EEET5121 Engineering Minor Thesis

Summary

This paper seeks to simulate the small room impulse response acoustic behavior design using MATLAB software. Room acoustics is a field that concentrates on all the aspects surrounding the production, transmission and reception, control and impact of sound in a given environment. The sound produced by a music system or human being is transmitted and either gets reflected or absorbed by the materials in its surrounding. The surrounding matter with soft surfaces, for instance, textiles and batt insulation, may absorb the sound waves and as such the sound signals do not move beyond that. When the matter is comprised of firm surfaces such as earthenware tiles, gypsum panel or lumber, the sound signals are reflected. Acoustic engineers while designing may purpose to include a form of reproduction reverb so as to make adjustments to the recording made in the dry surrounding and, as a result, improve the acoustic wave ambience. All interior designers and acoustic designers seek to eventually simulate a natural reverb. In acoustic design, the vibrations can still be considered undesirable. The vibrations are perceived to waste energy and create unwanted sound also known as noise. The vibrational motions of engines, electrical and induction motors may result in imbalance at the rotational parts causing uneven friction and unwanted meshing of the gear. Most of the analysis is preferably done in frequency domain but signals travel in time domain. The model used features a rectangular enclosure with an impulse response for the source to the receive.

Recommendations

(i) For critical distance measurements, especially in sound recording studios or media broadcasting studios one can use the log frequency response variation as it guarantees accuracy and measures accurate distances to a very definitive precision with a focus on the reverberation radius.

(ii) The use of the log frequency response variation technique may be the most accurate simulation model to use for the implementation in rectangular nonrigid wall enclosures. The model provides results very close to the theoretical estimations.

(iii) The international body, ITU-R, recommends that the tests on the system models developed for various acoustic rooms be done using an experiment and managing the results using statistical methods.

In a nutshell, the impulse response of a small room is dependent on the reverberation time and the time a sound signal takes to decay. These two independent variables determine how much a sound wave stays on air before decaying away completely as well as the time between the arrival time and the last signal arrival time. Small rooms are used in sound recording studios, media reporting studios, meditation rooms etc. The interior designs for these rooms are customized to ensure the sound disruptions are almost negligible. Some of the sound disruptions discussed in the report are echo, fluttering, temporal coloration, timbral difference, wavering, whooshing, spectral coloration, and rattle. The desired room acoustical characteristics vary depending on the room’s designated purpose.