<!--
{
  "availability" : [
    "iOS: 6.0.0 -",
    "iPadOS: 6.0.0 -",
    "macCatalyst: 13.1.0 -",
    "tvOS: 9.0.0 -",
    "visionOS: 1.0.0 -",
    "watchOS: 2.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "AVFAudio",
  "identifier" : "/documentation/AVFAudio/AVAudioSession/outputNumberOfChannels",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "AVFAudio"
    ],
    "preciseIdentifier" : "c:objc(cs)AVAudioSession(py)outputNumberOfChannels"
  },
  "title" : "outputNumberOfChannels"
}
-->

# outputNumberOfChannels

The number of audio output channels.

```
var outputNumberOfChannels: Int { get }
```

## Discussion

You can observe changes to the value of this property using key-value observice. For more information, see <doc://com.apple.documentation/documentation/Swift/using-key-value-observing-in-swift>.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)