MetaSounds Quick Start

MetaSound is a high-performance audio system that provides audio designers with complete control over a Digital Signal Processing (DSP) graph to generate sound sources.

In this guide, you will learn how to create two gameplay-driven MetaSound Sources: a bomb sound effect and ambient wind.

Prerequisites

Before creating your first MetaSounds with this guide, you must create a new First Person Template project with Starter Content.

1 - Create the Bomb MetaSound

Though the rifle plays a sound when fired, the projectile is silent. Using MetaSound, you will create a bomb sound effect to be used by the projectile.

1A - Create the MetaSound Source

Because this will be a sound source within 3D space, start by creating a MetaSound Source with an attached Sound Attenuation Asset.

1. Create a MetaSound Source.

   1. In the Content Browser, click the Add button.

   2. Select Audio > MetaSound Source.

   3. Give the newly created Asset a name (such as MSS_Bomb).

2. Double-click the MetaSound to open the MetaSound Editor.

3. Set the Attenuation Settings to spatialize and attenuate the MetaSound based on its position relative to the listener.

   1. Click the Source button on the MetaSound Editor Toolbar.

   2. In the Details panel, click the dropdown next to Attenuation > Attenuation Settings.

   3. Select Sound Attenuation under the Create New Asset heading.

   4. Give the newly created Asset a name (such as SA_Bomb), then save it.

1B - Build the MetaSound Graph

Click image for full size.

Build the MetaSound Graph that controls how your MetaSound Source sounds. Follow the instructions below to create the graph shown above.

1. Find the On Play Input node and drag off of the pin into an empty space. Enter "Wave Player (Mono)" into the node search to create a connected node. You can move the node around the graph by dragging it.

2. On the Wave Player (Mono) node:

   1. Click the Wave Asset dropdown and select the Fire_Sparks01 Sound Wave.

   2. Enable Loop.

   3. Drag off the Out Mono pin and create a Mono Mixer (2).

   4. Drag off the Stop pin and create another Wave Player (Mono).

3. On the new Wave Player (Mono) node:

   1. Connect the On Finished pin to the On Finished Output node.

   2. Connect the Out Mono pin to the In 1 pin on the Mono Mixer (2).

   3. Drag off the Play pin and create a Random Get (WaveAsset:Array) node.

   4. Connect the Wave Asset pin to the Value pin on the Random Get (WaveAsset:Array) node.

4. On the Random Get (WaveAsset:Array) node:

   1. Drag off the Next pin and select Promote to Graph Input. This will create a Trigger Input node named Next.

   2. Drag off the In Array pin and select Promote to Graph Variable. This will create a WaveAsset:Array Variable node named In Array.

5. On the Mono Mixer (2):

   1. Enter 2.0 for Gain 1 (Lin).

   2. Connect the Out pin to the Out Mono Output node.

1C - Adjust the Explosion Wave Player Inputs

Adjust the Next Trigger and the In Array Variable.

1. Select the Next Trigger Input node.

2. In the Details panel, enter "Explode" into General > Input to rename it. This will be the name of the Trigger you will set to execute from Blueprint.

3. Select the In Array WaveAsset:Array Variable node.

4. In the Details panel, enter "ExplosionArray" into General > Variable to rename it.

5. Click the Add (+) button twice for Default Value > Default. These indices will hold Sound Wave references to be randomly selected from.

6. Click the Index[0] dropdown and select the Explosion01 Sound Wave.

7. Click the Index[1] dropdown and select the Explosion02 Sound Wave.

1D - Play the MetaSound

The MetaSound is now ready to play.

1. Click the Play button on the MetaSound Editor Toolbar to play the MetaSound. A spark sound will loop until the Explode Trigger executes, at which point a random explosion sound in the ExplosionArray will play before the MetaSound finishes. You can simulate the Explode Trigger execution by clicking the Execute (Down Arrow) button on the top-right corner of the Trigger Input node while the MetaSound is playing.

