Room Acoustics and Speech Reception: A Model and Some Implications

Summary

An explanatory model separates direct speech, early reflections, late reverberation and background noise when predicting speech reception.

Key findings

• The direct speech component falls by 6 dB per doubling of distance. Reflected sound also contributes, so this is not a rule for the total level at every indoor seat.
• The model combines direct speech and early reflections as useful signal and treats late reverberation as an additional masking contribution. A measured speech-to-background-noise ratio can omit this reverberation penalty.
• Its illustrative audibility model reaches full signal audibility at +15 dB effective SNR. Translating audibility into word recognition depends on hearing, language, context and listener skill.
• Raising loudspeaker output raises both useful speech and its late reflections; the model predicts less benefit when late reverberation dominates than when independent background noise dominates.

Limits

Model and worked examples, not a new listener trial or a universal hearing-loss threshold. The extracted chapter has no explicit publication date, so none is inferred from search results or file metadata. Classroom amplification and personal FM examples are used only to explain the acoustic path; neither is a venue product recommendation.

Read the original

www.phonak.com/content/dam/phonak/en/evidence-library/journal-article/ACCESS_Chapter_22_Arthur_Boothroyd.pdf

Link checked 13 October 2026. We link to the original and do not host copies.

Cited in

• How much do room acoustics and distance limit listening without a system, and what follows for choosing one?Partly answered

Cite this source

The original gives no date, so the citation says “n.d.”. The accessed date is when this library last checked the link; use the date you read it. To point readers to this summary instead, link to https://assistivelisteningknowledgebase.org/evidence/boothroyd-room-acoustics/

Every finding here cites its source, and who funded each source is labelled. This site does not recommend products. Found an error or a missing study? Suggest a correction.