Apple Inc.
Directivity adjustment for reducing early reflections and comb filtering

Abstract:

A directivity adjustment device that includes a test sound signal generator, a surface detector, and a content processor is described. The test sound signal generator generates test sound signals to scan a listening area (e.g., a room) in a nodding and rotating fashion. The test sounds are emitted by one or more loudspeaker arrays and are sensed by a microphone as they permeate throughout the listening area. The sensed sound is analyzed by the surface detector, to identify reflected sounds in relation to direct sound. Based on the amplitude variance between the peaks that represent the direct and reflected sounds reaching a predefined threshold, an adjusted directivity ratio for the content processor is selected or calculated, which results in a reduction of the level of reflected sounds and corresponding comb filtering effects. Other embodiments are also described.