A calibration method allowing users to customize the loudspeaker layout for 2-, 4-, and 5.1-channel playback, and to steer the “sweet spot” to the position o f the listener’s head is presented. The method, which is applied to a computationally efficient transaural 3D audio system for dynamic spatialization o f multiple sound sources, is based on u ser interaction and auditory feedback. The robustness of the a uditory sensation is analyzed for small displacements of the listener near the sweet spot. A modification of the system permits continuous adjustment of the sweet spot size by the listener. The modification limits the a rtifacts due to the transaural processing for positions away from the sweet spot. For wide settings, the system gradually reduces to a discrete amplitude panning system.

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Artificial reverberator topologies making use of all-pass filters in a feedback loop are popular, but have lacked accurate control of decay time and energy level. This paper reviews a general theory of artificial reverberators based on Unitary-Feedback Delay Networks (UFDN), which allow accurate control of the decay time at multiple frequencies in such topologies. We describe the design of an efficient reverberator making use of chains of elementary filters, called “absorbent all-pass filters”, in a feedback loop. We show how, in this particular topology, the late reverberant energy level can be controlled independently of the other control parameters. This reverberator uses the I3DL2 control parameters, which have been designed as a standard interface for controlling reverberators in interactive 3D audio.

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