> ## Documentation Index
> Fetch the complete documentation index at: https://docs.modulate.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Audio Event Detection

> Audio event detection API — score an audio file against a fixed set of non-speech sound events in a single synchronous HTTP POST.

Audio Event Detection scores an audio file against a fixed set of non-speech sound events: instruments, human vocalizations such as laughter and coughing, and environmental noises such as a knock or a gunshot. It returns a probability for every supported event on every call, plus the duration of the processed audio. It is a pure classification endpoint, producing no transcript, diarization, or PII/PHI tagging.

|                   | Batch                                                              |
| ----------------- | ------------------------------------------------------------------ |
| **Use case**      | Score an audio file against a fixed set of non-speech sound events |
| **Protocol**      | HTTP POST                                                          |
| **Max file size** | 100 MB                                                             |
| **Output**        | A probability per event, plus `duration_ms`                        |
| **Options**       | None. Only `upload_file` is accepted                               |

`probs` carries 42 keys on every response. `cry` is an independent probability. The other 41 are drawn from a single shared distribution that sums to 1 across those keys, so they rank the most prominent event rather than reporting independent detections. See [Audio Event Detection](/get-started/audio-event-detection) for how to read the two kinds of value.

For a side-by-side comparison with the other Modulate capabilities, see [Which API should I use?](/guides/which-api).

## Authentication

Uses the `X-API-Key` header. See [Authentication and rate limits](/guides/authentication).