Speech production modifications produced in the presence of low-pass and high-pass filtered noise

In the presence of noise, do speakers actively shift their spectral energy distribution to regions least affected by the noise? The current study measured speech level, fundamental frequency, first formant frequency, and spectral center of gravity for read speech produced in the presence of low- and high-pass filtered noise. In both filtering conditions, these acoustic parameters increased relative to speech produced in quiet, a response which creates a release from masking for listeners in the low-pass condition but which actually increases masking in the high-pass noise condition. These results suggest that, at least for read speech, speakers do not adopt production strategies ill noise which optimize listeners' information reception but that instead the observed shifts could be a passive response which creates a fortuitous masking release in the low-pass noise. Independent variation in parameters such as F0, F1 and spectral center of gravity may be severely constrained by the increase in vocal effort which accompanies Lombard speech. (C) 2009 Acoustical Society of America. [DOI: 10.1121/1.3179668]