Over the past twenty years, a scientific community has emerged which dedicates itself to the development of auditory data displays or sonifications. Much like visualisation refers to the transformation of scientific data into images, sonification translates data into sound. While sophisticated technology is not a technical precondition for sonification – a dataset can be expressed by humming or by playing a tune on the piano – sonification usually relies on the possibilities afforded by digital audio technologies; indeed, the history of the field is intimately intertwined with technological developments such as tools for sound synthesis and processing. However, the epistemic status of sonification is contested, and many scientists react with scepticism to the idea of turning their data into sound, arguing that knowledge gained through listening cannot be objective. This paper analyses the strategies used by the sonification community in its struggles for scientific legitimacy. In their quest for acceptance, the practitioners of sonification link up to older traditions of listening as an entrance to knowledge, such as the listening practices of physicians and car mechanics. At the same time, they criticise the ‘visual bias’ of Western science and bemoan the lack of a ‘lobby for the ear’; they thus engage in an emancipatory rhetoric that promises to free the ear from its marginalised status. In doing so, they walk a tightrope between linking up to and breaking away from established scientific practice, accomplished in part through a careful navigation of the boundaries between art and science. In their ongoing struggle for scientific legitimacy, the community also cultivates a sense of professional audition (cf. Goodwin 1994, Porcello 2004); that is, a set of technological and perceptual skills that characterise a competent practitioner of sonification. The professional audition of sonification is a matter of listening (and indeed, of engaging in different strategies and modes of listening), but it is also a matter of tinkering with audio hard- and software and of communicating about sound – for instance, by using specialised audio vocabulary, but also by humming, singing and gesticulating. Ironically, considering that the rhetoric employed by the sonification community often talks of endorsing the ear, it is not just the ear but the whole body of the researcher which is involved in the professional audition of sonification.