An investigation of acoustic impulse response measurement and modeling for small rooms
Room impulse response modeling has been a subject of interest to acousticians, musicians, and architects for many years. Room impulse response modeling can help to predict the acoustical characteristics of the new finished concert halls, to create a virtual studio effect for music production without building the actual studio room, and to compare the effect of different absorbing materials and treatments in architecture. The goals of this dissertation are to obtain a better match between the simulation and the measurement results of small room impulse responses, and to understand why the models and the measurements may differ even for simple cases like small rectangular rooms. The basic image source method and digital waveguide mesh are widely used in modeling small room impulse responses because they are relatively easy to implement.But the modeling results from these two computer models are often found to be of limited usefulness because the source, receiver, and room surfaces in the models are usually too idealized to match real conditions. For example, the computer models have often assumed the sound source to be an omni-directional point source for ease of implementation, but a real loudspeaker may include multiple drivers and exhibit an irregular polar response. We develop a room impulse response computer modeling technique that extends the basic image source method or digital waveguide mesh by including the measured parameters of the speaker, microphone, and room surfaces. We verify that the match between the model and the measurement can be improved if we include the real measurement of the speaker polar response, microphone polar response, and room surface reflection coefficients in the model.