🔊 Lesson 6.3: Adding Sound & Music

Sound is half the feel of a game. A cheerful ding when you collect a star, a gentle background loop — both are quick to add in Unity with the Audio Source component.

🎯 Learning Objectives

Understand Audio Source and Audio Clip
Play looping background music
Play a one-shot sound effect on an event (like collecting)
Know why the Main Camera usually holds an Audio Listener

Estimated Time: 35 minutes

In This Lesson

The Audio Pieces

Piece	What it is
Audio Clip	An imported sound file (.wav, .mp3, .ogg) — an asset in your Project.
Audio Source	A component that plays a clip from a GameObject.
Audio Listener	The "ears" — one lives on the Main Camera by default. Don't add extras.

💡 Import a sound by dragging an audio file into the Project panel. It becomes an Audio Clip you can drop into any Audio Source.

Background Music

Music is the simplest case — an Audio Source that plays on start and loops. No code needed:

Create an empty GameObject named Music.
Add Component ▸ Audio Source.
Drag your music clip into the AudioClip field.
Tick Play On Awake and Loop. Lower the Volume a little (music should sit under the action).

Press Play — music plays and repeats. That's it.

A Collect Sound Effect

Sound effects fire on an event, so we trigger them from code with PlayOneShot. Add an Audio Source to the GameManager (leave Play On Awake off), then:

using UnityEngine;
using TMPro;

public class GameManager : MonoBehaviour
{
    public TMP_Text scoreText;
    public AudioClip collectSound;   // drag a 'ding' clip here
    private AudioSource audioSource;
    private int score = 0;

    void Start()
    {
        audioSource = GetComponent<AudioSource>();
        UpdateScoreText();
    }

    public void AddPoint()
    {
        score++;
        UpdateScoreText();

        // play the collect sound once
        if (collectSound != null)
            audioSource.PlayOneShot(collectSound);
    }

    void UpdateScoreText()
    {
        scoreText.text = "Score: " + score;
    }
}

📖 Definition

PlayOneShot(clip): plays a clip once, layered over anything else the source is doing. Ideal for short effects like pickups and clicks — you can fire many rapidly without cutting each other off.

⚠️ No sound?

Check: the GameManager has an Audio Source component; the collectSound clip is assigned; your system volume isn't muted; and there's exactly one Audio Listener (on the Main Camera).

Getting Audio Clips

You need actual sound files. Good sources for free, licensed audio:

The Unity Asset Store (filter by free) has sound-effect and music packs.
Sites like freesound.org and opengameart.org offer free clips (always check the licence).
Short .wav files work great for effects; .ogg or .mp3 for longer music.

💡 Always check the licence before shipping a game with someone else's audio. "Free to download" isn't always "free to use in a released game" — look for CC0 or clearly permissive licences.

Hands-on Exercise

🏋️ Exercise: Ding!

Import a short "ding" sound and a looping music track (any free clips).
Set up looping background music on a Music object (Play On Awake + Loop).
Add an Audio Source to the GameManager and assign the ding to collectSound.
Play and collect stars — each one dings while the music loops underneath.

💡 Only music plays, no ding

The collectSound clip probably isn't assigned, or the GameManager has no Audio Source. Check both. Also confirm AddPoint() is actually being called (add a Debug.Log).

🎯 Quick Quiz

Question 1: Which method plays a short sound effect once, without interrupting other audio?

Question 2: For looping background music, which two Audio Source options do you tick?

Summary

🎉 Key Takeaways

An Audio Clip is the sound file; an Audio Source plays it; the Audio Listener (on the camera) hears it.
Background music = Audio Source with Play On Awake + Loop, no code.
Sound effects = audioSource.PlayOneShot(clip) fired from an event.
Use free, correctly-licensed clips; check the licence before releasing.

🚀 What's Next?

You now have every building block — movement, physics, pickups, UI, sound. Module 7 assembles them into a complete, playable mini-game.

🎉 Module 6 complete!

Your game looks and sounds alive. Time to put it all together.