Naw, Chris; for example, Dr. Toole, in Sound Reproduction at p. 203("Optimizing Room Shape and Dimensions")states: "A recurring fantasy about rooms is that if one avoids parallel surfaces, room modes cannot exist. Sadly, it is incorrect". In the following pages are computed pressure distributions in non-rectangular rooms, showing irregular patterns of high and low areas. He further comments(p.204)that "The real difference is that in rectangular rooms, the patterns can be predicted using simple calculations".
