History and current state of the war between the two main approaches to surround sound: discrete speaker feeds versus hierarchical matrix

40th AES Conference - Tokyo, 8-10 October 2010

The ORF seminar

System C: OCT (Optimised Cardioid Triangle) + Hamasaki-Square; This system was devised by Guenther Theile. OCT chooses hypercardioids facing 90° away from the orchestra for L and R (base distance b=80cm) and a cardioid facing forward for C closer to the orchestra (h=8cm). The somewhat poorer bass response due to construction principles is compensated with the addition of two omnis adjacent to the hypercardioids which are lowpass-filtered at 100Hz to provide low-end down to 20Hz (The hypercardioids and the cardioid are highpass-filtered at 100Hz accordingly.)