We defined a rhythmic pattern as a succession of musical events contained within a single metric unit that corresponds to a single main beat. As it contains 4 beats of 16th note level there are 24 = 16 possible combination of events within a pattern.
As mentioned before, all main beats are being played in bass voice. This effectively eliminates all patterns starting with a rest, which halves down the remaining number of patterns. However, as some of the patterns that start with a rest show up occasionally in anacrusis, transitions and cadences, we will also include two of those, so that in total our system contains 10 rhythmic patterns.
For the sake of simplicity rhythmic patterns are notated without rests, with the exception of those that start with a rest. The presence of the note indicates a note's onset at the given beat, however the absence of the rest doesn't indicate that the note from the previous beat is to be sustained until the next note. In real songs we can often hear the same pattern played with both staccato and legato techniques. This has to be dealt on a case by case basis.
It may be shown that whenever a binary (2) beat group of additive rhythm component is aligned to the main beat of divisive component it yields a composite rhythmic pattern containing strong beats only. Those are simple but important patterns that stimulate entrainment process and we will classify them as entrainment patterns. It will be shown later that all basic rhythmic phrases contain at least one pattern of this type.
Most important characteristic of the first pattern is that it contains all beats from the first subdivision of metrical unit. This pattern appears in almost every rhythmic phrase and will be treated as main entrainment pattern.
Next two patterns are produced by removing one beat from the main entrainment pattern and are usually played in cadences and transitions.
Rest of the patterns are produced by adding one or two beats from the next subdivision level to main entrainment pattern. They usually appear only in transitions.
Whenever a ternary (3) beat group of additive rhythm component is aligned to the main beat of divisive component it yields a composite rhythmic pattern containing one strong and one weak beat.
The first pattern is created when the onset of the ternary beat group is aligned to main beat of divisive component. Most often it marks the beginning of the rhythmic phrase, but under some circumstances it may also end the phrase.
The second pattern is created when the ending of the ternary beat group is aligned to main beat of divisive component. Likewise it usually marks the end of the rhythmic phrase, but under some circumstances it may also start the phrase.
Finally, the last pattern is created by removing first beat from the first polyrhythmic pattern. It is mainly used in anacrusis and transitions.
We classify all patterns that contain weak beat without a following strong beat as syncopated. They may be produced either by polyrhythmic composition or by deliberate syncopation.
The first pattern shows a typical syncope. It is created whenever a binary beat group is contained within a single metrin unit but not aligned by ether it's onset or ending to any of the main beats. It may also be created by deliberate syncopation of second polyrhythmic pattern when a melody or chord that is expected to be played at the following main beat is moved to preceding last weak beat of the current pattern.
Second pattern may be created by deliberate syncopation of main entrainment pattern under same conditions as described above.
Rhythmic Patterns: Summary
It might be convenient to designate a numbering scheme for most often used rhyhtmic patterns. That way it will be easier to memorize and later recall them from memory while playing. As there is no standard for notating rhythmic patterns we will propose a numbering scheme as shown below:
Patterns 1 to 4 are used to build basic rhythmic phrases, while the rest are mostly used in transitions and cadences.