Text-to-Speech Configuration

Text-to-Speech (TTS) converts your bot's text responses into natural-sounding speech. Configure TTS settings in the Text-to-Speech tab of the Phone Channel.

Creating a TTS Provider

Before configuring TTS in the phone channel, you need to create a TTS provider:

1. Navigate to Bot > Providers
2. Click Create
3. Select Text-to-Speech as the Provider type
4. Choose your provider (Google, Azure, ElevenLabs, or botario)
5. Enter your credentials and configuration
6. Click Create

Available TTS Providers

Provider	Description
Google Text-to-Speech	High-quality voices with gender selection
Azure Speech Services TTS	Enterprise TTS with extensive voice library and pitch control
ElevenLabs	AI-powered voices with voice cloning and emotional control
botario	AI-powered Custom or self-hosted voices

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Phone Channel TTS Settings

After creating a provider, configure it in the Phone Channel:

Selecting a Provider

In the Text-to-Speech tab, select your TTS provider from the dropdown. Only providers that are:

1. Created in Bot > Providers with type "Text-to-Speech"
2. Enabled for this bot in Bot Settings

will appear in the list.

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Provider-Specific Configuration

Different providers offer different configuration options. The phone channel allows you to override provider defaults on a per-bot basis.

botario TTS

Setting	Description
Voice Override	Override the default voice
Language Override	Override the default language code
Speaking Rate Override	(coming soon) Speech speed (0.25 to 4.0, where 1.0 is normal)
Pitch Override	(coming soon) Voice pitch adjustment (-20.0 to 20.0, where 0.0 is normal)

Google Text-to-Speech

Setting	Description
Voice Override	Override the default voice (e.g., de-DE-Chirp3-HD-Puck)
Gender Override	Voice gender: MALE, FEMALE, or NEUTRAL
Language Override	Override the default language code
Speaking Rate Override	Speech speed (0.25 to 2.0, where 1.0 is normal)

Note: Google TTS speaking rate range is 0.25-2.0, more limited than other providers.

Azure Speech Services TTS

Setting	Description
Voice Override	Override the default voice (e.g., de-DE-KatjaNeural)
Language Override	Override the default language code
Speaking Rate Override	Speech speed (0.25 to 4.0, where 1.0 is normal)
Pitch Override	Voice pitch adjustment (-20.0 to 20.0, where 0.0 is normal)
Region Override	Azure region for TTS service

ElevenLabs

Setting	Description
Voice Override	Override the default voice ID
Speaking Rate Override	Speech speed (0.7 to 1.2, where 1.0 is normal)
Pitch Override	Voice pitch adjustment (-20.0 to 20.0)
Similarity Boost Override	Voice consistency (0.0 to 1.0) - higher values sound more like the original voice
Stability Override	Voice stability (0.0 to 1.0) - higher values are more consistent, lower values more expressive
Model Override	ElevenLabs model (e.g., eleven_turbo_v2_5)

ElevenLabs Settings Explained

Similarity Boost (0.0 - 1.0):

• Higher values make the voice sound more like the original voice sample
• Lower values allow more variation
• Default: 0.7

Stability (0.0 - 1.0):

• Higher values produce more consistent, predictable speech
• Lower values produce more expressive, dynamic speech
• Default: 0.7
• For professional/formal contexts, use higher stability (0.7-0.9)
• For casual/emotional contexts, use lower stability (0.3-0.6)

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Speaking Rate Ranges

Different providers have different speaking rate ranges:

Provider	Min	Max	Normal
Google TTS	0.25	2.0	1.0
Azure TTS	0.25	4.0	1.0
ElevenLabs	0.7	1.2	1.0
botario	0.25	4.0	1.0

Tip: For elderly callers or complex information, reduce speaking rate to 0.8-0.9. For quick confirmations, you can increase to 1.1-1.2.

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Effective Values

Each setting shows two values:

• Current value: What you've configured (or empty for provider default)
• Effective value: The actual value being used (your override or provider default)

The "Effective value" with "(provider default)" indicates the setting is using the provider's default configuration.

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Dynamic TTS Configuration

You can change TTS settings during a conversation using the tracker API:

from botario_gpt_events.api_config.tts_api_config import GoogleTTSConfigUpdatePayload

# Slow down for important information
tracker_api.update_tts_config(
    GoogleTTSConfigUpdatePayload(
        speaking_rate=0.85,
        gender="FEMALE"
    )
)

See Phone API Reference for complete documentation.

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Optimizing Voice Output

Text Normalization

For best TTS results, enable Text Normalization to ensure:

• Dates are spoken naturally ("January 15th" not "one five dot zero one")
• Phone numbers are spelled digit by digit
• Abbreviations are expanded or spelled appropriately
• Currency amounts are pronounced correctly

Voice Selection

When selecting voices:

• Neural voices (Azure, Google, botario) sound more natural
• Consider your audience's language and regional preferences
• Test different voices for brand fit

Performance Considerations

• ElevenLabs offers high quality but may have higher latency
• Azure and Google neural voices offer excellent quality with good performance
• For high-volume applications, test latency with your expected load

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Troubleshooting

Speech Sounds Robotic

• Try a different voice (neural voices sound more natural)
• Adjust stability settings (ElevenLabs)
• Enable Text Normalization

Speech Too Fast/Slow

• Adjust Speaking Rate Override
• Remember different providers have different ranges

Wrong Language/Accent

• Check Language Override setting
• Verify the voice supports your target language
• Some voices are multi-lingual, others are language-specific

Provider Sync Failed

• Check PhoneServer Providers for sync status
• Verify API credentials are correct
• Check provider URL and region settings

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Related Documentation

• Speech-to-Text Configuration - Configure voice input
• Text Normalization - Optimize text for speech
• PhoneServer Providers - Monitor provider sync
• Phone API Reference - Dynamic TTS configuration
• Bot Providers - Managing providers