3D spatial audio in Unity - Step-by-Step Execution

Concept Flow - 3D spatial audio

Start: Audio Source Setup

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Attach AudioSource Component

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Set AudioClip and Spatial Blend

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Place AudioSource in 3D Space

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Attach Audio Listener to Camera

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Play Audio

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Unity Calculates Audio Volume & Panning Based on Position

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User Hears 3D Spatial Sound

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End

The flow shows how Unity sets up and plays 3D spatial audio by positioning an audio source and listener, then calculating sound based on their positions.

Execution Sample

Unity

AudioSource audioSource = gameObject.AddComponent<AudioSource>();
audioSource.clip = myClip;
audioSource.spatialBlend = 1.0f; // 3D sound
audioSource.Play();

This code adds an AudioSource to a game object, sets a sound clip, enables 3D spatial audio, and plays the sound.

Execution Table

Step	Action	AudioSource Position	Listener Position	Spatial Blend	Sound Volume & Panning
1	Add AudioSource component	(0,0,0)	(0,0,0)	0 (default)	Sound is 2D, no spatial effect
2	Assign AudioClip	(0,0,0)	(0,0,0)	0	Ready to play, still 2D sound
3	Set spatialBlend = 1.0 (3D)	(0,0,0)	(0,0,0)	1.0	Sound will be spatialized
4	Move AudioSource to (5,0,0)	(5,0,0)	(0,0,0)	1.0	Sound volume decreases, panning to right ear
5	Play Audio	(5,0,0)	(0,0,0)	1.0	User hears sound from right side, volume based on distance
6	Move Listener to (5,0,0)	(5,0,0)	(5,0,0)	1.0	Sound volume max, centered in ears
7	Move AudioSource to (10,0,0)	(10,0,0)	(5,0,0)	1.0	Sound volume decreases, panning to right ear again
8	Stop Audio	(10,0,0)	(5,0,0)	1.0	Sound stops playing

💡 Audio stops playing, ending spatial audio simulation.

Variable Tracker

Variable	Start	After Step 3	After Step 4	After Step 5	After Step 6	After Step 7	Final
AudioSource Position	(0,0,0)	(0,0,0)	(5,0,0)	(5,0,0)	(5,0,0)	(10,0,0)	(10,0,0)
Listener Position	(0,0,0)	(0,0,0)	(0,0,0)	(0,0,0)	(5,0,0)	(5,0,0)	(5,0,0)
spatialBlend	0	1.0	1.0	1.0	1.0	1.0	1.0
Sound Playing	No	No	No	Yes	Yes	Yes	No

Key Moments - 3 Insights

Why does the sound volume decrease when the AudioSource moves away from the Listener?

Because Unity calculates volume based on distance between AudioSource and Listener, as shown in execution_table rows 4 and 7 where the AudioSource moves farther and volume decreases.

What does setting spatialBlend to 1.0 do?

It enables full 3D spatial audio, making sound position-dependent. This is shown in execution_table step 3 where spatialBlend changes from 0 to 1.0, enabling spatial effects.

Why does the sound become centered when the Listener moves to the AudioSource position?

Because the Listener and AudioSource are at the same position, so the sound is heard equally in both ears, as seen in execution_table step 6.

Visual Quiz - 3 Questions

Look at the execution_table at step 4. What happens to the sound volume and panning when the AudioSource moves to (5,0,0)?

A Volume decreases and sound pans to the right ear

B Volume increases and sound pans to the left ear

C Volume stays the same and sound is centered

D Sound stops playing

💡 Hint

Check the 'Sound Volume & Panning' column at step 4 in the execution_table.

At which step does the spatialBlend get set to enable 3D sound?

A Step 2

B Step 3

C Step 5

D Step 6

💡 Hint

Look at the 'spatialBlend' column in the variable_tracker and execution_table.

If the Listener moves to the AudioSource position, what happens to the sound according to the execution_table?

A Sound volume decreases and pans left

B Sound stops playing

C Sound volume maxes out and is centered

D Sound becomes 2D

💡 Hint

See step 6 in execution_table where Listener and AudioSource positions match.

Concept Snapshot

3D Spatial Audio in Unity:
- Add AudioSource component to GameObject
- Assign AudioClip to AudioSource
- Set spatialBlend = 1.0 for 3D sound
- Position AudioSource and AudioListener in scene
- Unity adjusts volume and panning based on distance and direction
- Play AudioSource to hear spatial sound

Full Transcript

This visual execution trace shows how 3D spatial audio works in Unity. First, an AudioSource component is added to a game object. Then, an audio clip is assigned to it. Setting spatialBlend to 1.0 enables 3D spatial sound. The AudioSource and AudioListener positions affect how the sound is heard. When the AudioSource moves away from the Listener, volume decreases and panning shifts. When both are at the same position, sound is centered and loudest. Playing and stopping audio shows the full cycle of spatial audio behavior.