Fish Audio S2.1 Pro is Fish Audio's recommended production speech model for text-to-speech and voice cloning. Official materials describe improvements in quality, latency, and throughput compared with S2 Pro, making it suitable for applications that require natural voices and ongoing voiceover production. This platform explicitly selects this model through model: s2.1-pro, retaining the interfaces for text, voice references, output formats, and task callbacks.
Submit requests to the public API at api.acedata.cloud using the documented parameters, then use the results in your application.
Input parameters and result formats vary by service. Use the public API for this model and follow its guide for generation, task retrieval and editing operations.
Clarify the model, inputs and outputs, and invocation method before selecting a solution.
Capability descriptions combine public model materials and this platform's documentation; refer to the relevant API and pricing sections for actual parameters, outputs, and billing rules.
Learn about the voice tasks that s2.1-pro is suited to handle.
Officially, S2.1 Pro is positioned as the recommended production model, with stated improvements in quality, latency, and throughput compared with S2 Pro. During selection, verify these changes using your own scripts and voice samples; do not turn official directional descriptions into fixed latency or concurrency commitments.
You can use an existing voice through reference_id, or provide a reference recording and accurate verbatim transcript in a single request. Reusing voice materials helps compare new and old models, but generated results still need to be checked for tone, pronunciation, and character consistency.
Submit synthesis using text and format settings, then retrieve audio_url when complete. Long scripts can be configured with callback_url: save the task ID first, then receive the completed result; applications do not need to present a task still waiting as delivered audio.
Choose based on specific content and delivery method.
For frequently updated knowledge content, product explanations, or product tutorials, first select representative scripts for evaluation, then gradually migrate the production workflow. Save model and voice information to make it easier to identify settings when differences in delivery occur.
Convert navigation, explanations, and help text into playable audio, focusing on the clarity and waiting experience that real users hear. This endpoint delivers audio links; real-time conversational applications require separate design for playback and buffering.
Compare S2 Pro and S2.1 Pro using the same voice and text, checking proper nouns, long sentences, pauses, and the amount of post-processing required. Use small-batch listening tests to decide the scope of migration, avoiding direct bulk replacement of existing finished content.
Compare based on scripts, voices, and production costs.
This endpoint still defaults to s2-pro; to use S2.1 Pro, set model: s2.1-pro. Do not assume that a request without a specified model already uses it solely based on its official positioning as the “recommended production model.”
Official materials do not provide a fixed percentage improvement that can be promised for this page. Compare audio quality, task wait times, review, and revision costs before deciding whether to replace an existing workflow; S1 can also remain a candidate for stable long-form narration.
Listen to samples first, then expand to production content.
Clarify the purpose of the narration, proofread the script, and choose a saved voice or prepare a reference recording and transcript.
Explicitly specify s2.1-pro and use representative passages to confirm pronunciation, pacing, and output format.
Save settings and task IDs, retrieve the audio link after completion, then arrange playback, editing, or content delivery.
Understand the synthesis method and delivery scope.
Answers to common questions when using s2.1-pro.
Official information states that S2.1 Pro improves quality, latency, and throughput, and lists it as the recommended production model. No specific degree of improvement is promised here; migration should be evaluated using your own scripts, voices, and actual call results.
Specify s2.1-pro through the HTTP request header model. If not specified, the default is s2-pro; the voice reference_id belongs to voice selection and is configured separately from the synthesis model.
For recurring characters or serialized content, you can reuse a voice with reference_id; for one-off projects, you can provide recordings and transcripts with references. The two are mutually exclusive, and one-time cloning accepts only one reference sample.
prosody.speed=1.0 indicates the original speed, volume uses dB, and 0 means no change to volume. You can choose mp3, wav, or pcm; the latter two both use the WAV container, and MP3 bitrates can be 64, 128, or 192.
After setting callback_url, first save task_id and started_at, then wait for the completion callback; you can also query by task ID. Only after obtaining audio_url can you proceed to playback or editing.
Model information · Updated: 2026-10-01. For call parameters and billing rules, see the API and pricing sections.
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This is only a basic call example. See the full docs for more parameters and advanced usage.
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