---
title: "Audio.Directivity.beam(focus:)"
framework: realitykit
role: symbol
role_heading: Case
path: "realitykit/audio/directivity/beam(focus:)"
---

# Audio.Directivity.beam(focus:)

A parametric frequency-dependent radiation pattern, where the focus determines the width of a beam.

## Declaration

```swift
case beam(focus: Double)
```

## Discussion

Discussion The focus parameter is in the range 0...1 where 0 is the default. The default .beam(focus: 0) projects sound of all frequencies evenly in all directions, where the rotation of the spatial audio source has no impact on the tonality of the sound. A focus of 0 is commonly referred to as “omnidirectional”. Increasing the focus parameter up to 1 will constrain the projection to increasingly narrow beam patterns, with high frequencies being more directional than low frequencies. A spatial audio source with a non-zero focus will sound “darker” when auditioning the source from the rear.