Lombard effect describes raising vocal intensity when background noise is loud

Evidence

The amplitude shift or Lombard effect is the tendency for a speaker to increase the intensity of its vocal level to improve the intelligibility of a speech signal when in the presence of a loud background noise. This effect has been named after the French ear specialist, Etienne Lombard, who discovered this phenomenon in human speech (Lombard 1911). — Almo Farina, Soundscape Ecology, 1296

Categorization

• DEFINE: Defines Lombard effect and its named source, core vocabulary for the noise-adaptation chapter.
• XREF: connects to: Species shift calls to ultrasonic frequencies to escape constant noise masking — Almo Farina, Soundscape Ecology: Principles,…, 1288; Insects cannot exhibit the Lombard effect because stridulation is unmodulable — Almo Farina, Soundscape Ecology: Principles,…, 1299