The acoustic quality of a concert hall has frequently poseda mysterious puzzle, namely, what physical aspects of thesound field can produce superior sound for the listener. Theauthor has been probing for more than adecade into thesubjective qualities preferred for musical and speechsounds. The result of his extensive investigations - thediscovery that four and only four independent parameterscontribute effectively to good acoustics - is summarized inthe present book. The capability of calculating acousticalquality at any seat in a proposed concert hall is a uniqueand quite useful aspect of Ando's design method. Alternativearchitectural schemes can be compared based on the number ofseats which exceeds a previously accepted minimum standardof acoustical quality.