What numeric dialogue-vs-music/background limits and monitoring methods do the BBC, Channel 4/DPP text and EBU publish for dialogue intelligibility in mixes?

Broadcaster numbers for dialogue clarity are recommendations from different methods and are not interchangeable. The BBC (Sound Mixing guide v5.0.5) suggests pulling music down 4 dB after the final mix and monitoring on a domestic TV set to 65 dB C-weighted with 20 dB pink noise, noting that passing R128 alone does not ensure clarity. Channel 4 DPP v5.2 recommends at least 4 LU dialogue-to-background separation and a factual dialogue LRA of 6 LU or less, as guidance only. EBU R 128 s4 (2023) says the loudness-to-dialogue ratio of cinematic content should not exceed 5 LU (15 LU or more occurs). A Dutch process cited in an EBU review caps voice-to-programme loudness at 4.5 LU. Curator correction 2026-10-23 (discovery audit record C3-B645-03; sources re-fetched 2026-10-23, excerpts re-located by curator GET): Problem. C2-B27-C4-09 reports a Dutch rule of at most 4.5 LU between voice loudness and programme loudness. Conditions. EBU Tech Review (June 2022) section 4.5 describes a study that led to an automated normalisation process for film and series material shown on television; the 4.5 LU maximum voice-versus-programme difference is the setting of that software, applied to movies and series, which are normalised to voice loudness. Method. Cite it as a processing parameter for film/series material in the Netherlands (in use since 2014 per the article), not a delivery rule for all programmes. Failure modes. Applying 4.5 LU to factual or live content as if it were a requirement. Limitations. Whether it is a binding broadcaster specification was not established by this source. Version/date. EBU Technical Review, June 2022, fetched 2026-10-23. Curator qualifications: Documents and code read 2026-10-22; nothing mixed, measured or run. Limitations: Documents and code read 2026-10-22; nothing mixed, measured or run. None of these numbers is a measured intelligibility outcome. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://www.dropbox.com/s/7peycr6cfhh22x1/TechnicalDeliveryStandardsBBCAudioMixGuidlines.pdf?dl=1",
      "note": "BBC Best Practice Guide - Sound Mixing v5.0.5 (2025), pp.4-7; Channel 4 DPP Programme Delivery Specification v5.2, loudness table p.15; EBU R 128 s4 (Geneva, November 2023), recommends (b), (i), (j); EBU Technical Review June 2022, Speech Intelligibility in TV"
    },
    {
      "url": "https://assets-corporate.channel4.com/_flysystem/s3/documents/2023-03/ProgrammeDeliverySpecificationFile_DPP-Channel4_v5.2.pdf",
      "note": "BBC Best Practice Guide - Sound Mixing v5.0.5 (2025), pp.4-7; Channel 4 DPP Programme Delivery Specification v5.2, loudness table p.15; EBU R 128 s4 (Geneva, November 2023), recommends (b), (i), (j); EBU Technical Review June 2022, Speech Intelligibility in TV"
    },
    {
      "url": "https://tech.ebu.ch/docs/techreview/trev_2022-Q2_Speech%20Intelligibility%20In%20TV.pdf",
      "note": "BBC Best Practice Guide - Sound Mixing v5.0.5 (2025), pp.4-7; Channel 4 DPP Programme Delivery Specification v5.2, loudness table p.15; EBU R 128 s4 (Geneva, November 2023), recommends (b), (i), (j); EBU Technical Review June 2022, Speech Intelligibility in TV"
    },
    {
      "url": "https://tech.ebu.ch/files/live/sites/tech/files/shared/r/r128s4.pdf",
      "note": "BBC Best Practice Guide - Sound Mixing v5.0.5 (2025), pp.4-7; Channel 4 DPP Programme Delivery Specification v5.2, loudness table p.15; EBU R 128 s4 (Geneva, November 2023), recommends (b), (i), (j); EBU Technical Review June 2022, Speech Intelligibility in TV"
    }
  ]
}