9 accepted papers
This paper proposes a linear microphone array parallel to the driving direction for in-car speech enhancement. In contrast to other linear microphone arrays in the car cabin reported in a literature or implemented as a commercial product, the array axis is arranged in parallel to the driving directi…
In public spaces, it is important to reduce ambient noise and surrounding conversation sounds for smooth conversations. Since partitions are often installed at bank counters and shared offices to separate the space from the surrounding area, active noise control can be applied to these partitions. I…
In this paper, we propose a method for controlling the directivity of parametric array loudspeakers (PAL) by optimizing the weights for the sideband signals. By setting the weights for the sideband signals in the single side-band (SSB) modulation to the optimum values, the directivity of the audible…
The virtual sensing technique allows the active noise control (ANC) system to work with error microphones that are placed far from the desired zone of quietness (ZoQ). Conventionally, a training stage is required to obtain the auxiliary filters with the temporary error microphones placed in the ZoQ.…
Parametric array loudspeaker (PAL) modulates the audio input on an ultrasonic carrier and relies on airborne nonlinear acoustic effects to generate the audible sound output. The sound output is mainly confined in the beam of the ultrasonic carrier and thus shows a pronounced directivity. There are t…
When estimating the correlation/spectral structure of a locally stationary process, one should choose the so-called estimation bandwidth, related to the effective width of the local analysis window. The choice should comply with the degree of signal nonstationarity. Too small bandwidth may result in…
The ultrasound-to-ultrasound Volterra filter (U2VF), which was previously proposed to represent the nonlinear response of the parametric array loudspeaker (PAL), identifies the PAL as a nonlinear system that uses ultrasonic signals as its input. It has been proven that the U2VF is a more generic mod…
Volterra filters can be applied to a wide range of nonlinear systems, keeping only the low order kernels to yield a good approximation. The parametric array loudspeaker (PAL), as a weak nonlinear acoustic system, is an attractive directional sound reproduction device. Volterra filters have been adop…
A theory that predicts the behaviors of the Filtered-X LMS algorithm was derived by using a statistical-mechanical method. In this paper, the theory is generalized to explain the system behaviors in the case of an actual primary path. In the theory, cross-correlations between the element of a primar…