In conjunction with electronic musical instruments, and more particularly electronic organs, there has been substantial development in the area of automatically controlled rhythm accompaniment devices used to produce percussion rhythm patterns on selected instruments as controlled by the musician playing the organ. Generally, such organs are capable of producing a number of various rhythm patterns which are selected by a selection switch; and each of the patterns are capable of reproduction at various beat frequencies, also under control of the musician.
Systems also have been developed for pedal tone pattern generation, typically in conjunction with a string bass tonal effect, in which the musician selects a root or tonic note which is harmonious with the keyboard notes he is playing. The tone pattern system then produces alternating chordal or tonal effects based on the selected tonic root note, and these tonal effects are produced in cooperation with a rhythm system in the organ or musical instrument.
One disadvantage to the systems which have been utilized in the prior art to produce alternating bass tonal effects, which otherwise may be termed "walking bass" tonal effects, is that of providing maximum flexibility of control to such systems by the musician. Most such systems do not permit independent playing of the notes of the pedalboard when the automatic or "walking bass" system is switched into its operative mode. In addition, such systems in the past have a fixed pattern or pattern cycle which is continuously repeated within the organ, irrespective of the playing of different notes on the pedalboard by the musician. This forces the musician's playing to be slaved to the unvarying automatic pattern which he has preselected. Thus, any change from one root or tonic note to another by the musician must be made by him in synchronism with the automatic pattern or musically strange or unpleasant effects result. For example, if the automatic "walking bass" system is generating a tone pattern of four notes repetitively, and the musician desires to change to a new tonic note at the second note of such a pattern, the prior art systems generally continue the pattern; so that when the new tonic note is selected by the musician on the pedalboard, the effect merely is to transpose the generated tones to the second chordal note of the pattern associated with the newly selected tonic note without first playing the tonic note. The tonic note then only is sounded or played after the automatic system completes its cycle and commences a new cycle. This has been found to be very frustrating to many musicians who wish to have flexibility in their playing to select and sound a new tonic note and restart the "walking bass" pattern at the beginning, irrespective of where they interrupt the previous pattern by playing a new tonic note.
Furthermore, systems of the prior art also have resulted in some unusual effects being produced when a musician plays a pedal key slightly out of synchronism with the automatic rhythm generated within the organ. This often produces a double playing of the tonic note, once when it is fist selected by the musician and a second time in response to the automatic pattern. Or the first two notes of the pattern are played in rapid succession, with the remaining notes of the pattern then being played in their normal sequence at the proper time or beat intervals. Once again, this is a result of the slaving of the musician's playing to the internal automatic timing of the organ, rather than causing the timing of the "walking bass" operation of the organ to be dependent on the manner of playing effected by the musician.
It is desirable to provide a system for automatically producing tone patterns based on a tonic note in an electronic organ which provides a greater degree of flexibility to the musician than previously has been attainable with prior art systems. More specifically, it is desirable to cause each tone pattern to be restarted at the beginning each time the musician selects or plays a different pedal note. It also is desirable to permit the musician to override the automatic tone pattern system whenever he desires to play different tone patterns of his own choosing or to momentarily change the walking bass tone patterns and then subsequently revert back to the automatic system.