Spatial active noise control (ANC) systems aim to control the noise field over a spatial region. However, when both the desired field and the interference field co-exist, typical ANC systems lack the ability to selectively reduce the interference field, resulting in distortions in the desired field. In this paper, we design a spherical-harmonic domain selective spatial ANC system to reduce the interference field and preserve the desired field. The designed system integrates a desired field extraction (DFE) process, a sound field reproduction (SER) process, and an ANC process. The DFE and SFR processes are implemented to first capture and then reproduce the desired field, while the ANC process reduces the pseudo residual field. The simulation study shows that compared to two existing ANC solutions, the proposed design achieves a better overall performance with an acceptable speech-distortion-ratio within the sweet area in a reverberant environment

Spatial Active noise control (ANC) systems are proposed to minimize the noise over a spatial region of interest around people’s heads by generating an anti-noise field with multiple microphones and loudspeakers. Recently, a realistic microphone geometry was designed to allow the system to monitor the residual noise field without restricting people’s head movement. However, this design, which utilizes the remote microphone technique using an observation filter (OF) for noise field modelling, has a drawback that the system is not robust against variations in the noise source location. In this paper, we address this drawback and present an improved spatial ANC system that overcomes this limitation. The proposed system enhances its adaptability by selectively employing the most suitable OF from a set of pre-modelled discriminator filter (DF), tailored to the acoustic environment of the system. We demonstrate that the proposed method maintains noise reduction performance over the region of interest with a dynamic noise source with changing position and signal through simulation and physical measurements.

The creation of a spatial sound scene through binaural rendering draws increasing research interest, given the rising application of virtual reality and augmented reality. High-fidelity augmented reality audio requires accurate room acoustic simulation. Typically, this is achieved with binaural rendering of spatial sounds using recording of a Higher-Order Microphone (HOM) and Head-Related Transfer Functions (HRTFs) based simulations. However, HOM often fails to deliver full immersion due to the limited order of recording. In this paper, we introduce a Binaural Room Impulse Response (BRIR) calculation method based on HOM recordings of Room Impulse Responses (RIRs) to improve binaural sound rendering. The proposed method enables a more accurate analysis and rendering of the directive components in the limited-order spherical harmonic (SH) recording of RIRs with sparse recovery beamforming. Results with measured RIRs using a HOM indicate that the proposed method achieves a more accurate BRIR calculation than the conventional SH domain method.

Blind source separation aims to recover a series of unmixed signals from only a mixture recording of source signals. For the mixture of speech signals where sources have unique spatial positions, the relative transfer function has been found useful as it contains the spatial information of each source regardless of its signal. In this paper, we transfer a previous relative transfer function based separation method into the wave domain by utilizing a higher-order microphone for the mixture recording. Consequently, the higher-order microphone enables the processing with relative harmonic coefficients, which provides better independency between different coefficient components than the conventional relative transfer functions in each time frame. We demonstrate that the proposed method using relative harmonic coefficients outperforms the relative transfer function based method in highly reverberant rooms through simulation with both simulated and real measured room impulse response data.

Spatial active noise control (ANC) aims to reduce unwanted acoustic noise over a continuous spatial region by generating an anti-noise field with secondary loudspeakers. Conventionally, spatial ANC is achieved by using complex error microphone arrays such as grid or spherical geometry, which are impractical and obstruct the users to enter the quiet region. Recently, a spatial ANC system using circular arrays of microphones has been proposed such that the lower hemisphere of the region of interest is free of microphones for user’s head movement. In this structure, however, the error microphone located at the center of the region (the origin) blocks the head from moving up. In this paper, we optimize the aforementioned system in terms of the error microphone geometry. We remove the requirement to have a microphone at the origin by introducing a single-channel remote microphone technique to the spatial ANC system. Through real-world experiments, we demonstrate that the proposed method achieves noise reduction over space with a more user-friendly error microphone array design.

Spatial active noise control (ANC) aims to reduce unwanted acoustic noise over a continuous spatial region by generating an anti-noise field with secondary loudspeakers. Conventionally, spatial ANC is achieved by using complex error microphone arrays such as grid or spherical geometry, which are impractical and obstruct the users to enter the quiet region. Recently, the remote microphone technique has been introduced to spatial ANC systems without using error microphones inside the region of interest. However, this technique still requires an error microphone array during the tuning stage. In this paper, we further improve the remote microphone technique by introducing a spatial sound field recording method with a moving higher order microphone for the noise field recording (tuning stage) as well as secondary channel estimations (control stage). This eliminates the requirement for impractical microphone array geometries, typically required in existing spatial ANC solutions. The experimental data based simulation demonstrates the effectiveness of the proposed method on noise reduction over space with its feasible array design.

Active noise control (ANC) over space is a well-researched topic where multi-microphone, multi-loudspeaker systems are designed to minimize the noise over a spatial region of interest. In this paper, we perform an initial study on the more complex problem of simultaneous noise control over multiple target regions using a single ANC system. In particular, we investigate the maximum active noise control performance over the multiple target regions, given a particular setup of secondary loudspeakers. The performance analysis is carried out using a wave-domain representation to best represent sound propagation over multiple regions in a given enclosure. Furthermore, given the global primary noise field and a fixed secondary source setup, a subspace method is exploited to evaluate the best system performance that could minimize the residual noise fields over multiple regions of interest. We provide experimental results to demonstrate the effectiveness of the proposed method.

Spatial active noise control (ANC) systems focus on minimizing unwanted acoustic noise over a continuous spatial region. Conventionally, spatial ANC systems are proposed using point based multi-channel systems and recently novel methods have been developed using spherical harmonic analysis of spatial sound fields. A major limitation for implementing the latter approach is the requirement of regularly distributed microphones and loudspeakers over spherical surfaces. In this paper, we relax the above constraint by constructing a system utilizing multiple circular microphone and loudspeaker arrays and designing a corresponding ANC algorithm. By simulation, we show that the proposed method can achieve comparable ANC performance to conventional spherical array methods. By experiment, we demonstrate the feasibility of implementing the multiple circular array structure and verify its effectiveness given practical constraints.

Active Noise Cancellation (ANC) is a well researched topic for minimizing unwanted acoustic noise, and spatial ANC is a recently introduced concept that focuses on continuous spatial regions. Adaptive filter designing for spatial ANC is often based on frequency-domain spherical harmonic decomposition method, which has a major limitation due to the increased system latency. In this paper, we develop a time-domain spherical harmonic based signal decomposition method and use it to develop two time-space domain feed-forward adaptive filters for spatial ANC. Through simulations we show that the proposed methods can achieve higher noise reduction performance over the control region with microphones located on the surface of the region compared to the conventional time-domain adaptive filter.