AircraftSoundManager

AircraftSoundManager inspector.

Purpose and Role

The AircraftSoundManager is the central audio control component for aircraft sound systems. It manages all AircraftSoundComponent instances attached to an aircraft and coordinates their audio output through a shared AudioMixer. The manager handles interior/exterior sound attenuation based on camera position and provides a unified audio mixing architecture for realistic sound behavior.

Architecture Overview

Component Hierarchy

The AircraftSoundManager operates within the aircraft's component structure:

AircraftController (with AircraftSoundManager attached)
├── AircraftSoundManager (central manager)
├── EngineRunningAircraftSoundComponent (engine sound)
├── WindAircraftSoundComponent (wind sound)
├── CrashAircraftSoundComponent (crash events)
└── (other sound components as needed)

Sound components can be attached to the same GameObject as the manager or to child objects. The manager automatically discovers and coordinates all child sound components.

Audio Mixing System

The manager uses an AudioMixer to:

  • Route all aircraft sounds through a consistent audio system
  • Apply global attenuation when camera is inside aircraft
  • Apply low-pass filtering to simulate cabin audio characteristics
  • Manage mixer group hierarchies for independent control

The default audio mixer (AircraftAudioMixer) includes:

  • Master group - Main output mixing point
  • Attenuation parameter - Controls volume reduction inside aircraft
  • LowPassFrequency parameter - Frequency cutoff for interior filtering
  • LowPassQ parameter - Filter resonance/width control

Component Lifecycle

Initialization

  1. Awake() - Manager initializes and loads default mixer if not assigned
  2. Reference Resolution - Caches AircraftController parent reference
  3. Default Assignment - Loads default AudioMixer from Resources if needed
  4. Event Registration - Subscribes to camera enter/exit vehicle events

Camera-Based Audio Control

The manager responds to camera position changes to create immersive audio:

  • Camera Inside Aircraft - Applies interior attenuation and low-pass filtering to simulate cabin audio characteristics
  • Camera Outside Aircraft - Removes attenuation and filtering for exterior audio perspective

This is driven by events from AircraftController:

  • onCameraEnterVehicle - Triggered when camera enters aircraft cockpit/cabin
  • onCameraExitVehicle - Triggered when camera exits aircraft

Configuration Properties

Audio Mixer

  • Mixer (AudioMixer) - The AudioMixer used to route all aircraft sounds. Leave null to load default mixer from Resources/NWH Aerodynamics/Defaults/Sound/AircraftAudioMixer.

The mixer must contain the following parameter groups and parameters:

  • Group name should match sound component mixer group names
  • Parameters: attenuation, lowPassFrequency, lowPassQ

Interior Audio Attenuation

  • Interior Attenuation (float, dB) - Volume reduction applied when camera is inside aircraft
    • Default: -7 dB (approximately 1/4 original volume)
    • Typical range: -6 to -12 dB
    • More negative values = quieter interior audio
    • Simulates sound dampening from cabin structure and headsets

Low-Pass Filter

The low-pass filter simulates audio characteristics of sound traveling through aircraft structure and cabin environment:

  • Low Pass Frequency (float, Hz) - Frequency threshold where attenuation begins

    • Default: 1600 Hz
    • Typical range: 1000-3000 Hz
    • Lower values = more muffled interior audio (removes high frequencies)
    • Simulates how aircraft cabin dampens higher frequencies

  • Low Pass Q (float, range 0.01-10) - Filter resonance/sharpness

    • Default: 1.0
    • Lower values = wider filter (gentler rolloff)
    • Higher values = narrower filter (sharper rolloff)
    • Controls how aggressively frequencies above cutoff are attenuated

Public API

Configuration Methods

  • SetDefaults() - Ensures an AudioMixer is assigned, loading default if necessary. Called automatically on Reset.

Automatic Management

The manager automatically:

  • Discovers all AircraftSoundComponent children
  • Registers sound components with the mixer
  • Applies attenuation changes when camera enters/exits vehicle
  • Updates low-pass filter parameters for interior audio simulation

No manual registration of sound components is required; they automatically report to the manager through the shared mixer.

