The sound of musical instruments is typically very distinct with each instrument having its own character that mixes with the character of the listening room. While the audiophile connoisseur describes this with the vocabulary of a wine taster, it is also possible to measure these effects separately to obtain objective descriptions thereof.

The first step is to separate the influence of the instrument from the influence of the listening room. This is done by recording the music in an anechoic environment to enforce free field conditions. Usually only a few or even just one microphone per instrument are used, so that the spatial variance of the sound is lost in the recording. In presence of a listening room however, all directions of sound radiation contribute to the perceived tonal characteristics of the instrument, an effect which is often ignored in sound recordings.

In order to perform a multi-channel sound recording, a large surrounding microphone array was constructed at ITA placing 32 microphones spherically around the musician. With a diameter of more than four meters it is large enough to encompass most instruments in order to measure the sound radiation simultaneously in 32 directions.

The goal of this thesis is to evaluate the existing measurement setup in terms of accuracy of the obtained results and to improve the setup for better performance. Experiments with a single loudspeaker as known sound source give insight to the effects encountered in the multi-channel recording, such as individual sensitivity and directivity of the microphones and influence of the microphone housings. Different centering algorithms can be applied to detect the location of the actual radiating source. The recordings from a large set of musical instruments and simulation results of the existing array structure can be used for this work.

In the end a modified version of the spherical microphone array shall be designed and evaluated after the applied modifications. Due to the presence of mechanical and electrical workshops in the institute, the practical realizations of the proposed modifications are supported to speed up the design process.