ABSTRACT
Broadband time-invariant feedback (FB) controllers can be designed to cancel unwanted noise components with a single error microphone on each side of a headphone. This paper presents an optimization routine based on the genetic algorithm (GA) approach to set the boundaries for a mixed-sensitivity H∞ controller. The FB controllers are designed with the different target functions, sound pressure level (SPL), perceived loudness and perceived sharpness based on test signals with different spectral characteristics. The optimization for loudness and SPL shows proper results, while the optimization for sharpness can only be recommended to a limited extent.
Subject(s)
Noise , Feedback , Noise/adverse effects , PsychoacousticsABSTRACT
It is well known that reverberation plays an important role in perceived externalization of three-dimensional audio over headphones. In the case of the externalization of a frontal sound source, the reverberation heard by both ears is equally important. Relatively little is known about the relative influence of reverberation at the contralateral versus the ipsilateral ear on perceived externalization of a lateral sound source. For a lateral sound source, the direct sound energy is much higher at the ipsilateral ear than at the contralateral ear due to the shadowing effect, which dominates at mid to high frequencies. The reverberant energy does not have a major difference between two ears. Therefore, the direct-to-reverberant energy ratio is much lower for the contralateral ear than for the ipsilateral ear. In addition, the frequency-to-frequency variability, which describes the frequency variability in the magnitude spectrum, is more pronounced in the contralateral ear than in the ipsilateral ear. The results of two listening experiments and the analysis of short-term binaural cues suggested that the reverberation at the contralateral ear has more influence on perceived externalization of a lateral sound source than that at the ipsilateral ear.
