Abstract:

An attempt is made to refine a standard active noise-control algorithm in order to take into account the unique response of the human auditory system. It has been shown that decreasing the sound-pressure level at a location does not guarantee a similar decrease in the perceived loudness at that location [W. R. Saunders and M. A. Vaudry, Proc. of Noise-Con 96, 385--390 (1996)]. Typically, noise cancellation is based on the ``error signal'' from a mechanical device such as a microphone, whose response is nominally flat in the frequency range of the human ear. However, if the response of the ear can be approximated by digitally filtering the error signal before it reaches the adaptive controller, one can, in effect, minimize the more subjective loudness level, as opposed to the sound-pressure level. The work reported here entails simulating noise control based upon minimizing perceived loudness for a varied collection of input noise signals. A comparison of the loudness of the resulting error signal is made to the loudness of the error signal resulting from standard sound-pressure-level minimization. This comparison helps assess the worthiness, for a given noise signal, of utilizing the extra processing time this technique requires.