Click the Play button in the timing toolbar above the Timeline.
All audio tracks in the project that are turned on and not muted play back.
You can scrub an audio track to hear the audio in your project as you drag the playhead.
Press and hold the Option key while dragging the playhead in the Timeline, mini-Timeline, or Audio Timeline.
Pausing while dragging (but continuing to press and hold the Option key and mouse button) loops the five frames adjacent to the current frame.
Audio looping while scrubbing is turned on by default. You can turn off looping by choosing Motion > Preferences, clicking the Time icon, then deselecting the “Loop audio while scrubbing” checkbox.