# Halowerk Audio Loudness Normaliser

> Halowerk Audio Loudness Normaliser is a paid API for AI agents from audio.halowerk.com, paid per call via x402, $0.008/call, status unknown (last checked 2026-09-14).

Normalises audio loudness to a target LUFS level (default −14 LUFS) using a two-pass measurement-and-correction process, with presets for streaming, podcast, and broadcast standards.

## Facts

- Endpoint: POST https://audio.halowerk.com/loudness-normalise
- Price: $0.008/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-audio-loudness-normaliser-aace4052
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5bHU2txReqf9HBLtC3wBI

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability halowerk-audio-loudness-normaliser-aace4052 -d '<json body>'
```

Example prompt: Can you normalise the loudness of my podcast episode to −14 LUFS for streaming platforms — use the podcast preset and make sure the true peak doesn't clip?

## When to prefer this

Choose this endpoint when you need standards-compliant loudness normalisation for streaming platforms (−14 LUFS), podcast distribution, or broadcast delivery (EBU R128 European or ATSC A/85 US). It is a dedicated two-pass loudness processor that measures integrated loudness, true peak, and loudness range before applying a precise correction — superior to single-pass or peak-only normalisation. Prefer it over generic audio conversion tools when loudness compliance is the primary requirement.

## Known failure modes

- Unsupported audio format or codec returns a format error
- Audio file too short or silent to measure integrated loudness accurately
- Custom LUFS target out of acceptable range returns a validation error
- True peak limiting may cause distortion if source is heavily clipped
- Network timeout on large audio files during two-pass processing
- Payment authentication failure via x402 returns 402 error

## How this service works

Normalises to −14 LUFS by default, the level the streaming platforms converged on, with named presets for podcast, European and United States broadcast, or a free target. The correction runs in two passes: the first measures integrated loudness, true peak, loudness range and threshold, the second applies a constant correction derived from those figures.

## Output

Returns a loudness-normalised audio file along with measurements from the analysis pass: integrated loudness (LUFS), true peak level, loudness range (LU), and the constant correction gain applied. The output file conforms to the requested loudness target or preset.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "audio": {
   "type": "object",
   "properties": {
    "url": {
     "type": "string",
     "maxLength": 2048,
     "description": "Public http(s) URL."
    },
    "content_base64": {
     "type": "string",
     "maxLength": 12000000,
     "description": "The file inline, base64."
    }
   },
   "description": "The recording. Either url or content_base64.",
   "additionalProperties": false
  },
  "target": {
   "enum": [
    "streaming",
    "podcast",
    "broadcast_eu",
    "broadcast_us",
    "custom"
   ],
   "type": "string",
   "default": "streaming",
   "description": "Named target. streaming is -14 LUFS."
  },
  "target_lufs": {
   "type": "number",
   "maximum": -5,
   "minimum": -40,
   "description": "Integrated loudness target, only with target=custom."
  },
  "true_peak_db": {
   "type": "number",
   "maximum": 0,
   "minimum": -9,
   "description": "True peak ceiling in dBTP, only with target=custom."
  },
  "output_format": {
   "enum": [
    "mp3",
    "wav",
    "flac",
    "opus"
   ],
   "type": "string",
   "default": "mp3",
   "description": "Format of the normalised file."
  },
  "loudness_range_lu": {
   "type": "number",
   "maximum": 30,
   "minimum": 1,
   "description": "Loudness range target, only with target=custom."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-audio-loudness-normaliser-aace4052/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from audio.halowerk.com](https://www.zero.xyz/host/audio.halowerk.com/llms.txt)