Qwen Audio 3.1 TTS Plus vs StepAudio 3 TTS

Qwen Audio 3.1 TTS Plus vs StepAudio 3 TTS at a glance

Qwen Audio 3.1 TTS Plus from Alibaba Cloud and StepAudio 3 TTS from StepFun are both in the Audio Generation category, available through the EmpirioLabs API.

Key differences

• Qwen Audio 3.1 TTS Plus is the newer release (Oct 21, 2026); StepAudio 3 TTS was released on Sep 9, 2026.
• Capabilities listed only for Qwen Audio 3.1 TTS Plus: expressive prosody, emotion control, voice tags, streaming, realtime, voice cloning.
• Capabilities listed only for StepAudio 3 TTS: contextual tts, voice control.
• StepAudio 3 TTS lists the lower rate for Synthesis (per 10,000 characters).

Qwen Audio 3.1 TTS Plus vs StepAudio 3 TTS: specs

Qwen Audio 3.1 TTS Plus vs StepAudio 3 TTS: API pricing

Live rates from the EmpirioLabs catalog for both models. Each rate card always matches what the API charges.

Qwen Audio 3.1 TTS Plus vs StepAudio 3 TTS: API parameters

Request parameters each model lists on EmpirioLabs, with the allowed values or range where one applies. A dash marks a parameter the model does not list.

Qwen Audio 3.1 TTS Plus vs StepAudio 3 TTS: limits and notes

Qwen Audio 3.1 TTS Plus

Voices

• 4 voices that read Chinese, English, and other languages: longanlingxin_v3.1, longanhuan_v3.1, and longanfengyue_v3.1 are female, and xunanchuan_v3.1 is male.
• Every voice id ends in _v3.1, for example longanlingxin_v3.1.

Custom voices

• Set voice to custom and pass voice_audio_url, an https URL to 10 to 20 seconds of clear speech from one speaker.
• WAV, MP3, M4A, OGG, WEBM and FLAC are accepted, up to 15 MB. Record in a quiet room, without music or other voices.
• The response includes voice_id and voice_id_expires_at. Pass the voice_id as voice to reuse the voice for 7 days, on POST /v1/audio/speech, POST /v1/audio/speech:stream or the realtime socket, where session.update takes the same fields and session.updated returns the voice_id. Only the account that created it can use it, on this model only.
• Each account can hold 10 custom voices on this model at a time.
• GET /v1/voices?model=qwen-audio-3-1-tts-plus lists the model's voices, including your custom voices with their ids. Add type=custom to list custom voices alone.
• DELETE /v1/voices/{voice_id}?model=qwen-audio-3-1-tts-plus deletes a custom voice, which frees its place at once.
• In the Playground, set Voice to Custom to use a saved voice again, copy its id, or delete it.
• Creating, listing and deleting custom voices adds no charge.

Delivery direction

• instruction sets emotion, tone, character, pace, and speaking style in natural language, up to 1,000 characters.
• Inline tags inside the text change the delivery from that point, for example [excited] or [whispers], or add a one-time sound such as [laughing] or [sighing]. The full list of tags is on the input parameter.
• SSML input is not supported.

Input limits

• Up to 10,000 characters per request.
• language_hints biases pronunciation for mixed-language text.

Output

• MP3, WAV, PCM, or Opus at 8,000 to 48,000 Hz.
• POST /v1/audio/speech:stream sends audio chunks while the speech is generated.

Realtime

• WEBSOCKET /v1/realtime?model=qwen-audio-3-1-tts-plus takes text while it is still being written and returns audio as it is generated. Send input_text_buffer.append events, then input_text_buffer.commit, or session.finish to end the session.
• Audio arrives in response.audio.delta events: 16-bit PCM at 24,000 Hz by default, or MP3 or Opus. Set the voice, instruction, format and other options with session.update; a change applies from the next segment.
• Text is spoken in segments that end at sentence boundaries, and each segment ends with a response.done event carrying its usage.

Billing

• Billed per character of the input text. A Chinese character counts as two characters, and inline tags count as characters. The instruction is not billed.
• On the realtime socket each segment is billed for its own characters.

StepAudio 3 TTS

Maximum input is 1,000 characters. Content in parentheses is treated as delivery direction and is not spoken. Use instruction for global emotion or style guidance, up to 500 characters. Twelve system voices are available. Recognized languages are Chinese, English, Japanese, Korean, French, and Spanish, with languages other than Chinese and English in preview. Output formats are mp3, wav, flac, opus, and pcm at 8000, 16000, 22050, or 24000 Hz. Wav is returned as a complete file rather than streamed. This model does not support voice_label.

How to call Qwen Audio 3.1 TTS Plus and StepAudio 3 TTS

Qwen Audio 3.1 TTS Plus serves speech through POST /v1/audio/speech and returns playable audio. Send the text to speak as input with the model id qwen-audio-3-1-tts-plus. Both models are called through the same endpoint. Set model to qwen-audio-3-1-tts-plus or stepaudio-3-tts. Get an API key from the EmpirioLabs dashboard.

curl https://api.empiriolabs.ai/v1/audio/speech \
  -H "Authorization: Bearer $EMPIRIOLABS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "qwen-audio-3-1-tts-plus",
    "input": "Welcome to EmpirioLabs. Your build just finished."
  }' \
  --output speech.mp3

Qwen Audio 3.1 TTS Plus vs StepAudio 3 TTS: tests and guides

Prompt tests and comparison runs that cover both models.

Guides Qwen Audio 3.1 TTS Plus vs Qwen Audio 3.1 TTS vs Gemini 2.5 Pro TTS vs StepAudio 3 TTS: one narration We gave Qwen Audio 3.1 TTS Plus, Qwen Audio 3.1 TTS, Gemini 2.5 Pro TTS and StepAudio 3 TTS the same narration and...

Qwen Audio 3.1 TTS Plus vs StepAudio 3 TTS: common questions

What is the difference between Qwen Audio 3.1 TTS Plus and StepAudio 3 TTS?

Qwen Audio 3.1 TTS Plus is the newer release (Oct 21, 2026); StepAudio 3 TTS was released on Sep 9, 2026. Capabilities listed only for Qwen Audio 3.1 TTS Plus: expressive prosody, emotion control, voice tags, streaming, realtime, voice cloning. Capabilities listed only for StepAudio 3 TTS: contextual tts, voice control. The specs, rate cards, and parameters on this page come from the live EmpirioLabs catalog.

Which is newer, Qwen Audio 3.1 TTS Plus or StepAudio 3 TTS?

Qwen Audio 3.1 TTS Plus is the newer release (Oct 21, 2026); StepAudio 3 TTS was released on Sep 9, 2026.

Which has the lower rate, Qwen Audio 3.1 TTS Plus or StepAudio 3 TTS?

StepAudio 3 TTS lists the lower rate for Synthesis (per 10,000 characters). Both live rate cards are on this page and always match what the API charges.

Can I switch between Qwen Audio 3.1 TTS Plus and StepAudio 3 TTS without rebuilding my integration?

Yes. Both models use POST /v1/audio/speech with the same EmpirioLabs API key, so most integrations switch by changing the model value. Check the parameters table on this page first if you rely on a model-specific parameter.