Interactive sonification of German wheel sports movements

This paper presents the design, implementation and evaluation of a sonification system, which gives real-time auditory feedback to a performer who is carrying out moves on sports equipment called a German wheel. The paper starts with a brief description of different German wheel move categories and of relevant research on movement sonification to present how these motivated some of our design decision. Thereafter the structure and functionality of the sonification system, which is implemented in the programming language SuperCollider is discussed, including its division into three sub-tasks. These sub-tasks are data acquisition, feature extraction and sonification. The data acquisition uses a magnetometer to collect data about the motion of the wheel. By measuring the magnetic field of the earth, it acts similar to a compass and allows to determine the orientation of the wheel. This orientation is one of the main features that are derived from the input data in the feature extraction process. A set of further features is derived from the input data and the orientation of the wheel. The choice of these features was inspired by the background knowledge about the different wheel move categories and accordingly the task a performer who is using the wheel is confronted with. Finally the system uses the features to produce an acoustic representation of the motion. We implemented four different sonifications: the Direct-data sonification, Cartoonification, Vowel synthesis sonification and Event-based sonification. The Direct-data sonification uses the unprocessed input data to generate an acoustic feedback, which leaves the interpretation completely to the user. The Cartoonification uses some of the features to imitate and amplify a natural rolling sound. The Vowel synthesis represents the motion of the wheel through synthetic vowel sounds. The idea is based on the thought that