Abstract: A limited number of top octave synthesizer tone generating circuits for producing various tones are used in an electronic organ. Each of the top octave synthesizer circuits is capable of producing any tone which can be produced by the organ. An assignment circuit is employed to assign different ones of the top octave synthesizers to produce the tones represented by different key closures. Because of the limited number of tone generator circuits employed, it is possible under some circumstances to attempt to cause the organ system to produce root tone outputs in excess of the number of top octave synthesizer circuits used in the system. When this occurs, a root tone for a new note is assigned to the top octave synthesizer circuit which is farthest into its decay mode of operation, thereby terminating the tone previously produced by that top octave synthesizer circuit earlier than would be the case if the full decay of that tone were permitted to take place.