Lombard reflex

Lom·bard re·flex

(lom'bahrd rē'fleks)
The increase in vocal intensity when talking in a background of noise. It is the speaker's unconscious effort to be heard over the noise.
References in periodicals archive ?
So-called Lombard Reflex - the automatic changes in speech which people make when they are speaking in a loud environment or against certain types of background noise - is one of the most difficult problems facing the worldwide field of speech recognition.
Named after the researcher who first noticed the effect in 1911, the Lombard Reflex makes it extremely difficult to have 100% accurate automatic speech recognition systems because we all change our voices depending on background noise.
Moreover, in locations where the background noise is loud the user tends to modify his or her voice according to what we term the Lombard Reflex.