Set Cycles to its maximum value (full right position) for an infinite number of cycles (standard LFO behavior). The LFO is not reset by incoming MIDI note-on messages.
When Cycles is set to values under 100, the LFO is reset by each new MIDI note-on message (Note On Reset).
Your choice to trigger an LFO cycle from the same spot or to allow it to oscillate freely, regardless of phase, should be based on the needs of the sound. The random element of free-running LFOs can make many sounds richer. This, however, can be at the expense of a percussive attack—which is generally inappropriate for drum sounds.
Tip: Try small Cycles parameter values, with the LFO source used to control the Volume (Level) of one or both oscillators. This results in drum flams or hand claps. You can also use minor shifts of the LFO phase, with the Cycle value set to Infinity, to add an analog character to a drum sound.
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Logic Pro User Guide: PDF