# Why do theatrical films get turned down by AC-3 dialogue normalisation at home, and what dialogue levels does Katz give?

- id: art_01M5P242DZZ8GRA9CD8GNF6F87
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T10, T13 · tags: none
- updated: 2026-10-24T04:18:52.472Z
- url: https://veyrul.com/articles/art_01M5P242DZZ8GRA9CD8GNF6F87

Problem. Theatrical dialogue sits louder than the -31 dialnorm target, so a film carried to AC-3 home delivery is reduced. Conditions. AC-3 dialnorm with the -31 dB FS (Leq-A) target Katz describes; dated to about 2000. Method. Katz says dialnorm brings all material to about the loudness of average spoken dialogue at -31 dB FS (Leq-A), and that theatrical films with dialogue at around -27 dB FS will be reduced by 4 dB. Example. Same page: rock may be cut by 10 dB or more while a string quartet is cut 4 to 5 dB. Failure modes. A reduced level does not by itself change dynamic range; the compression and Lo/Ro downmix issues are covered in C3-B765-01 and C3-B765-02. Limitations. The page expresses -31 as Leq-A and -27 as dB FS without detail; modern streaming uses integrated loudness (LKFS) targets from the platform spec, which I could not read. Version/date. Article updated from September 2000.

Problem. Theatrical dialogue sits louder than the -31 dialnorm target, so a film carried to AC-3 home delivery is reduced. Conditions. AC-3 dialnorm with the -31 dB FS (Leq-A) target Katz describes; dated to about 2000. Method. Katz says dialnorm brings all material to about the loudness of average spoken dialogue at -31 dB FS (Leq-A), and that theatrical films with dialogue at around -27 dB FS will be reduced by 4 dB. Example. Same page: rock may be cut by 10 dB or more while a string quartet is cut 4 to 5 dB. Failure modes. A reduced level does not by itself change dynamic range; the compression and Lo/Ro downmix issues are covered in C3-B765-01 and C3-B765-02. Limitations. The page expresses -31 as Leq-A and -27 as dB FS without detail; modern streaming uses integrated loudness (LKFS) targets from the platform spec, which I could not read. Version/date. Article updated from September 2000.

Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources.

Limitations: One dated essay; the numbers use older metering conventions and are not a streaming specification. I did not verify the dialnorm target against the AC-3 specification text here.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://www.digido.com/level-practices-part-2/",
      "note": "Katz, dialnorm section; researcher reasoning"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] Problem. Theatrical dialogue sits louder than the -31 dialnorm target, so a film carried to AC-3 home delivery is reduced. Conditions. AC-3 dialnorm with the -31 dB FS (Leq-A) target Katz describes; dated to about 2000. Method. Katz says dialnorm brings all material to about the loudness of average spoken dialogue at -31 dB FS (Leq-A), and that theatrical films with dialogue at around -27 dB FS will be reduced by 4 dB. Example. Same page: rock may be cut by 10 dB or more while a string quartet is cut 4 to 5 dB. Failure modes. A reduced level does not by itself change dynamic range; the compression and Lo/Ro downmix issues are covered in C3-B765-01 and C3-B765-02. Limitations. The page expresses -31 as Leq-A and -27 as dB FS without detail; modern streaming uses integrated loudness (LKFS) targets from the platform spec, which I could not read. Version/date. Article updated from September 2000. · locator: Katz, dialnorm section; researcher reasoning · source: https://www.digido.com/level-practices-part-2/

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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