Understanding underwater acoustic communication: more than frequency

The intrinsic diversity between different types of underwater sound, namely natural sound, animal vocalizations and man-made noise, is heuristically evident. However, in order to reliably assess the prominence, or impact, of one type of sound into another, what is needed is a metric for evaluating objectively such differences in terms of their suitability to communicate some useful information: that is, to their functionality. Since their inception one century ago, studies in underwater sound have traditionally proceeded through analysis methods based on the frequency domain. However, the evaluation of information contents in underwater communication, that is of its functionality, may be effectively conducted by means of techniques, originated from and widely used for speech analysis, based on the combined evaluation of a set of quantities named prosodic parameters. These parameters refer to specific physical quantities and to their corresponding perceptive parameters, for which determining and preserving time modulations is essential. Such techniques may expand the conventional time-based or frequency-based approach into an unexplored multidisciplinary context blending various branches of acoustics, biology, and cognitive sciences together.