Inverse filter design for immersive audio rendering over loudspeakers

Abstract

Immersive audio systems can be used to render virtual sound sources in three-dimensional (3-D) space around a listener. This is achieved by simulating the head-related transfer function (HRTF) amplitude and phase characteristics using digital filters. In this paper, we examine certain key signal processing considerations in spatial sound rendering over headphones and loudspeakers. We address the problem of crosstalk inherent in loudspeaker rendering and examine two methods for implementing crosstalk cancellation and loudspeaker frequency response inversion in real time. We demonstrate that it is possible to achieve crosstalk cancellation of 30 dB using both methods, but one of the two (the Fast RLS Transversal Filter Method) offers a significant advantage in terms of computational efficiency. Our analysis is easily extendable to nonsymmetric listening positions and moving listeners.Index Terms-Crosstalk cancellation, head-related transfer function, 3-D audio signal processing.

From remote media immersion to Distributed Immersive Performance

“…Accurate spatial reproduction of sound relative to visual images is essential for DIP, e.g., in rendering musical instruments being played or a singer's voice. Even a slight mismatch between the aurally-perceived and visually-observed positions of a sound causes a cognitive dissonance that can destroy the carefully-planned suspension of disbelief [20], [22]. To minimize latency, we are developing new audio acquisition methods that: place microphones very close to the participants (a few meters) and reduce the analog-to-digital conversion, packetizing and transmission time to less than 10 ms. Current standard recording techniques place microphones at a longer distance to the performers such that the ambient acoustics of, for example, a concert hall are captured in addition to the direct sound from the instruments.…”

Virtual Audio Systems

“…As a result, its effectiveness is limited by the variability in size and shape of the human head and pinna (Gardner, 1998). The technique also has a small listener sweet spot; to function properly, the listener must remain stationary in the sweet spot because head movements as small as 74 -100 mm completely destroy the desired effect (Mouchtaris, Reveliotis, & Kyriakakis, 2000). As with headphone-based systems, this problem can be significantly reduced by tracking the listener's head.…”

“…Gardner's system offers improved localization over nontracked loudspeaker displays because it allows for dynamic localization cues. Mouchtaris et al (2000) describe a loudspeaker-based three-dimensional audio display that produces dynamic crosstalk cancelation using a camera-based head tracking system, thus eliminating the tether associated with magnetic trackers.…”

Intelligent Acoustic Interfaces With Multisensor Acquisition for Immersive Reproduction

“…For this purpose, immersive communication is not limited to recreate the remote sound field accurately, but it involves a perceptual reproduction of the desired acoustic information [1]. In this context, a fundamental role is played by the processing techniques of acoustic information [2] and its reproduction under the fulfillment of quality requirements demanded by users [3]. This is the reason why acoustic interfaces can be equipped with acoustic signal processors, giving rise to intelligent acoustic interfaces (IAIs) [4], [5].…”