# Stable Audio 3 Small SFX Base Audio to Audio > Stable Audio 3 Small SFX Base audio-to-audio is the foundational 459 million parameter checkpoint that transforms input audio into new sound-effect variations guided by text prompts. ## Overview - **Endpoint**: `https://fal.run/fal-ai/stable-audio-3/small/sfx/base/audio-to-audio` - **Model ID**: `fal-ai/stable-audio-3/small/sfx/base/audio-to-audio` - **Category**: audio-to-audio - **Kind**: inference **Tags**: sfx, sound-effects, style-transfer ## Pricing - **Price**: $0.0315 per audios For more details, see [fal.ai pricing](https://fal.ai/pricing). ## API Information This model can be used via our HTTP API or more conveniently via our client libraries. See the input and output schema below, as well as the usage examples. ### Input Schema The API accepts the following input parameters: - **`negative_prompt`** (`string`, _optional_): Text description of qualities to avoid in the output. Default value: `""` - Default: `""` - **`duration`** (`float`, _optional_): Duration of the generated audio in seconds. Default value: `30` - Default: `30` - Range: `1` to `120` - **`num_inference_steps`** (`integer`, _optional_): Number of sampling steps. Base (non-distilled) checkpoints typically need ~50 for good quality. Default value: `50` - Default: `50` - Range: `1` to `100` - **`guidance_scale`** (`float`, _optional_): Classifier-free guidance scale. Higher values follow the prompt more strictly; ~7.0 is a good starting point for base checkpoints. Default value: `7` - Default: `7` - Range: `0` to `25` - **`seed`** (`integer`, _optional_): Random seed for reproducible outputs. Omit for a random seed. - **`enable_prompt_expansion`** (`boolean`, _optional_): If True, the prompt will be expanded using an LLM for more detailed and higher quality results. - Default: `false` - **`enable_safety_checker`** (`boolean`, _optional_): Enable NSFW content safety checking. Default value: `true` - Default: `true` - **`sync_mode`** (`boolean`, _optional_): If True, the audio is returned inline as a data URI and the result is not saved to the request history. - Default: `false` - **`output_format`** (`OutputFormatEnum`, _optional_): Container format for the generated audio output. Default value: `"mp3"` - Default: `"mp3"` - Options: `"mp3"`, `"wav"`, `"flac"`, `"ogg"`, `"opus"`, `"m4a"`, `"aac"` - **`bitrate`** (`string`, _optional_): Audio bitrate for compressed output formats (e.g., mp3, aac, opus). Format e.g. '192k' or '320k'. Ignored for lossless formats (wav, flac). Default value: `"192k"` - Default: `"192k"` - **`prompt`** (`string`, _required_): Text description guiding how the source audio should be transformed. - Examples: "bossa nova bassline" - **`audio_url`** (`string`, _required_): Source audio to transform. - Examples: "https://storage.googleapis.com/falserverless/model_tests/diffrythm/rock_en.wav" - **`init_noise_level`** (`float`, _optional_): How much noise to add to the source audio. 1.0 fully replaces the audio with noise (pure generation); 0.1 keeps the source close to the input. 0.5 sits halfway between. Default value: `0.9` - Default: `0.9` - Range: `0` to `1` **Required Parameters Example**: ```json { "prompt": "bossa nova bassline", "audio_url": "https://storage.googleapis.com/falserverless/model_tests/diffrythm/rock_en.wav" } ``` **Full Example**: ```json { "duration": 30, "num_inference_steps": 50, "guidance_scale": 7, "enable_safety_checker": true, "output_format": "mp3", "bitrate": "192k", "prompt": "bossa nova bassline", "audio_url": "https://storage.googleapis.com/falserverless/model_tests/diffrythm/rock_en.wav", "init_noise_level": 0.9 } ``` ### Output Schema The API returns the following output format: - **`audio`** (`File`, _required_): The generated audio clip. - **`seed`** (`integer`, _required_): The random seed used for generation. - **`prompt`** (`string`, _required_): The prompt used for generation. **Example Response**: ```json { "audio": { "url": "", "content_type": "image/png", "file_name": "z9RV14K95DvU.png", "file_size": 4404019 }, "prompt": "" } ``` ## Usage Examples ### cURL ```bash curl --request POST \ --url https://fal.run/fal-ai/stable-audio-3/small/sfx/base/audio-to-audio \ --header "Authorization: Key $FAL_KEY" \ --header "Content-Type: application/json" \ --data '{ "prompt": "bossa nova bassline", "audio_url": "https://storage.googleapis.com/falserverless/model_tests/diffrythm/rock_en.wav" }' ``` ### Python Ensure you have the Python client installed: ```bash pip install fal-client ``` Then use the API client to make requests: ```python import fal_client def on_queue_update(update): if isinstance(update, fal_client.InProgress): for log in update.logs: print(log["message"]) result = fal_client.subscribe( "fal-ai/stable-audio-3/small/sfx/base/audio-to-audio", arguments={ "prompt": "bossa nova bassline", "audio_url": "https://storage.googleapis.com/falserverless/model_tests/diffrythm/rock_en.wav" }, with_logs=True, on_queue_update=on_queue_update, ) print(result) ``` ### JavaScript Ensure you have the JavaScript client installed: ```bash npm install --save @fal-ai/client ``` Then use the API client to make requests: ```javascript import { fal } from "@fal-ai/client"; const result = await fal.subscribe("fal-ai/stable-audio-3/small/sfx/base/audio-to-audio", { input: { prompt: "bossa nova bassline", audio_url: "https://storage.googleapis.com/falserverless/model_tests/diffrythm/rock_en.wav" }, logs: true, onQueueUpdate: (update) => { if (update.status === "IN_PROGRESS") { update.logs.map((log) => log.message).forEach(console.log); } }, }); console.log(result.data); console.log(result.requestId); ``` ## Additional Resources ### Documentation - [Model Playground](https://fal.ai/models/fal-ai/stable-audio-3/small/sfx/base/audio-to-audio) - [API Documentation](https://fal.ai/models/fal-ai/stable-audio-3/small/sfx/base/audio-to-audio/api) - [OpenAPI Schema](https://fal.ai/api/openapi/queue/openapi.json?endpoint_id=fal-ai/stable-audio-3/small/sfx/base/audio-to-audio) ### fal.ai Platform - [Platform Documentation](https://docs.fal.ai) - [Python Client](https://docs.fal.ai/clients/python) - [JavaScript Client](https://docs.fal.ai/clients/javascript)