In situ absorption measurement of antinoise devices using pre-determined pulse waveforms

Abstract

Noise barriers can be characterized by using the Adrienne method which combines MLS signals with the subtraction technique. This paper deals with a method to shape the loudspeaker-microphone impulse response which utilizes inverse filtering techniques to design the waveform radiated by the loudspeaker according to some prescribed criterion. For instance, zero-phase cosine-magnitude waveforms provide minimum length within a given frequency band. Therefore, this technique allows approaching the microphone to the loudspeaker, and as a consequence, reduces the lowest reliable frequency of the absorption measurement.