Automotive audio is challenging for a variety of reasons. The acoustic environment is noisy, the geometry is complex with many reflecting surfaces,; there are several listening positions of interest. While digital signal processing can to some degree alleviate some of the associated issues, there often is a need for specialized waveguides that directly affect the sound propagation from the transducers. However, with the desired objectives being quite intricate; involving on-axis pressure, directivity, beam width,; possibly other metrics, the design process is highly non-trivial. A strategy based on acoustical topology optimization is presented here,; where a tweeter waveguide to be mounted in the dashboard is optimized towards certain objective functions.