Two-channel acoustic noise control system

Abstract

The results of the development and experimental verification of a two-channel acoustic noise control data processing system that provides real-time control of non-deterministic broadband acoustic noise are presented. The system is implemented using the LabView graphical programming language G. The length of the measured realization is determined by the sample size ratio to the sampling frequency, and the number of measurements of each sound signal is determined by the ratio of the analysis time to the length of the measured realization. The measured realization of the audio signal in the form of 40,000 16-bit binary numbers is processed using the fast Fourier transform. As a result of processing, a discrete audio signal spectrum is obtained in the range from 0 to 20 KHz in steps of 1 Hz. To check the quality of the system’s functioning, a pair of microphone capsules of the MDN-318, wm61, etc. types, widely used in computer audio equipment, preliminarily selected according to the amplitude-frequency characteristics. The results of system verification using a laboratory acoustic chamber are presented. The advantage of the system is the receipt of a difference spectrum of controlled signals. The conclusion is drawn about the possibility of using this system for a qualitative assessment of changes in the noise level along the propagation path, as well as additions to the results of measurements performed by standard methods.