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  "documentType" : "symbol",
  "framework" : "AppKit",
  "identifier" : "/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/pitchBase",
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  "role" : "Type Property",
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    "preciseIdentifier" : "c:@NSSpeechPitchBaseProperty"
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  "title" : "pitchBase"
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# pitchBase

Get or set a synthesizer’s baseline speech pitch.

```
static let pitchBase: NSSpeechSynthesizer.SpeechPropertyKey
```

## Discussion

An <doc://com.apple.documentation/documentation/Foundation/NSNumber> object that specifies the baseline speech pitch. Typical voice frequencies range from around 90 hertz for a low-pitched voice to perhaps 300 hertz for a high-pitched voice. These frequencies correspond to approximate pitch values in the ranges of 30.000 to 40.000 and 55.000 to 65.000, respectively.

This property is used with [`setObject(_:forProperty:)`](/documentation/AppKit/NSSpeechSynthesizer/setObject(_:forProperty:)) and [`object(forProperty:)`](/documentation/AppKit/NSSpeechSynthesizer/object(forProperty:)).

> Note:
> The change in speech pitch may not be noticeable until the next sentence or paragraph is spoken.

---

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