Engine audio

•Before you start

Use a vehicle that drives. Stop Play Mode and select the vehicle root in the Hierarchy.

An engine sound uses layers. A layer is a recording of the engine at one speed. As the RPM changes, RCCP changes the pitch of the layers and fades between them.

1. Open the Audio module

CAUTION: If you already have custom engine sounds, do not click a preset button. A preset button replaces the full layer set.

1. On the vehicle root, find Presentation > Audio.
2. If the module is missing, add it with +. Then click the card to select it.
3. Find Engine sounds in the Audio Inspector.
4. If you need a new starting set, click Create 4 Engine Sounds (Default).

Check: the engine layer cards contain audio clips.

2. Listen before you edit

1. Click Play and click in the Game view.
2. Listen at idle, during acceleration, during gear changes and after you release the throttle.
3. In the Audio Inspector, open Live values and examine Blend running now.
4. Stop Play Mode before you make permanent changes.

Check: the sound stays audible through the RPM range of the engine. When you release the throttle, a coasting sound plays and no gap occurs.

If all vehicle sound is missing, examine the Game-view audio mute, the clips and the volume. Also examine any assigned Mixer group. Do these checks before you change the layer settings.

•Layer cards

In the standard four-layer set, the cards are Low, Med, High, Idle. Idle is the last card. Set each reference to match the recording on its card. Do not use the card order.

Figure 01Open full size ↗

Open the screenshot at full size. On the first card, 1 On / Off holds the recordings. 2 RPM sets the window. 3 Ref gives the RPM of the On recording. 4 Off Ref RPM can replace that value for coasting.

This crop shows the first two cards of the example vehicle, which has four layers. The values are not a tuning recipe for your recordings.

Equal Power sorts the layers by reference RPM. Each layer needs an On clip and a unique Ref above 1. If one layer has no On clip, or its Ref is missing or not unique, RCCP uses Legacy. Always examine Blend running now.

3. Add your own recordings

Use looping engine recordings made at a known, constant RPM.

1. On a layer, replace On and Off with the matching powered clip and coasting clip.
2. Enter the RPM of the recording in Ref.
3. If the Off clip has a different recording RPM, enter that RPM in Off Ref RPM. At zero, the Off clip uses Ref.
4. Do steps 1 to 3 again for the other layers.
5. Set Engine blend to Equal Power.
6. Read Engine Layer Validation before you test.

Check: no On clips are missing, no layer entries are empty and no references are the same. In Play Mode, Blend running now shows Equal power.

If you do not know the recording RPM, use the measurement procedure below. With an incorrect reference, two overlapping recordings can sound like two different engines.

4. Check the RPM windows, then listen again

In Equal Power, the RPM window also limits how far the pitch of a recording can follow the engine.

1. Compare the reference of each layer with its neighbors in RPM order.
2. Make the RPM window of each layer wide enough for the transition to those neighbors.
3. Make sure that the lowest layer and the highest layer cover the operating range of the engine.
4. Test idle, acceleration through the full range, and a long coast back down.
5. Stop Play Mode and save the settings that work.

Check: the transitions cause no constant wrong note, no sudden silence and no unexpected volume change.

Pitch does not tune Equal Power. That mode calculates the pitch limits from the RPM window and the reference. Legacy uses Pitch.

•Optional: measure a recording's RPM

On each layer:

1. Click Measure. The tool analyzes the two assigned clips.
2. Read the confidence result and Details.
3. If the result is correct, click Apply.
4. Listen through the full operating range to confirm the result.

Measure needs an uncompressed .wav source. For other formats, use a known recording RPM or get a correct source recording.

Seed Reference RPMs From Legacy Ranges and Apply Seeds To All Layers calculate estimates from an old setup. Use them as start values only. Then measure and listen.

The engine sounds like two engines

Two audible recordings can give different RPM values. Do these checks:

• Examine if each Ref matches its own recording.
• Examine if the coasting clip needs a separate Off Ref RPM.
• Examine if an RPM window stops the pitch movement too early.
• Examine if Blend running now shows Legacy.

More volume or more layers do not correct an incorrect reference.

•Optional: the default four-layer set

The default button creates these reference values and windows for the included recordings. Use them as an example of windows that match the neighboring references. Do not use them as references for different clips.

The Idle layer uses the same recording for On and Off. The on = off badge shows this shared clip. The redline badge shows the layer with the highest RPM-window limit.

Smaller preset buttons are available for fewer recordings. These buttons also replace the full set.

•The validator

Engine Layer Validation updates while you edit.

Pitch-stretch warnings are guidance about sound quality only. Always listen. A validator without messages does not prove that the engine sounds correct.

•Optional: choose how the engine reacts to load

Load source controls the transition between On and Off:

Torque blend sets the mix of the two. Compare the sound in gear under power and while coasting before you decide.

Backfires that use the engine-braking signal also need engine braking enabled. For exhaust effects, refer to Surfaces and Effects.

•Other sounds and volume

Other sounds contains effect blocks, for example starter, gear change, crash, wind and tire sounds. Each block has its own clips and audio settings.

An assigned Mixer group sends the vehicle audio through a Unity audio mixer. You can then control vehicle volume and effects together.

Sound groups

The RCCP mixer has four groups under Master, one for each type of sound. If the Mixer group of a vehicle is the Audio mixer in RCCP Settings, each sound plays through its group:

The volume of each group is an exposed mixer parameter: RCCP_EngineVolume, RCCP_TiresVolume, RCCP_ImpactsVolume and RCCP_OtherVolume. In a script, RCCP.SetAudioVolume sets the volume of one group. Refer to API Reference. The Master volume, the slow-motion pitch and the pause apply to all four groups.

If the Mixer group of a vehicle is a different group, all sounds of the vehicle play through that group. The four group fields in RCCP Settings can also point to groups in your own mixer. Those sounds then do not go through the RCCP mixer and do not follow its pitch and volume.

An older RCCP Settings asset can have empty sound-group fields. If so, do the check below.

Check: select RCCP Settings and open Resources > Sound effects. Engine group, Tires group, Impacts group and Other group point to the four groups of the RCCP mixer. If one field is empty, click Use RCCP default groups. This button appears only while Audio mixer is assigned.

Audio and time scale

RCCP audio follows the time scale of the game through the mixer that RCCP Settings assigns. At time scale 0, the audio is silent. Examples are a paused replay, photo mode and your own pause menu. In slow motion, pitch and volume decrease. When time runs faster than 1x, pitch increases. While a replay rewinds, the audio is muted.

If the audio must ignore the time scale, clear Follow the time scale under Resources > Sound effects > Time scale in RCCP Settings. While Follow the time scale is on, four more settings appear: Lowest slow-motion pitch, Highest fast-forward pitch, Slow-motion volume drop and Mute while rewinding.

To keep a music source playing during a pause, use a script to set AudioSource.ignoreListenerPause to true on that source. The Audio Source Inspector has no checkbox for this property.

Check: open a replay and pause it. The engine becomes silent. At 0.5x, the engine plays lower and more quietly. When you exit the replay, the mixer goes back to its authored values.

For quiet crashes, refer to Tuning Recipes. The unit of Full-volume crash changes when Crash volume by mass changes. Before you adjust Full-volume crash, read the unit warning in the Inspector.

•Audio troubleshooting

•Read next

• How the Car Drives — engine RPM and shifting.
• Tuning Recipes — measured audio examples.
• Field Reference — detailed audio settings.

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