This chapter introduces a new active noise control system for optimal control of the sound field around a human's head. Geometrical arrangements of error microphones are proposed around the head in a diffused noise field. In order to evaluate the controlled sound field, a rigid sphere theoretical model is used as a human's head in the computer simulations. In previous studies it was shown that the theoretical sphere model maintains a good approximation of a head-related transfer function (HRTF) below about 5 kHz. In this chapter the relationship between the noise reduction and the corresponding configuration of the error microphone and secondary source arrangement is evaluated. As a result, we found that the closely located secondary sources to the sphere head give significant noise reduction in a large control area. A possible arrangement of the error microphones is found to provide an optimal result according to a given control strategy, such as flatness of reduced sound pressure of the quiet zone.

Inspec keywords: active noise control; optimal control

Other keywords: computer simulation; head-related transfer function; error microphones; secondary source arrangement; adaptive prediction method; rigid sphere theoretical model; controlled sound field; sphere head; active noise control system; optimal control; human head; diffused noise field; sphere model; noise reduction

Subjects: Other nonelectric variables control