Using Start Sounds

Start sounds behave just like event sounds, with one important difference: Flash doesn't play a new instance of a start sound if that sound is already playing.

To set an assigned sound's Sync parameter to Start

1.	Open OverlapSnds.fla, the file you created in "To play overlapping instances of the same sound" earlier in this chapter. You should have one instance of the Scale.AIFF sound in keyframe 5 and another in keyframe 15. The second instance is in the Sound 1 or Sound 2 layer, depending on what you did in the earlier task.
2.	In the Timeline, select the keyframe 15 that contains the Scale.AIFF sound (Figure 15.17). Figure 15.17. To change a sound's Sync setting, select the keyframe that contains the sound. Then, in the Frame Properties tab of the Property inspector, from the Sync pop-up menu, choose a new setting.
3.	In the Frame Properties tab of the Property inspector, from the Sync pop-up menu, choose Start (Figure 15.18). Figure 15.18. To prevent Flash from playing another instance of a sound if that sound is already playing, choose Start from the Sync pop-up menu in the Frame Properties tab of the Property inspector.
4.	Position the playhead in keyframe 1, and play your movie one time. When the playhead reaches keyframe 5, the Scale.AIFF sound starts. When the playhead reaches keyframe 15, nothing changes; you continue to hear just one voice as the Scale.AIFF sound continues playing. When a sound is playing and Flash encounters another instance of the same sound, the Sync setting determines whether Flash plays that sound. When Sync is set to Start, Flash doesn't play another instance of the sound.

Tip

• To avoid playing multiple instances of a sound when a movie loops, set the sound's Sync parameter to Start. If the sound is still playing when Flash starts the movie again, Flash lets the sound play, adding nothing new. If the sound has finished, Flash starts the sound again when the playhead enters a keyframe containing the sound.