Conventional approaches for surround sound panning require loudspeakers to be distributed over the regions where images are required. However in many listening situations it is not practical or desirable to place loudspeakers at some positions, such as behind or above the listener. Compensated Amplitude Panning (CAP) is an object-based reproduction method that adapts dynamically to the listener’s head orientation to provide stable images in any direction in the frequency range up to approximately 1000 Hz. This is achieved by accurately controlling the Interaural Time Difference cue. CAP can also provide images in the near-field range, by controlling the Interaural Level Difference. Using two loudspeakers and with full 6-degrees-of-freedom head tracking, it was previously shown possible to create low band images in any direction, although excessive gain is required for some listener orientations. But with 3 loudspeakers all images directions can be reproduced with moderate gain. Adding more loudspeakers to a stereo configuration does not worsen performance. For comparison, an Ambisonic approach with position tracking and 3 frontal loudspeakers can reproduce horizontal surround images, and 4 loudspeakers can reproduce full 3D.
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