Minimization of interior cabin noise has been a key topic of research in the automobile industry for the last two decades. This problem was initially approached via passive noise cancelation methods, where physical treatments such as structural damping and acoustic absorption were used. However, with vehicle manufacturers striving for more economical and lightweight designs, the resulting car interiors invariably became noisier due to the increased structural vibrations. These noise fields are generally dominanted by low frequencies (i.e., 0-500 Hz) [1], [2], hence, the conventional passive noise cancelation approaches are less effective. In an attempt to resolve the aforementioned problem, active noise control (ANC) methods were developed where secondary sources were proposed to attenuate the noise inside the cabin. With modern in-car entertainment systems providing four to six built-in loudspeakers, the addition of an ANC system comes at a relatively low additional cost.

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Recent Advances in Active Noise Control Inside Automobile Cabins: Toward quieter cars

Noise control and cancellation over a spatial region is a fundamental problem in acoustic signal processing. In this paper, we utilize wave-domain adaptive algorithms to iteratively calculate the secondary source driving signals and to cancel the primary noise field over the control region. We propose wave-domain active noise control algorithms based on two minimization problems: first, minimizing the wave-domain residual signal coefficients, and second, minimizing the acoustic potential energy over the region, and derive the update equations with respect to two variables, the loudspeaker weights and wave-domain secondary source coefficients. Simulation results demonstrate the effectiveness of the proposed algorithms, more specifically the convergence speed and the noise cancellation performance in terms of the noise reduction level and acoustic potential energy reduction level over the entire spatial region.

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Active Noise Control Over Space: A Wave Domain Approach

A survey on active noise control in the past decade–Part II: Nonlinear systems

https://dr.ntu.edu.sg/bitstream/10356/151258/2/1-s2.0-S0360132321003322-main%20%281%29.pdf

Ten questions concerning active noise control in the built environment

Selective fixed-filter active noise control based on convolutional neural network

In this paper, we investigate active noise control over large 2D spatial regions when the noise source is sparsely distributed. The l1 relaxation technique originated from compressive sensing is adopted and based on that we develop the algorithm for two cases: multipoint noise cancellation and wave domain noise cancellation. This results in two new variants (i) zero-attracting multi-point complex FxLMS and (ii) zero-attracting wave domain complex FxLMS. Both approaches use a feedback control system, where a microphone array is distributed over the boundary of the control region to measure the residual noise signals and a loudspeaker array is placed outside the microphone array to generate the anti-noise signals. Simulation results demonstrate the performance and advantages of the proposed methods in terms of convergence rate and spatial noise reduction levels.

/pdf/sparse-complex-fxlms-for-active-noise-cancellation-over-4p6l0z7fbo.pdf

Sparse complex FxLMS for active noise cancellation over spatial regions

Multi-channel active noise control (ANC) is currently an attractive solution for the attenuation of low-frequency noise fields, in three-dimensional space. This paper develops a controller for the case when the noise source components are sparsely distributed in space. The anti-noise signals are designed as in conventional ANC to minimize the residual errors but with an additional term containing an ll norm regularization applied to the signal magnitude. This results in that only secondary sources close to the noise sources are required to be active for cancellation of sparse noise fields. Adaptive algorithms with low computational complexity and faster convergence speeds are proposed.

/pdf/multichannel-active-noise-control-for-spatially-sparse-noise-35nwmhhmme.pdf

Shouda Jiang

Papers

Active Noise Control Over Space: A Wave Domain Approach

Sparse complex FxLMS for active noise cancellation over spatial regions

Multichannel active noise control for spatially sparse noise fields