Publications Repository - Gdańsk University of Technology

Focusing sound in rooms intended for listening to music or speech is an acoustic defect. Design recommendations provide remedial steps to effectively prevent this. However, there is a category of objects of high historical or architectural value in which the sound focus correction is limited or even abandoned. This also applies to indoor or outdoor concert shells, installations for teaching and acoustic presentations, etc. The main content of this article is deriving the equation of a caustic created by a concave hemispherical reflector with a source of rays situated at a given position. It is explained why under real conditions, both indoors and outdoors, no clear caustic resulting from the geometric approach is observed. Instead, its blurred form is perceived, usually limited to the caustic cusp taking the form of a point-like sound focus. This can be attributed to the effect of diffraction and interference, the impact of which on a caustic is analyzed in the paper.

Authors

• prof. dr hab. inż. Andrzej Kulowski link open in new tab