We are excited to announce that ElevenLabs speech synthesis models now support the speed control parameter! Following the stability, similarity boost, and style parameters, this new feature gives you even more precise control over your speech synthesis output.
New Parameter: Speed Control
Parameter Name: speed
Valid Range: 0.7 - 1.2
Default Value: 1.0 (normal speed)
Speed Range Guide
| Value | Effect | Use Case |
|---|---|---|
| 0.7 | Slowest speed | Tutorials, listening practice, content requiring careful attention |
| 0.8-0.9 | Slower speed | Audiobooks, news broadcasting, formal occasions |
| 1.0 | Normal speed | Daily conversation, general use (default) |
| 1.1 | Faster speed | Quick updates, energetic content |
| 1.2 | Fastest speed | Efficient delivery, fast-paced scenarios |
How to Use
Control speech rate by adding the speed parameter when calling the TTS API:
{
"model": "eleven_turbo_v2_5",
"voice": "21m00Tcm4TlvDq8ikWAM",
"text": "This is a test message demonstrating the speed control feature.",
"speed": 0.8
}
Examples in Different Languages
English at normal speed (speed: 1.0):
The quick brown fox jumps over the lazy dog.
English at slower speed (speed: 0.8):
The quick brown fox jumps over the lazy dog.
Chinese at normal speed (speed: 1.0):
人工智能正在改变我们的生活方式。
Chinese at slower speed (speed: 0.8):
人工智能正在改变我们的生活方式。
Supported Models
The speed control parameter is available for the following ElevenLabs models:
eleven_multilingual_v2- Multilingual modeleleven_turbo_v2_5- Turbo modeleleven_flash_v2_5- Flash model
Combining with Other Parameters
ElevenLabs offers a complete set of voice control parameters that you can combine:
| Parameter | Range | Purpose |
|---|---|---|
speed |
0.7-1.2 | Control speech rate |
stability |
0.0-1.0 | Control voice stability |
similarity_boost |
0.0-1.0 | Enhance similarity to original voice |
style |
0.0-1.0 | Control style exaggeration |
Combined Usage Example
{
"model": "eleven_multilingual_v2",
"voice": "21m00Tcm4TlvDq8ikWAM",
"text": "Welcome to our speech synthesis service.",
"speed": 0.9,
"stability": 0.7,
"similarity_boost": 0.5,
"style": 0.3
}
Typical Use Cases
Education & Training
Use slower speeds (0.7-0.8) to give learners enough time to understand and take notes.
Audiobooks
Adjust speed based on content type: normal speed for novels, slightly slower for technical documents.
News & Updates
Use faster speeds (1.1-1.2) to deliver more information in limited time.
Game Voiceovers
Adjust speed based on character personality: faster for energetic characters, slower for calm ones.
Customer Service
Adjust based on scenario: normal speed for urgent issues, slightly slower for detailed explanations.
Important Notes
-
Range Limitation: ElevenLabs speed parameter range is 0.7-1.2. Values outside this range will be automatically adjusted to valid limits.
-
Unified API: If you're using the unified TTS interface with a 0.5-2.0 range, the system will automatically map values to ElevenLabs' valid range.
-
Quality Impact: Extreme speeds may slightly affect audio quality. For best results, we recommend staying within the 0.8-1.1 range.
Try the ElevenLabs speed control feature today and make your voice content more expressive!