iMovie for iOS (iPad): Remove an audio clip
Remove an audio clip from a project
With your project open, in the project timeline, tap and hold the blue or purple bar, or the green block, that represents the audio clip until it pops off the timeline.
Drag the clip out of the timeline until you see the puff of smoke in the corner of the clip, then release.
You can also double-tap the audio clip, then tap Delete Clip in the window that appears.