When using Duplicate (or
Repeat) for audio that must fall cleanly on the beat (such as rhythmic loops), it is important that you select the audio material with the Selector tool, or by typing in the start and end points in the Event Edit area. If you select an audio clip with the Time Grabber tool (or by double-clicking it with the Selector tool), the material may drift by several ticks because of sample-rounding.
If, on the other hand, you want to Duplicate (or
Repeat) audio that is not bar- and beat-based, set the Time Scale to any format except Bars|Beats. This ensures that the duplicated audio material has the correct number of samples and is accurately placed.