Extensive acoustical measurements were made in ten different atrium spaces varying in volume from 3 300 to 45 000 m[sup 3]. Impulse responses were measured at between 18 and 71 combinations of source and receiver position in each atrium depending on the size of the atrium. The computer-based measurement system (RAMSoft-3) used a maximum length sequence signal and a fast Hadamard transform procedure to obtain 5-s-long impulse responses. Octave band values of decay times, sound levels, and energy ratios were calculated for each impulse response. The average values of each quantity in each atrium were used to characterize typical acoustical characteristics of untreated atria. These allow rough estimates of the acoustical conditions in other atria as a function of the volume of the spaces.