Cyclic sound-objects

Any sound-object may contain a periodical part starting at an arbitrary point of its time-span interval. Clicking the "Period (cyclic object)/strike mode" button on the dialog shown Fig.2 displays a dialog for declaring periodicity.

Cyclic sound-objects are handled in a particular way: if their dilation ratio in the performance (see §3.1) is larger than 2, they are repeated instead of being dilated. An example is given with "-da.preroll". The item

{C6 B5 A5 G5 A5 B5 C6, cycle1}

contains 'cycle1', a sound-object which has a periodical part in the last 60% of its time-span interval. The resulting time setting is shown Fig.6. The non-periodical part (40% of the duration) is first performed, then the periodical part is repeated 7 times in synchronisation with the sequence of simple notes.

Fig.6 A performance with a cyclic sound-object

Note that the pivot of 'cycle1'is set at the beginning of its periodical part to ensure its proper location.

There are two typical cases of periodicity, both handled by BP2:

• The sequence of events in the periodical part must be sent again to the sound device when that part is repeated. This happens for instance with sound-objects handled by a MIDI synthesizer.
• The object is declared cyclic but there is no need to repeat the sequence in the periodical part. This happens with sound-objects handled by a MIDI sampler. The sampler expects BP2 to trigger the process with a NoteOn and then it takes care of repetitions until a NoteOff is received.
In the latter case, property "Discard NoteOff's except in last period" should be activated. It prevents the sampler from setting off as soon as the first cycle has been completed. This property is generally completed with "Don't strike again NoteOn's" accessed in the same dialog and documented on-line.

Property "Force integer number of periods" adjusts the durations of sound-objects to make sure that the last repetition of the periodical part will be complete. It is only required in case the acceptable dilation ratio of the sound-object (see reference manual §3.1) is less than 2.