Influence of the speaking style and the noise spectral tilt on the lombard reflex and automatic speech recognition

To study the Lombard reflex, more realistic databases representing real world conditions need to be recorded and analyzed. In this paper we 1) propose a procedure to record Lombard data which provides a good approximation of realistic conditions and 2) present a comparison between two sets of experiments where subjects are in communication with a device while listening to noise through open-ear headphones and where subjects are reading a list. By studying acoustic correlates of the Lombard reflex and performing off-line speakerindependent recognition experiments it is shown that the communication factor affects the Lombard reflex. We also show evidence that several types of noise differing mainly by their spectral tilt induce different acoustic changes. This result reinforces the notion that it is difficult to separate the speaker from the environment stressor (in this case the noise) when studying the Lombard reflex.