Musical timbre combfilter-coloration from reflections

Tor Halmrast
DAFx-1999 - Trondheim
Coloration is defined as changes in Timbre/ ”Klangfarbe”. Adding a reflection will automatically change the frequency response of a signal, giving some kind of coloration. This might be looked upon as distortion. However, reflections has been a natural part of sound distribution since the Greek amphi-theatres, indicating that some coloration must be acceptable, or even “wanted” , depending of the type of signal/musical material. The question is: “Which reflections give disturbing/unwanted coloration”? Part 1 gives a general overview of combfilter-effect for different time-delays. Part 2+3 gives the main results of a large practical investigation of coloration on orchestra platforms in concert halls. In Part 4+5, these results are compared with psycho-acoustical studies on coloration.