Microphone Thermal Agitation Noise

A Thermal Transducing Microphone

(6) If we now assign T0 to be the undisturbed air temperature of the surroundings, p as the small perturbation in pressure due to an acoustic wave and P0 as the ambient pressure we can derive the change in temperature occurring with a passing acoustic wave. ∆T is very small and is approximately ±0.23C with a very high sound level of 140 dB(SPL), ambient temperature of 20C, and an ambient pressu...

Noise cancelling for microphone arrays

In this paper an application of the noise cancelling method for suppression of noise of a microphone array system is discussed. First an overview of the noise cancelling approach is given. This is followed by a description of the employment of the method in a realized microphone array system. The limiting factors are described and theoretical limits of the noise suppression are derived. Experim...

Dual Microphone Noise Reduction Algorithms

General Considerations of Noise in Microphone Preamplifiers

In this paper a study of the noise performance of electret microphone systems as a part of hearing aids is presented. The signalto-noise ratio of the microphone-preamplifier combination, containing a field-effect transistor (FET) and a high value resistive bias element in a hybrid configuration, is mainly determined by the noise generated in the preamplifier circuit. A theoretical analysis of t...

Noise Reduction using Paired-microph Microphone Arran

A wide variety of microphone arrays have been developed, and the authors have also proposed a type of equally-spaced small-scale microphone array. In this approach, a paired-microphone is selected at each frequency to design a subtractive beamformer that can estimate a noise spectrum. This paper introduces a nonequally-spaced microphone arrangement, which might give more spatial information tha...