Kugelmikrofonarray zur Abstrahlungsvermessung von Musikinstrumenten

Diploma thesis (pdf 5.000 KB)

Usually a single microphone is regarded sufficient to record the sound of a musical instrument. However, its location has a crucial influence on the timbre due to the radiation characteristics of the instrument. Conversely, this thesis considers an arrangement of microphones capturing the radiated sound in a complete set of surrounding directions, simultaneously. Therefore a measurement environment is planned and constructed to position the microphones around the musical instrument. For the microphone placement, a spherical arrangement of sampling points is considered, in the centre of which a musician shall actually be able to play an instrument. To find the most suitable microphone layout for the measurement purpose, a sampling strategy is evaluated to capture the radiation of the instrument evenly. An interpolation method allows to calculate continuous radiation patterns, which can be displayed more easily, graphically. The hereby enabled sound-radiation analyses are performed on different musical instruments. Woodwinds, brass instruments and strings are compared to show differences between groups of instruments. Eventually, the analysis provides the basis for a survey on the radiation patterns of partial tones at the same frequency, but associated to different fundamental tones. Simplified to a scalar number, the correlation coefficient of these radiation patterns are investigated to observe their similarity.