voice_settings is an object sent in the handshake frame to configure provider-specific parameters:
{
"text": " ",
"voice_settings": {
"voice_speed": 1.2
}
}
Telnyx Natural
| Parameter | Type | Default | Description |
|---|---|---|---|
voice_speed | float | 1.0 | Speech rate. Values > 1 are faster. |
Telnyx NaturalHD
| Parameter | Type | Default | Description |
|---|---|---|---|
voice_speed | float | 1.0 | Speech rate. Values > 1 are faster. |
Telnyx Ultra
Telnyx Ultra is REST-only — not available over WebSocket. These settings apply to the REST API.
| Parameter | Type | Default | Description |
|---|---|---|---|
voice_speed | float | 1.0 | Speech rate. Values > 1 are faster. |
language_boost | string | — | Target language |
volume | float | — | Volume level |
emotion | string | — | Emotion: neutral, happy, sad, angry, fearful, disgusted, surprised |
Telnyx Qwen3TTS
| Parameter | Type | Default | Description |
|---|---|---|---|
language_boost | string | "Auto" | Target language. Accepted: Auto, English, Chinese, French, German, Italian, Japanese, Korean, Portuguese, Russian, Spanish, or ISO codes (en, zh, etc.) |
Azure Speech
| Parameter | Type | Default | Description |
|---|---|---|---|
language_code | string | "en-US" | Language code |
text_type | string | "text" | Input type: text or ssml |
effect | string | — | Audio effect: eq_car or eq_telecomhp8k |
gender | string | — | Voice gender filter: Male or Female |
AWS Polly
| Parameter | Type | Default | Description |
|---|---|---|---|
language_code | string | — | BCP-47 language code |
output_format | string | — | Audio format override |
engine | string | "standard" | Polly engine: standard, neural, generative, long-form |
text_type | string | "text" | Input type: text or ssml |
lexicon_names | array | — | Pronunciation lexicon names |
Minimax
| Parameter | Type | Default | Description |
|---|---|---|---|
speed | float | — | Speech rate |
vol | float | — | Volume |
pitch | integer | — | Pitch adjustment |
language_boost | string | — | Language emphasis |
Rime
| Parameter | Type | Default | Description |
|---|---|---|---|
voice_speed | float | 1.0 | Speech rate. Above 1.0 = faster, below 1.0 = slower. |
sampling_rate | integer | 24000 | Output sample rate in Hz. |
response_format | string | "mp3" | Output format: mp3, pcm, or wav. |
Inworld
| Parameter | Type | Default | Description |
|---|---|---|---|
language_code | string | — | Language code |
delivery_mode | string | — | STABLE, BALANCED, or CREATIVE. Only supported by inworld-tts-2. |
Fish Audio
| Parameter | Type | Default | Description |
|---|---|---|---|
format | string | "pcm" | mp3, wav, pcm, opus |
sample_rate | integer | 24000 | Valid values depend on format: pcm/wav — 8000, 16000, 24000, 32000, 44100; mp3 — 32000, 44100; opus — 48000 |