In architectural acoustics, specific acoustic characteristics and treatments are carefully observed and evaluated for performance design. In the case of Jakarta, the acoustic observations conducted in one small theatre at the complex of TIM Art Centre. The capacity of the theatre is for 250 people, generally used for theatre and musical drama, and sometimes are used for musical, choir, and chamber orchestra performances. The plan shape is shoebox, designed with a proscenium stage and two tiers of shallow balconies. Recently, the electro-acoustic is used for the performances, although it is not necessary. This paper evaluates the acoustic properties of the theatre in relation with its architectural design and the surrounding materials used for the theatre. The acoustic measurements involved are for reverberation time by applying different techniques. A computer simulation measurement technique is employed by using CATT Program V7. Besides, real time measurement is also conducted. The derived acoustic parameters are then confirmed with the theoretical predictions, in order to check the accuracy of the results. The results obtained from the measurements indicated that the RT values derived from computer simulation were shorter when compared to on site measurements and the theoretical predictions. Design of the theatre is appropriate regarding its RT for multipurpose performances as well as the interior design for architectural point of view, and therefore the application of electroacoustic is actually not necessary.