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Like good titles, getting the audio right in your movies is something that, with a small amount of effort can pay big dividends. Rather than festoon iMovie 4 with a battery of audio effects and filters, Apple has aimed for ease of use. Adding voiceover narration and a music backing track is virtually a no-brainer, and the audio tools on the Advanced menu provide all you need to achieve the sort of sophisticated sound edits that are a staple of professional video productions.

iMovie 4 provides two audio tracks in addition to the stereo audio that accompanies your video clips. This is usually invisible, but you can separate it from the video clip and edit it in one of the two extra audio tracks. These audio tracks can also accommodate music, voiceover narration and special effect sounds.

Easy-to-use, keyframeable volume controls provide the means to balance individual sound components and to add emphasis where you want it. About the only thing iMovie lacks is a means of panning - positioning stereo sound within the audio space created by left and right stereo speakers.

This masterclass demonstrates basic use of the volume controls to fade audio in and out, and shows how to use the Paste Over command to insert video into the Timeline while leaving the original audio untouched. We will also take a brief look at recording voiceovers and adding special effects.

Like visual editing, success with audio depends on not overdoing it and getting the balance right. Judicious use of these simple audio volume and pasting techniques in combination with carefully balanced backing music, voiceover

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narration and special effects will provide your movies with a much more professional audio feel.

Recording better audio

Although you can do a lot at the editing stage to improve the aural experience, there is no substitute for getting good-quality sound at the shooting stage. No amount of editing will make up for the fact that you cannot hear the best man's speech on your sister's wedding video, even though the camcorder's built-in microphone did a splendid job of picking up the conversation on the table you were sitting at while shooting.

So the first piece of advice is to use an external mic whenever possible. Built-in camcorder mics can be good at picking up sound close to the camera, sometimes including tape transport motor noise, but they do less well with distant subjects. If you are working outside, make sure to use a windscreen to protect the mic from wind noise.

If your camcorder has a headphone socket, use it to monitor the sound so that any problems are immediately apparent and you can correct them before it is too late.

If you are recording an event, using two camcorders makes life a lot simpler. Set up one camcorder on a tripod for a long shot taking in the entire stage, record the sound on this camcorder and leave it running continuously for the performance. Use the second camcorder for close ups, audience shots and so on. Use the Paste Over technique described in the workthrough to edit in shots from the second camera while maintaining the soundtrack.

For best-quality sound recording, set your camcorder to record in 16-bit audio mode. This will provide you with the highest sound quality, as 16-bit audio is sampled at 48kHz. 12-bit audio mode only records sound at 32kHz.

Add depth to your audio

If your recorded sound is a bit weedy, you can give it extra depth and volume simply by duplicating it. Select the video clip in the timeline viewer and press command-J to extract the audio. Next, select the extracted audio and alt-drag it to the second audio track directly below the first to duplicate it. To add a reverb effect, shift the second audio track along a few frames (five frames is a fifth of a second).