In this paper, we apply two commonly used virtual sensing (VS) methods: the remote microphone method (RMM) and auxiliary filter method (AFM) to a headrest active noise control (ANC) system with the adjustable structure we have already proposed. The VS methods are used to overcome the case that error microphone cannot be placed at the target due to application limitations or physical constraints. The adjustable headrest structure allows secondary loudspeakers and the corresponding microphone to be moved as a single unit while maintaining the relative distances between the secondary loudspeakers and microphone constant, to ensure that the related plant responses are consistent. The noise attenuation performance of multichannel adaptive feedback control algorithms incorporating two VS methods at designated locations was evaluated in a room under nominal and non-nominal conditions. Experimental results demonstrate that the headrest ANC system with VS methods was superior to that without VS methods in terms of the nominal noise reduction performance. And the noise attenuation effectiveness of the RMM and AFM was at the same level in this case. However, the non-nominal performance of the VS methods against primary source variations may be inferior to that of the non-VS methods with indirect control by the physical monitoring microphone.

Active noise control; Headrest; Virtual sensing methods; Adaptive feedback control; Nominal performance; Non-nominal performance;