How To Edit Sound In IMovie
In the previous film in this series, "How to edit video in iMovie" we showed you how to get ready to edit your footage, and now we're going to show you how to deal with the sound of your project.
This guide covers iMovie HD 6, but up-to date information and help about other versions can be found at www.apple.com/support/imovie/
You've polished the look of your project, so now it's time to polish the way it sounds. There are three areas that will need your attention: The volume of your existing footage, the musical score and spot sound effects. The reason to deal with sound after picture is that your movie should work well even without the added atmosphere of a musical score, so make sure you are happy with the way it plays based on picture alone first.
First, you should tidy up the volume of your clips and make sure they are roughly equal to each other - unless you deliberately want a certain clip to be louder or quieter then the others for creative reasons. iMovie HD hides the clip volume controls by default, but to turn them on go to the top of the screen, select "View" and then "Show Clip Volume Levels". In timeline view, your clips will now have a line through them. Using this slider it is easy to adjust the volume of each clip. Keep listening to the join between two clips you've adjusted to judge if they work well together.
An advanced technique is to click on the line in the clip itself - this allows you to change the volume levels several times within a clip. The yellow ball controls both the end volume level and at what point this volume is reached. The purple box controls similar functions for the beginning of the volume change. Move both around until you are happy with the new sound of the clip, then click outside the clip to "set" the change. With this done, you can click on different points inside the clip again to make further adjustments. If you want to undo your changes, either use the "Edit" and "Undo" option at the top of the screen or grab the purple ball of each volume adjustment on the clip and drag it back to the original sound level. The line will become dotted when you drag the adjusted volume back to the same level as the rest of the clip. When you're finished, use the "View" menu to hide the clip volume levels to avoid making any accidental changes.
To add music and effects to your project, you will be using the two bottom rows of the timeline. Click the "Media" button and then the "Audio" option at the top. In this window you have a choice of pre-recorded sound effects, or you can record your own sounds if your Mac has a built in Microphone (most do). You can drag any of these onto either of the two bottom rows of your timeline and also use this window to select either your own Garageband compositions or songs from your iTunes library. You can also drag tunes or sound effects in from the desktop, so long as it's an .mp3, .wav or .aiff file.
Drag the playhead to where you want your song or sound to begin and when you drag the file from the audio window, it will automatically lock onto that position. Once your song or effect is on the timeline, it's length and volume can be edited in the same way as a normal video clip. Note the three tick boxes to the right of the timeline. By ticking or unticking these, you can turn the sound for an entire row on or off. If you just want to hear the your music tracks, turn the top video row off, but remember to turn it back on again when you're done.
When it comes to sound effects, you can put as many sounds as you like on any one row as they will overlap with each other and existing music tracks - just try not to lose track of which one is which! Remember that in video's where the dialogue has to be heard, the music and effects should never overpower the spoken word. A good balance to start with is boosting the volume of the video clips to around 130%, and reducing the music to around 10%. Spot effects can be louder so long as they are brief and don't interfere with the dialogue. iMovie also features a few tools for removing background noise or adding echo - you'll find them under the "Audio FX" button of the "Editing" section.