Audio in Unity

Adding Background Music and Sound Effects

Audio plays a vital role in enhancing immersion in your games. Unity supports multiple types of audio, including background music, sound effects, ambient sounds, and voiceovers.

• Background Music (BGM): Looped music that sets the mood.
• Sound Effects (SFX): Short sounds for interactions like footsteps, jumps, or explosions.

To add audio to your game:

1. Import audio files (WAV, MP3, or OGG) into your Unity project.
2. Drag the audio file into a GameObject and it will automatically create an AudioSource component.
3. Configure the AudioSource to loop for background music or play once for sound effects.

AudioSource and AudioListener Components

Unity uses two key components for playing and detecting audio:

• AudioSource: Plays an audio clip. It can loop, play on awake, or be triggered through scripts.
• AudioListener: Acts as the “ears” of the player. Usually attached to the Main Camera to capture all surrounding sounds.

Example: Playing Background Music

using UnityEngine;

public class MusicPlayer : MonoBehaviour
{
    public AudioSource bgMusic;

    void Start()
    {
        bgMusic.loop = true;
        bgMusic.Play();
    }
}
      

Attach this script to a GameObject with an AudioSource and assign your music clip to the AudioSource.

Playing Sounds on Events and Collisions

Unity allows you to trigger audio clips in response to in-game events, such as collisions, item pickups, or user input.

Example: Play Sound on Collision

using UnityEngine;

public class CollisionSound : MonoBehaviour
{
    public AudioSource collisionSound;

    void OnCollisionEnter(Collision collision)
    {
        collisionSound.Play();
    }
}
      

This simple setup is perfect for adding sound effects to objects like bouncing balls or hitting walls.

Example: Play Sound on Button Click

using UnityEngine;
using UnityEngine.UI;

public class ButtonSound : MonoBehaviour
{
    public Button myButton;
    public AudioSource clickSound;

    void Start()
    {
        myButton.onClick.AddListener(() => clickSound.Play());
    }
}
      

Managing Volume and Audio Mixing

Unity provides Audio Mixer assets to control volume levels, apply effects, and manage different sound categories such as Music, SFX, and UI sounds.

1. Create an Audio Mixer via Assets → Create → Audio Mixer.
2. Create separate Groups for music and sound effects.
3. Assign AudioSources to these groups through the Output property.

Example: Adjusting Volume in Script

using UnityEngine;
using UnityEngine.Audio;

public class VolumeController : MonoBehaviour
{
    public AudioMixer mixer;

    public void SetMusicVolume(float volume)
    {
        mixer.SetFloat("MusicVolume", Mathf.Log10(volume) * 20); // Convert 0-1 to decibels
    }
}
      

Connect this function to a UI Slider to allow the player to adjust music volume dynamically.

Bringing Audio to Life

By combining background music, dynamic sound effects, and proper audio mixing, you can create an immersive experience that reacts to the player’s actions. Audio is not just an accessory—it's a powerful storytelling tool in your Unity games.