Sound-Coloration from Close Reflections

Tor Halmrast
The effect of close reflections on coloration is often not taken into consideration when designing rooms. This paper will give an overview of coloration, comb-filters and "Box-klangfarbe". [1] Corridors are interesting with respect to acoustics. The length of a typical corridor is often within the "time domain", giving an echo. However, if we look at the cross section of a corridor, the dimensions are much smaller, leading to more interesting acoustical effects, as an extreme case of "close
more » ... ections". This paper presents observations and measurements of the acoustics of a corridor, investigations of comb-filter effects and examples of how even modest "diffusion" treatments of the sidewalls changes the perceived acoustics.