## 1 Introduction  
Active noise control (ANC) is widely used as it reduces noise at low frequencies. Global ANC can achieve a larger-space noise reduction in the control zone [1; 2; 3], while local ANC can realize multi-zone noise reduction [4; 5; 6]. However, under some special circumstances, such as anti-detection and noise reduction between seats where the sound field is distributed over multiple zones, it is necessary to decrease the increase of sound power outside the control zone when a large noise reduction is required in the control zone to prevent the detection and disturbance of others. In other words, control with directivity is needed. In addition, most of the existing control algorithms focus on how to maximize the noise reduction in the control zone only, and neglect the increase of sound power outside the control zone. Therefore, it is necessary to apply a new control algorithm to consider both of the two parts.  
While there is scarce research in ANC, enormous effective algorithms are proposed to form a directional output from a loudspeaker array for sound field reproduction [7; 8; 9]. [PERSON] et al. applied the acoustic contrast control (ACC) [10] algorithm to an active headrest [11]. For active headrest systems, the ACC algorithm eliminates the effect between the adjacent seats and increases the noise reduction in the control zone by 20 dB. [PERSON] et al. [12] used a constrained least-squares (CLS) algorithm to make the output of the loudspeaker array directional, thereby, achieving directed noise reduction. In addition, [PERSON] [13] proposed a control strategy that combines an optimized loudspeaker array and zero pressure constrained points, in order to control the scattered sound field of a rigid sphere. This new control algorithm has good reduction performance in the target areas and less amplification outside the target zone. However, this new control algorithm is not a wideband. In addition, the least-squares approach with acoustic contrast control constraint (SFR-ACC) [14] balancing the spatial average error and the acoustic contrast has been used in personal audio system. However, this algorithm has never been applied in ANC.  
To verify the feasibility of the SFR-ACC algorithm in ANC and to realize multi-zone directional ANC, three wideband ANC algorithms based on the ACC, CLS and SFR-ACC concepts are proposed in this paper. Using a loudspeaker array, the three algorithms form directional outputs and realize dual-zone ANC by reducing the noise in one zone, without changing the sound power in the other zone. The three methods described in this paper utilize white noise to model a wideband transfer function that reduces time and resource consumption and makes implementation easier. Compared with the traditional LS algorithm in dual-zone ANC, the three algorithms proposed in this paper, not only realize that the sound power in one zone is increased by less than 1 dB, but also reduce the noise in the other zone by more than 10 dB. The remainder of this paper is organized as follows. In Section 2, a brief overview of the dual-zone ANC, the mathematical formulation of the three algorithms, and the criteria of the algorithm performance are outlined. The experimental results are provided in Section 3. Finally, some conclusions are given in Section 4.