---
title: volume
framework: appkit
role: symbol
role_heading: Type Property
path: appkit/nsspeechsynthesizer/speechpropertykey/volume
---

# volume

Get or set the speech volume for a synthesizer.

## Declaration

```swift
static let volume: NSSpeechSynthesizer.SpeechPropertyKey
```

## Discussion

Discussion An NSNumber that specifies the synthesizer’s speech volume. Volumes are expressed in floating-point values ranging from 0.0 through 1.0. A value of 0.0 corresponds to silence, and a value of 1.0 corresponds to the maximum possible volume. Volume units lie on a scale that is linear with amplitude or voltage. A doubling of perceived loudness corresponds to a doubling of the volume. This property is used with setObject(_:forProperty:) and object(forProperty:).

## See Also

### Speech Property Keys

- [status](appkit/nsspeechsynthesizer/speechpropertykey/status.md)
- [errors](appkit/nsspeechsynthesizer/speechpropertykey/errors.md)
- [inputMode](appkit/nsspeechsynthesizer/speechpropertykey/inputmode.md)
- [characterMode](appkit/nsspeechsynthesizer/speechpropertykey/charactermode.md)
- [numberMode](appkit/nsspeechsynthesizer/speechpropertykey/numbermode.md)
- [rate](appkit/nsspeechsynthesizer/speechpropertykey/rate.md)
- [pitchBase](appkit/nsspeechsynthesizer/speechpropertykey/pitchbase.md)
- [pitchMod](appkit/nsspeechsynthesizer/speechpropertykey/pitchmod.md)
- [synthesizerInfo](appkit/nsspeechsynthesizer/speechpropertykey/synthesizerinfo.md)
- [recentSync](appkit/nsspeechsynthesizer/speechpropertykey/recentsync.md)
- [phonemeSymbols](appkit/nsspeechsynthesizer/speechpropertykey/phonemesymbols.md)
- [currentVoice](appkit/nsspeechsynthesizer/speechpropertykey/currentvoice.md)
- [commandDelimiter](appkit/nsspeechsynthesizer/speechpropertykey/commanddelimiter.md)
- [reset](appkit/nsspeechsynthesizer/speechpropertykey/reset.md)
- [outputToFileURL](appkit/nsspeechsynthesizer/speechpropertykey/outputtofileurl.md)