Abstract: A preferential order of channel vacating is determined according to a musical character of musical tones having assigned channels, thus permitting a channel assignment which does not depart from the harmony of the musical tone. The greater the number of tones which are equivalent in musical character, the more readily channels can be vacated for new tones, and tones with fewer equivalent tones in musical character may remain assigned. The channel selection may also be limited for low envelope level tones.