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Chapter 9: Scene Sounds

Scene sounds add audio to individual scenes—background music, sound effects, voiceovers, and more. This chapter covers adding and configuring per-scene audio in FX Express.

Understanding Scene Sounds

Each scene can have multiple sounds that play sequentially:

  • Sounds play one after another in order
  • Each sound has individual volume and fade settings
  • Sounds automatically sync with scene timing

Scene sounds are separate from:

  • Video element audio: Audio embedded in video files
  • Voiceover: Global audio track spanning multiple scenes
  • Audio layers: Timeline layers with their own in-time, duration, and keyframable volume — see Chapter 22

Reach for a scene sound when audio belongs to the whole scene, and for an audio layer when it has to land on a beat. Both mix together, and a volume adjustment layer can duck scene sounds under narration.

Accessing Scene Sounds

To manage a scene’s sounds:

  1. Select the scene in the Scenes panel
  2. Click the speaker icon (🔊) in the scene toolbar
  3. The Scene Sounds dialog opens

Sound Types

FX Express supports four types of scene sounds:

Audio File

Upload audio files directly:

  • Supported formats: MP3, WAV, OGG, M4A
  • Stored locally for offline access
  • Best for: Music, sound effects, custom recordings

Pattern URL

Load audio from URLs with variable support:

  • Include {variables} in URLs
  • Dynamic audio based on data
  • Best for: Personalized content, dynamic audio libraries

Silence

Insert deliberate pauses:

  • Specify duration in seconds
  • Creates gaps between sounds
  • Best for: Pacing, dramatic pauses

Text-to-Speech (TTS)

Generate audio from text:

  • Multiple voice providers available
  • Supports variables for personalization
  • Best for: Dynamic narration, localization

Adding Sounds

Adding an Audio File

  1. Click + Add Sound in the dialog
  2. Select the File tab
  3. Click Upload or drag and drop an audio file
  4. The file uploads and appears in the sound list

Adding a Pattern URL

  1. Click + Add Sound
  2. Select the Pattern tab
  3. Enter the URL pattern (e.g., https://audio.example.com/{productId}.mp3)
  4. Toggle “Local file” if referencing local paths

Adding Silence

  1. Click + Add Sound
  2. Select the Silence tab
  3. Enter the duration in seconds
  4. Click Add

Adding TTS

  1. Click + Add Sound
  2. Select the TTS tab
  3. Select a provider (ElevenLabs, Google Cloud)
  4. Choose a voice
  5. Enter the text to speak (supports variables)
  6. Click Generate

Sound Settings

Each sound has individual settings for fine-tuned control:

Volume Percent

Base volume level:

  • 0%: Silent
  • 100%: Normal volume (default)
  • 200%: Doubled volume (may clip)

Gain (dB)

Additional volume adjustment in decibels:

  • -20 dB: Very quiet
  • 0 dB: No change (default)
  • +20 dB: Very loud (may clip)

Fade In

Gradual volume increase at the start:

  • Duration in milliseconds (0-10000)
  • 0 ms: Instant start (default)
  • 1000 ms: 1-second fade in

Fade Out

Gradual volume decrease at the end:

  • Duration in milliseconds (0-10000)
  • 0 ms: Instant end (default)
  • 1000 ms: 1-second fade out

Managing Sound Order

Sounds play sequentially in list order. To reorder:

  1. Click and drag a sound item
  2. Drop it in the new position
  3. The order updates immediately

Playback Sequence Example

Sound 1: Intro jingle (2s)
Sound 2: Silence (0.5s)
Sound 3: Voiceover (10s)
Sound 4: Background music (30s)

Sounds play one after another, not simultaneously.

Editing Sounds

To modify a sound’s settings:

  1. Find the sound in the list
  2. Click the edit icon (✏️)
  3. Adjust settings in the dialog
  4. Click Save

Editable Properties

  • Volume percent
  • Gain dB
  • Fade in duration
  • Fade out duration
  • Replace audio file (for File type)
  • Change URL pattern (for Pattern type)
  • Modify text/voice (for TTS type)

Removing Sounds

To delete a sound:

  1. Find the sound in the list
  2. Click the trash icon (🗑)
  3. Confirm deletion

Removed sounds cannot be recovered.

Sound Playback in Preview

Sounds play automatically during preview:

  • Sync with scene timing
  • Respect volume and fade settings
  • Use the mute toggle to silence all audio

Preview Controls

  • Play/Pause: Start or stop playback
  • Mute/Unmute: Toggle all audio
  • Seek: Jump to specific times

Audio Best Practices

Volume Levels

  • Keep consistent levels across scenes
  • Use -6 dB to -3 dB headroom to avoid clipping
  • Test with headphones for clarity

Fades

  • Use fade in to avoid abrupt starts
  • Use fade out for smooth endings
  • 200-500ms fades are typically subtle
  • 1000ms+ fades are noticeable

File Optimization

  • Use compressed formats (MP3) for efficiency
  • Match sample rate to needs (44.1kHz typical)
  • Trim unnecessary silence from files

TTS Considerations

  • Test voices before final use
  • Variables must have values for preview
  • Consider pacing and natural breaks

Common Use Cases

Background Music

Type: Audio File
Volume: 30-50%
Fade In: 1000ms
Fade Out: 2000ms

Lower volume to not compete with speech.

Sound Effect

Type: Audio File
Volume: 100%
Fade In: 0
Fade Out: 0

Full volume for impact.

Narration

Type: TTS or Audio File
Volume: 100%
Fade In: 200ms
Fade Out: 200ms

Clear and prominent.

Ambient Sound

Type: Audio File (loop)
Volume: 20-30%
Fade In: 2000ms
Fade Out: 2000ms

Subtle background atmosphere.

Combining with Video Audio

When scenes contain video elements with audio:

Option 1: Mute Video

  • Mute the video element
  • Use scene sounds for all audio
  • Full control over audio mix

Option 2: Keep Video Audio

  • Leave video unmuted
  • Scene sounds play alongside
  • Balance volumes appropriately

Option 3: No Scene Sounds

  • Video audio plays naturally
  • No scene sounds needed
  • Simplest approach

Troubleshooting

Sound Not Playing

  • Check if preview is muted
  • Verify the sound file uploaded successfully
  • Check volume settings (not 0%)
  • Ensure scene is long enough for audio

Sound Too Quiet/Loud

  • Adjust Volume Percent
  • Fine-tune with Gain dB
  • Check source file levels
  • Test in preview

Fades Not Working

  • Check fade duration values
  • Ensure sound is long enough for fades
  • Preview to verify effect

TTS Not Generating

  • Check API credentials/connection
  • Verify text content
  • Try a different voice
  • Check provider status

Pattern URL Not Loading

  • Verify URL is accessible
  • Check variable values
  • Test URL directly in browser
  • Ensure CORS allows access

Audio Sync Issues

  • Check scene duration settings
  • Verify sound durations
  • Ensure sounds fit within scene
  • Test with simpler setup first

Audio File Formats

FormatQualitySizeCompatibility
MP3GoodSmallUniversal
WAVExcellentLargeUniversal
OGGGoodSmallMost browsers
M4A/AACExcellentMediumMost browsers

Recommendation: Use MP3 for best compatibility and reasonable quality.

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