A Novel Approach for Impulse Response Measurements in Environments with Time-Varying Noise

A typical measure taken against unavoidable noise during the measurement of an impulse response of an acoustical system is to repeat the measurement a couple of times and coherently average the distinct measurements. With stationary noise this is the optimal solution which gives an improvement of the signal-to-noise ratio of about 3 dB per doubling of the number of measurements averaged. If transient or time varying noise components are present the resulting accuracy suffers significantly. In this contribution, the authors propose a weighted averaging approach where the distinct measurements are weighted according to the present noise power. The noise power is estimated with the so-called SWiC method (sliding window correlation) recently published by the authors.