have been made to make electronic keyboard instruments, such as a piano, using electronic technology.
An electronic piano is a typical type of electronic musical instrument and is provided with a foot-operated switch, such as a damper pedal, sostenuto pedal or soft pedal. The damper pedal reduces a reverberation when turned off and increases it when turned on. The sostenuto pedal, when operated, sustains the key-on status of a key on a keyboard that is operated or depressed to thereby provide a damper effect for each key. The soft pedal reduces the overall volume and provides a soft output sound by varying a filter characteristic.
FIG. 1 is a block diagram illustrating a conventional electronic piano. In the illustrated electronic piano, a CPU (central processing unit) 114 receives data about an operated amount from a keyboard 111, various switches 112, and various pedals 113. CPU 114 controls a memory 115 such as a ROM or a RAM for storing a predetermined program and data and also controls a tone generator 116 and envelope generator 117 in accordance with the operated-amount data. The output of envelope generator 117 is supplied to a sound system 118 from which it is outputted as a musical tone.
A description will be given below of the operation of such an electronic piano with the damper pedal operated. An envelope of an attenuating sound such as a normal piano sound has a long release portion as indicated by "A" in FIG. 2A. When a key off occurs with the damper pedal being in the OFF state, a high release envelope is attained which rapidly falls as indicated by "B" in FIG. 2B. With the damper pedal being ON, even when a key off occurs, a resultant sound follows the envelope A. That is, a sound is generated according to the envelope B only when both a key and the damper pedal are OFF and it is generated according to the envelope A when either one is ON, as shown in FIG. 3.
With regard to an electronic musical instrument with such a pedal, Japanese Patent Disclosure No. 54-23518 discloses technique using a touch release circuit in an electronic musical instrument, which can render a musical tone after key release in a desired sustain state.
Japanese Patent Disclosure No. 58-97092 discloses an electronic musical instrument having the same function as a sostenuto pedal.
Further, Japanese Patent Disclosure No. 61-172192 discloses a conventional technique for controlling the volume, timbre or the like of a musical tone in accordance with the operational status of an operating element, such as a pedal, and the key-touch status.
Let us now consider an acoustic piano. FIG. 4A is a conceptual diagram of a damper section of an acoustic piano, and FIG. 4B is a side view of FIG. 4A. In these figures, each string 121 is provided with a damper 122 which individually operates upon occurrence of a normal key-on/off. Each string 121 has its both ends fixed and its vibration is transmitted through a bridge 123 to an echo plate 124. Stepping on a damper pedal 125 releases all the dampers 122 at the same time. The vibration of that string 121 which is directly vibrated by a hammer (not shown) is transmitted to other strings 121, thus providing rich sounds. In other words, operating damper pedal 125 produces two prominent effects: sustaining of a long envelope from a key-on to a key-off and rich sounding by opening all the strings.
However, the conventional electronic musical instrument can only provide the effect of maintaining a long envelope by operation of, for example, a damper pedal, but cannot provide a sound effect such as rich sounding realized by full open strings in an actual acoustic piano, etc.
For instance, the techniques disclosed in the aforementioned Japanese Patent Disclosure Nos. 54-23518, 58-97092 and 61-172192 are concerned with controlling the volume, timbre or the like of a musical tone by operating various pedals, and nothing is proposed there which is concerned with a technique of adding various effects to a musical tone at the same time.