Electronic musical instrument having transient musical effects

An electronic musical instrument of a type wherein a plurality of systems are provided each system comprising memories storing respective harmonic component waveshapes which are read at the same reading rate and the read out harmonic waveshapes are suitably mixed to obtain a desired musical tone. Each system also comprises a circuit for controlling the envelope of the waveshapes read from the memories. In the first system, the envelope control is made in such a manner that the envelope will rise upon depression of a key, thereafter maintain a constant level as long as the key is kept depressed and decay upon release of the depressed key. In the second system, the envelope is controlled so that the envelope will rise in a short time and immediately decay thereafter. The respective harmonic waveshapes thus controlled in envelope in the respective systems are then suitably selected and mixed together. As an example of the envelope control in the second system is shown a structure for producing a so-called "chiff" effect by providing the fractional period during which the envelope rises and subsequently falls at the attack portion of the musical tone. Desired waveshape or waveshapes are selected from among the harmonic waveshapes controlled in the envelope in the second system for mixing with the harmonic waveshapes read from the first system. By this arrangement, amplitudes of the frequency components of the selected harmonic waveshapes are emphasized during the fractional period.