Audio Mixer Configuration

Standard Setup

The default AudioMixer includes these groups and parameters:

Groups:

  • Master - Main output, all aircraft sounds routed here
  • Engine - Engine-related sounds
  • Wind - Wind/ambient sounds
  • Crash - Collision/crash sounds

Parameters:

  • attenuation - Master volume adjustment (dB)
  • lowPassFrequency - Interior filter frequency (Hz)
  • lowPassQ - Interior filter width

Custom Mixer Setup

To use a custom AudioMixer:

  1. Create AudioMixer with required groups and parameters
  2. Add parameter controls for:
    • attenuation (float, -80 to 0 dB range)
    • lowPassFrequency (float, 20-22000 Hz range)
    • lowPassQ (float, 0.1-10 range)
  3. Assign mixer to AircraftSoundManager in inspector
  4. Update sound component mixer group names to match

Sound Component Integration

Registration

Sound components automatically integrate with the manager through:

  • Parent hierarchy (must be child of AircraftController)
  • Shared mixer reference (loaded from manager)
  • Mixer group mapping (component requests group by name)

Communication

Components communicate with the manager indirectly:

  • All sounds route through assigned mixer
  • Manager updates mixer parameters based on camera position
  • Components observe parameter changes and adjust accordingly

Interior vs. Exterior Audio

Exterior (Default)

Normal audio playback
- No volume attenuation
- No low-pass filtering
- Full frequency range audible
- Natural aircraft sound characteristics

Example values set:

  • attenuation = 0 dB (original level)
  • lowPassFrequency = 22000 Hz (no filtering)
  • lowPassQ = 1.0

Interior

Muffled, cabin-like audio
- Reduced volume (typically -7 dB)
- High frequencies filtered out
- Simulates cabin structure audio dampening
- More realistic cockpit/cabin experience

Example values set:

  • attenuation = -7 dB (quieter)
  • lowPassFrequency = 1600 Hz (muffle effect)
  • lowPassQ = 1.0

Platform Considerations

  • Desktop - Can handle more simultaneous sounds (8-16+)
  • Mobile - More limited (4-8 depending on device)
  • VR - Consider spatial audio and positional aspects

Common Usage Patterns

Accessing the Manager

AircraftController aircraft = GetComponent<AircraftController>();
AircraftSoundManager soundManager = aircraft.GetComponent<AircraftSoundManager>();

// Access mixer for custom parameter control
AudioMixer mixer = soundManager.mixer;
mixer.SetFloat("customParameter", value);

Custom Interior/Exterior Settings

// Customize interior audio characteristics
soundManager.interiorAttenuation = -10f;      // Quieter (more dB reduction)
soundManager.lowPassFrequency = 1200f;        // More muffled
soundManager.lowPassQ = 0.8f;                 // Wider filter

// Apply immediately if already inside
soundManager.SetDefaults();

Camera Simulation

The manager responds to these AircraftController events:

AircraftController aircraft = GetComponent<AircraftController>();

// Simulate camera entering cockpit
aircraft.onCameraEnterVehicle.Invoke();

// Simulate camera exiting cockpit
aircraft.onCameraExitVehicle.Invoke();

Custom Mixer Control

// Access mixer and adjust parameters directly
mixer.GetFloat("attenuation", out float currentAttenuation);
mixer.SetFloat("attenuation", -5f);  // Increase volume slightly

// Query current settings
mixer.GetFloat("lowPassFrequency", out float frequency);

Troubleshooting

No Audio Heard

  1. Check AudioMixer is assigned (or default loads successfully)
  2. Verify sound components are children of AircraftController
  3. Check AudioListener exists in scene
  4. Verify AudioSource volume and mixer levels are not zero
  5. Test with simple AudioSource to verify audio system works

Sound Components Not Initializing

  1. Ensure AircraftSoundManager is on same GameObject as AircraftController
  2. Check AircraftController reference resolves correctly
  3. Verify AudioMixer has required groups
  4. Check console for error messages from Awake()

Interior Audio Muffling Not Working

  1. Verify onCameraEnterVehicle events fire correctly
  2. Check mixer parameters update (use Debug logs)
  3. Confirm AudioSource mixer group is set to correct group
  4. Verify low-pass filter is enabled in mixer DSP chain