Experimental evidences of nonlinear programmable electroacoustic loudspeaker

A two degrees-of-freedom system coupling an acoustical mode of a closed tube to an electroacoustic loudspeaker is considered. A model-inversion technique is presented to digitally program the impedance of the loudspeaker for reaching a targeted nonlinear behavior. Experimental results show that the programed nonlinearity can guide the system to both periodic and non-periodic responses while acoustical levels for activation of the nonlinearity are less than the ones for systems with passive nonlinear oscillators (94 and 100 dB in this paper compared to 138 dB in previous papers), allowing building applications. Moreover, it is spotted that the programed nonlinearity of the electroacoustic loudspeaker, even in its non-optimized form, performs nonlinear noise control for some frequency ranges. The main objective of this article is to show that it is possible to program the behavior of an electroacoustic loudspeaker.