Quantize audio regions or cells in Logic Pro for iPad
When quantizing a MIDI region, Logic Pro for iPad moves the individual notes to the chosen quantize grid. An audio region, however, represents a waveform, a continuous flow of alternating values. To use a quantize command on an audio region, Logic Pro first performs the Smart Tempo analysis to detect transients (sudden level changes) in the audio signal and marks those positions with transient markers. The quantize command then moves those transient markers (and that portion of the underlying waveform) to the quantize grid, and as a result, stretches sections of the audio signal so that it appears to be quantized based on the settings.
The Region inspector provides four Quantize parameters for audio regions: Quantize, Q-Swing, Q-Strength, and Q-Range.
In addition to the Flex & Follow parameter that has to be enabled, the Flex parameter in the Track inspector has to be enabled for the corresponding track. The various Flex mode algorithms affect the sonic quality of the quantization results. See Intro to Flex Time.
Quantize audio regions
Tap an audio region to select it, or select multiple audio regions.
Tap the Inspector button
on the left side of the view control bar (or press I on your external keyboard) to open the Region inspector.Tap the Quantize disclosure arrow to show the Quantize parameters.
Tap the Quantize pop-up menu to choose a quantize grid.
The audio region will be tempo analyzed, and the Flex & Follow parameter in the Region inspector will automatically be set to On (if it hasn’t been done yet).
Adjust the values for the Q-Swing, Q-Strength, and Q-Range parameters as needed.
Tip: Tap the Level Up button 
at the top of the Region inspector to show the Track inspector, where you can adjust the Flex Time parameters displayed below the Flex switch.
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