1:50 scale acoustic models for objective testing of auditoria

Abstract The particular problems of small-scale models, namely air absorption and transducers, are discussed and it is found that with a dehumidified atmosphere (2–3 per cent relative humidity) and currently available transducers the measurement of reverberation time, as well as impulsive type measurements such as early to late energy ratio and early decay time, is possible at a scale of 1:50. The upper frequency limit for reverberation time is the 2 kHz octave equivalent and the 1 kHz octave for impulse measurements. Comparable measurements made in an auditorium and its 1:50 scale model showed good agreement. Some results of measurements in a model theatre and concert hall are also reported. It is concluded that 1:50 scale acoustic models enable one to measure quantities which cannot be calculated from drawings and offer a valuable aid for the development and confirmation of an auditorium design.