
Start and stop Live Loops cells in Logic Pro for Mac
You can start and stop cells individually, or start and stop all the cells in a scene (a column in the grid) simultaneously. Only one cell can play on a track at any time. You can select one or more cells in different scenes and queue them to play together. While a cell is playing, a circular indicator in the middle of the cell shows the current playback position. If cell looping is turned off, a rectangular indicator shows the current playback position.

The point in time when a cell starts or stops is determined by the Quantize Start value. Quantize Start ensures that cells start at musically meaningful positions (beats or bars), so they are in sync with other cells and the project playhead position. You can change the Quantize Start value for the grid, for scenes, or for individual cells. Triggered cells flash to indicate that they are queued to start at the next quantize start point.
If you trigger a cell too late to start at the desired quantize start point, it starts playing at the next quantize start point. The cell will still be in sync with the project tempo, but it might lead to undesirable musical results, especially when cells are following a short quantize start value. Smart Pickup ensures that cells start immediately at the correct position, even when triggered slightly late. However, this can result in the beginnings of the cells being skipped in order to ensure that the cells are at the correct position when they start playing. In order to avoid this and ensure that cells start playing from the Start position set in the Cell inspector, turn Smart Pickup off and trigger cells with enough time before the upcoming quantize start point.
Cells in the Live Loops grid play at the project tempo. Apple Loops and untagged loops added to cells automatically play at the project tempo, as do any audio files containing tempo information. When you add an audio file without tempo information to a cell, Logic Pro analyzes the tempo of the audio file and adjusts the file to the project tempo. You can manually edit Smart Tempo and transients in the Cell Editor.
By default, when a cell is playing on a track containing regions, the regions on that track are silent. You can change this behavior using the buttons in the Divider column. See How the Live Loops grid and Tracks area interact.