2. Save the MetaSound Source and close the MetaSound Editor.

2 - Add Bomb Logic to Blueprint

After designing the bomb sound, use the projectile's Blueprint to set up the runtime logic.

2A - Open the Projectile Blueprint

Open the pre-built projectile Blueprint.

1. In the Content Browser, navigate to All/Content/FirstPerson/Blueprints.

2. Double-click BP_FirstPersonProjectile to open it in the Blueprint Editor.

2B - Build the Blueprint Graph

Add to the existing Blueprint Graph to control the bomb MetaSound based on projectile lifecycle.

1. Right-click in an empty space and create an Event BeginPlay node.

2. Drag off the Event BeginPlay node and create a Spawn Sound Attached node.

3. On the Spawn Sound Attached node:

   1. Click the Sound dropdown and select your bomb MetaSound.

   2. Drag off the Attach to Component pin and create a Get Sphere node.

   3. Drag off the Return Value pin and create an Execute Trigger Parameter node.

   4. Hold Alt and click the Exec Output (>) pin to remove the connection between the Spawn Sound Attached and Execute Trigger Parameter nodes.

4. On the Execute Trigger Parameter node:

   1. Enter "Explode" for In Name.

   2. Drag off the Exec Input (>) pin and create an Event Destroyed node.

5. Save your changes to the Blueprint and close the Blueprint Editor.

2C - Test the Level

The Blueprint is now ready to test.

Click the Play button on the Level Editor Toolbar, pick up the rifle (by moving into it), and shoot it (by left-clicking) to verify your work.

The projectiles will produce spatialized, dynamic sounds. The spark sound loops until the projectile explodes by either making contact with a blue box or after a short time passes.

3 - Create the Wind MetaSound

Create a MetaSound for ambient wind to add some atmosphere to the scene.

3A- Create the MetaSound Source

Create another MetaSound Source Asset. This sound will not be spatialized within 3D space, so you don't have to attach a Sound Attenuation Asset.

1. Create a MetaSound Source.

   1. In the Content Browser, click the Add button.

   2. Select Audio > MetaSound Source.

   3. Give it a name (such as MSS_Wind).

2. Double-click the MetaSound to open the MetaSound Editor.

3B - Adjust the MetaSound Details

Before building the graph, adjust the default properties of the MetaSound to support persistent stereo audio.

1. In the Interfaces panel, click the Remove (Trash Bin) button next to the UE.Source.OneShot Interface entry. This will remove the On Finished Output node, which isn't used on persistent sounds such ambience or music.

2. Click the MetaSound button on the MetaSound Editor Toolbar.

3. In the Details panel, click the MetaSound > Output Format dropdown and select Stereo. This will replace the Out Mono Output node with Out Left and Out Right Output nodes.

3C - Build the MetaSound Graph

Click image for full size.

Build the MetaSound Graph that controls how your MetaSound Source sounds. Follow the instructions below to create the graph shown above.

