How to Improve the Sound of Video Clips in iMovie
Your Apple iMovie video clip looks great, but the sound in one video clip is barely audible, while in another you must turn down the volume. Fortunately, you can tweak the audio in your video so that the sound remains consistent from one scene to the next.
Start by clicking Audio Adjustments in the toolbar to display various slider controls. If you want to adjust the volume of a single clip, select it and then drag the volume slider to the appropriate level. Click Done when the sound is correct or select another clip and adjust the sound in that one as well.
You can always restore the volume to its original level by clicking the Revert to Original button.
If you want to normalize the volume across all your clips, select a clip and click Normalize Clip Volume. iMovie makes sure that the clip is as loud as it can be without distortion. Now choose another clip and do the same. The two clips are now within the same normalized range. Keep normalizing clips in this manner until they all sound the way you want them to.