Sound structures' advanced settings are specified in the Advanced Settings tab of the object Property Editor to limit the number of sounds playing concurrently and to specify their behavior when they are inaudible, which respectively provide the following advantages:
Advanced settings and mixing
You shouldn't wait too late in the production process to adjust the advanced settings. More precisely, you should at least perform a first pass before or while mixing. If you spend time tweaking your mix too early, and later realize that audio is using too many resources, you might end up using advanced settings so aggressively to keep audio processing within bounds that it would have a dramatic impact on your mix.
Playback limits should actually help you with mixing. Use them as a form of dynamic mixing, to help players focus on what's important instead of drowning them with sounds. You may also use bus ducking, Set Voice Volume Actions, States, or RTPCs to clean up your mix.
Playback limit, priority, and under Volume Threshold behavior
Playback limits used on sound structures help you limit the number of sounds playing at the same time, either per game object or globally as specified in the Actor-Mixer and Interactive Music hierarchies. (In the Master-Mixer Hierarchy, it is always globally). Its logic is solely based on the number of sounds that play. However, sound designers can apply separate limits to different objects throughout a hierarchy. And, as desired, they can also create separate hierarchies by selecting the Ignore Parent option. In sum, the different levels of playback limits provide sound designers with greater and easier control over what will play.
Playback limiting conditions are checked before attempting to play a sound. When a sound is about to start and the limit has already been reached, either this sound or another one is stopped. The first criterion is the sound's priority. In the case where the two candidates have the same priority, the sound engine stops either the oldest or the newest instance of the sound, as specified by the When limit is reached and When priority is equal properties.
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When a sound is killed because of playback limit, it is not restarted when the play count falls below the limit. So, be careful with infinitely looping ambient sounds. |
Priority settings work together with the playback limit. Tweak priorities in the hierarchy to balance the limiting system. Sounds that should never be killed by the limiting system, like voice overs, background music, or looping ambient sounds, should have the highest priority. Furthermore, the effective priority can be affected by the distance between the sound and the listener.
The "under Volume Threshold" behavior has nothing to do with playback limits and priorities. It only tells what will be the sound's behavior when it is inaudible. To determine whether a sound is inaudible, Wwise only looks at the metadata volume, which is the resulting contribution of all volumes of the hierarchy, Busses, States, RTPC, and Set Voice Volume Actions. It never analyzes WAV data.