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 # sound:compute loudness ISO 532-1 (one-third-octave input)

 Last update: 31.07.2026 

**Version: 0.0.0**

## Description

Compute loudness according to the ISO532-1 standard for stationary sounds, using one-third-octave-band levels as input.

## Inputs

InputNameExpected type(s)Description**Pin 0**   
Requiredinput\_levels[`field`](../../core-concepts/dpf-types.md#field)Input one-third-octave-band levels in dB SPL on which to compute loudness. Exactly 28 band levels must be provided.  
  
Considered one-third-octave bands have the following central frequencies:  
  
**Pin 1**field\_type[`string`](../../core-concepts/dpf-types.md#standard-types)Field type associated with the recording conditions.  
  
Supported values:  
  
\* Free  
\* Diffuse  
  
Default: Free## Outputs

OutputNameExpected type(s)Description**Pin 0**output\_loudness\_sone[`double`](../../core-concepts/dpf-types.md#standard-types)Loudness in sone.**Pin 1**output\_loudness\_phon[`double`](../../core-concepts/dpf-types.md#standard-types)Loudness level in phon.**Pin 2**output\_specific\_loudness[`field`](../../core-concepts/dpf-types.md#field)Specific loudness in sone/Bark, that is, the loudness values over Bark band indexes.## Configurations

NameExpected type(s)Default valueDescription**mutex**[`bool`](../../core-concepts/dpf-types.md#standard-types)falseIf this option is set to true, the shared memory is prevented from being simultaneously accessed by multiple threads.## Scripting

**Category**: sound

**Plugin**: sound

**Scripting name**: None

**Full name**: None

**Internal name**: compute\_loudness\_iso532\_1\_frequency\_input

**License**: avrxp\_snd\_level1

## Changelog

- Version 0.0.0: Initial release.