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# kAudioUnitProperty_TailTime

A read-only `Float64` value valid on the audio unit global scope.

```
var kAudioUnitProperty_TailTime: AudioUnitPropertyID { get }
```

## Discussion

Indicates a time estimate, in seconds, between the last valid input being received by an audio unit and the audio unit’s output becoming silent. For example, a reverb unit’s tail time estimates the “decay” time. The tail time value is usually a conservative estimate that you can depend on.

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