Review of active noise control techniques with emphasis on sound quality enhancement

Abstract

The traditional active noise control design aims to attenuate the energy of residual noise, which is indiscriminative in the frequency domain. However, it is necessary to retain residual noise with a specified spectrum to satisfy the requirements of human perception in some applications. In this paper, the evolution of active noise control and sound quality are briefly discussed. This paper emphasizes on the advancement of active noise control method in the past decades in terms of enhancing the sound quality.

Fuzzy logic feedforward active noise control with distance ratio and acoustic feedback using Takagi–Sugeon–Kang inference

“…Secondly, the distance ratio is important. As can be seen from equation (6), any change in the location of the detector or the observer with respect to the noise sources will be reflected in the transfer function for the controller. The critical geometrical condition for optimal cancellation performance can be expressed as…”

“…Using equations (6) and (8), it can be shown that that the controller will have an infinite gain, under the condition in equation (8), for the noise level at the observer point to be reduced to zero. However, this cannot be realised in real life or in the simulation experiments.…”

“…The main principle of noise adsorption is to transform the acoustical energy into other form(s). 6 However, for most industrial acoustic waves, the main power is concentrated in the low-frequency range. Based on the relationship between the acoustic wavelength and frequency, the acoustic wavelength becomes larger at the low-frequency range and the corresponding result is that the size of corresponding absorption material required is increasing.…”

“…The essential principle of ANC technology is superposition, while a secondary sound wave is generated to interfere with the primary sound wave and achieve noise cancellation at specified (observation) point(s). Compared with PNC method, it not only successfully demonstrates its capability for removing the undesired sound at lower frequencies but also is convenient and flexible 6 setting up. In the early 1930s, Lueg 8 used microphone and an electronically driven loudspeaker to successfully cancel the noise and proposed the concept of active noise control and later registered this as the patent in the USA.…”

Physical configuration-based feedforward active noise control using adaptive second-order truncated Volterra filter

“…The passive control approach uses absorbers or barriers to attenuate the noise level, which transforms the acoustic energy to heat energy, and it has already demonstrated superior performance in high-frequency noise reduction. [4][5][6] However, for low-frequency noise, the passive approach is expensive and inconvenient, as increasing acoustic noise wavelength requires a larger size absorbing or damping material. To attenuate low-frequency noise, the active noise control (ANC) method, which is essentially based on the principle of superposition, is proposed.…”