Products are no longer solely judged on their functionality; this is nowadays taken for granted. Today's products distinguish themselves by the user experiences they elicit. Depending on the product at hand, audition may play an important role in establishing such an experience. Therefore, it is important for product designers to consider the quality of the auditory experience. A typical design process consists of four phases: problem analysis, conceptual design, embodiment design, and detailing. A final prototype is commonly built during the last design phase, often it is only at that time the sound of a product becomes apparent. The sound may be evaluated, and should it fail to comply with the aimed user experience, a large part of the product may have to be redesigned. The product development process could be much more efficient if product sound design is incorporated from the very beginning. Product sounds, as emitted by domestic appliances (e.g., electric tooth brushes, microwave ovens, alarm clocks, etc.), are composed of sound producing mechanical and electrical parts. Various sounding models and tools have already been developed to imitate the sound of product parts. However, at the beginning of a product design process often no knowledge is yet available on the parts to be used. Contrary to sounding models, no tool to sketch product sounds existed, until now. This graduation project concerns the conceptual development of PSST: a Product Sound Sketching Tool. PSST is a sketching tool consisting of a collection of playful physical icons (phicons), a table, and a web-cam connected to a product sound synthesizer. The synthesizer can be controlled by manipulating phicons on the table. Each phicon resembles the sound parameters it manipulates by means of its visual and tactile design. PSST allows unexperienced industrial sound designers to create ideas for product sounds belonging to different product sound categories. Findings of two experiments demonstrate this activity can be characterized as sketching. Furthermore, the findings strongly suggest that the tool facilitates an interpretive cycle, and consequentially thinking sketching. Finally, findings demonstrate that the tool allows for intentionally creating energetic product sound sketches. PSST is specifically designed for the conceptual design phase. Proposals have been made to integrate PSST in a design studio environment. These proposals include exchanging sound sketches between design team members, modifying existing sound sketches, and coming to a fine-tuned compromise during design meetings. PSST is a first step in designing product sounds from the very beginning of the design process. When the resulting product sound sketches are used as guide throughout this process, a final prototype can be developed more efficient and more effective. The sound of this prototype will then comply with the intended product character, and the experience the product is supposed to evoke. PSST was realized through iterations of building, testing, interviewing, and creative sessions with (sound) designers. The project took place at ID-StudioLab, a design research community at the Faculty of Industrial Design Engineering, Delft University of Technology.