PURPOSE: To provide the effector which reproduces reverberation effects in a specific space precisely in another space.

CONSTITUTION: A musical instrument body 1 is provided with plural hall selection switches 3... corresponding to well-known halls such as the Carnegie Hall and the Munich Philharmony hall, a speaker 5, and a microphone 6. A ROM arranged in the musical instrument body 1 is stored with reverberation characteristics of the well-known halls corresponding to the hall selection switches 3. The speaker 5 generates a specific reference sound when reverberation characteristics in an optional space are detected and the microphone 6 detects the direct sound of the reference sound generated by the speaker 5 and its reflected sound. The reverberation characteristics in the space are extracted from the direct sound and reflected sound in the space detected by the microphone 6 and compared with reverberation characteristics of a hall selected through the operation of the hall selection switch 3, and effect processing is performed by using parameters based upon the comparison result.