Constant Hak is researcher and professor at the TU/e in the unit Building Physics and Services of the Department of the Built Environment. He is a leading expert in the development of new measurement techniques and methods for investigating the acoustics of spaces. His software tools and equipment are being used worldwide by researchers and engineers. Besides, Constant Hak is often nominated by the students as one of best teachers at TU/e. Highlights are the measurement expeditions organized together with students, among others investigating the Ice Hotel in Sweden and the underground cities in Cappadocia, Turkey.