The paper deals with the tools for the acoustic design of auditoria, and the development of these tools during the last century. Ripple tanks could model the wave nature of sound in a reflecting enclosure, but only in two dimensions. Scale models using high frequency sound waves have been used for testing the design of new auditoria since the 1930es. The development of the room acoustic parameters flourished along with the development of scale model technique. But also the possibility to listen to the sound in the model was a challenge since the early days. The first computer models for room acoustic design appeared around 1967 and during the1990es they have matured. The results became more and more reliable, the calculation speed increased significantly, and new methods for acoustic analysis of the auditorium were developed, one of them being the possibility of producing high quality auralization.