This study explores audio theory and how product structure and material choice influence the generation of (unwanted) sound. The Philips Avent breast pump served as a case study to apply these insights, with the goal to reduce negative acoustic experiences during use. The existing design was first measured and analysed with dedicated instruments to characterise the sounds. Combined with user feedback, this analysis informed subtle targeted redesigns to address specific issues, such as removing sharp high-pitched tones or low humming noises.