1. Select the On Play Input node and delete it using the Delete key. It will not be needed in this graph.

2. Drag off the Out Left pin and create a Stereo Mixer (2) node.

3. Connect the Out Right pin to the Out R pin on the Stereo Mixer (2) node.

4. Right-click in an empty space and create a Noise node.

5. On the Noise node, drag off the Audio pin and create a One-Pole Low Pass Filter node.

6. Drag a selection box to select the Noise and One-Pole Low Pass Filter nodes.

7. Right-click either selected node and select Duplicate.

8. On the new Noise node, enter 1 for Seed. This will introduce variance in the noise generation.

9. On one of the One-Pole Low Pass Filter nodes, connect the Out pin to the In 0 L pin on the Stereo Mixer (2) node.

10. On the other One-Pole Low Pass Filter node, connect the Out pin to the In 0 R pin on the Stereo Mixer (2)node.

11. Right-click in an empty space and create an LFO node.

12. On the LFO node:

    1. Enter 0.1 for Frequency.

    2. Enter 20.0 for Min Value.

    3. Enter 80.0 for Max Value.

    4. Connect the Out pin to both of the Cutoff Frequency pins on the One-Pole Low Pass Filter nodes.

13. On the Stereo Mixer (2) node, drag off the Gain 0 (Lin) pin and create an InterpTo node.

14. On the InterpTo node:

    1. Enter 0.3 for Interp Time.

    2. Drag off the Target pin to create an Add (Float) node.

15. On the Add (Float) node:

    1. Enter 2.0 for Bottom Addend.

    2. Drag off the Top Addend pin and create a Multiply (Float) node.

16. On the Multiply (Float) node:

    1. Enter 3.0 for Bottom Multiplicand.

    2. Drag off the Top Multiplicand pin and select Promote to Graph Input. This will create a Float Input node named PrimaryOperand.

17. Select the PrimaryOperand Float Input node.

18. In the Details panel, enter "PawnSpeed" into General > Input to rename it.

3D - Play the MetaSound

The MetaSound is now ready to play.

1. Click the Play button on MetaSound Editor Toolbar to play the MetaSound. A dynamic wind-like sound will play in stereo until you click the Stop button. The signal gain is affected by the PawnSpeed Float Input node. You can simulate PawnSpeed values by clicking the Input Widget (Dial) on the node and dragging up or down.

2. Save the MetaSound Source and close the MetaSound Editor.

4 - Add Wind Logic to Blueprint

After designing the wind sound, use the Level Blueprint to set up the runtime logic.

4A - Open the Level Blueprint

To open the Level Blueprint, click the Blueprint button in the Level Editor Toolbar and select Open Level Blueprint.

4B - Build the Blueprint Graph

Click image for full size.

Build the Blueprint Graph to control the wind MetaSound based on Player movement.

1. Right-click in an empty space and create an Event BeginPlay node.

2. Drag off the Event BeginPlay node and create a Spawn Sound 2D node.

3. On the Spawn Sound 2D node:

   1. Click the Sound dropdown and select your wind MetaSound.

   2. Drag off the Return Value and create a Set Float Parameter node.

   3. Hold Alt and click the Exec Output (>) pin to remove the connection between the Spawn Sound 2D and Set Float Parameter nodes.

4. On the Set Float Parameter node:

   1. Enter "PawnSpeed" for In Name.

   2. Drag off the Exec Input (>) pin and create an Event Tick node.

5. Right-click in an empty space and create a Get Player Pawn node.

6. On the Get Player Pawn node, drag off the Return Value pin and create a Get Velocity node.

7. On the Get Velocity node, drag off the Return Value pin and create a Vector Length node.

8. On the Vector Length node, drag off the Return Value pin and create a Map Range Clamped node.

9. On the Map Range Clamped node:

   1. Enter 200.0 for In Range A.

   2. Enter 1000.0 for In Range B.

   3. Enter 1.0 for Out Range B.

   4. Connect the Return Value pin to the In Float pin on the Set Float Parameter node.

10. Save your changes to the Blueprint and close the Blueprint Editor.

4C - Test the Level

The Blueprint is ready to test.

Click the Play button on the Level Editor Toolbar and move around to verify your work.

The wind sound will play at a low volume when idle and grow louder as your velocity increases.

5 - On Your Own!

Now that you've finished creating two basic MetaSounds, consider taking this project even further. Below are some suggestions you can explore on your own:

• Alter your MetaSounds with some additional nodes. See the MetaSounds Reference Guide for information on the node library and other MetaSound features.

• Replace the default rifle firing sound with a MetaSound. Consider altering the sound dynamically based on the rate of fire, shot angle, or other variables.

• Add MetaSounds for player actions such as walking, jumping, and item pickup.

• Improve on the simple wind implementation you created with this guide. See the Lyra Sample Game project for an example of an advanced implementation that supports additional features, such as panning and environment response.