One of two project reports. Part A can be found at: http://hdl.handle.net/11375/17932 / Time-averaged holographic interferometry is applied to the study of the resonance mode structures of an electromagnetic and a piezoelectric high frequency loud-speaker. Vibrational amplitude measurements were made using the simple concept of the holo-diagram. The vibrational amplitude sensitivity range was from 0.1 µm to 0.9 µm, which is an ideal range since the speaker vibrational amplitudes were always below 0.8 µm. Application of the technique to non-destructive speaker quality testing and optimum speaker design is also discussed in the report. / Thesis / Master of Engineering (ME)