Apple Inc.

Brandon J Rice

Afrooz Family

Sylvain J Choisel

Daniel C Klingler

James Hollabaugh

Ismael Hamad Nawfal

A method performed by an audio system within a room that includes a first loudspeaker that has a first beamforming array and a second loudspeaker that has a second beamforming array. The method obtains a sound program as several input audio channels. The method performs a beamforming algorithm based on the input audio channels to cause each of the arrays to produce a front beam pattern and a side beam pattern when the loudspeakers are close to an object within the room, where the front beam patterns are directed away from the object and the side beam patterns are directed towards the object and the beam patterns contain different portions of the sound program. The method performs a cross-talk cancellation (XTC) algorithm based on a subset of the input audio channels to produce several XTC output signals for driving the arrays when the loudspeakers are far away from the object.

Surround sound rendering based on room acoustics

A transition between a stereophonic presentation and a monophonic presentation of a stereophonic input signal that includes a left channel signal and a right channel signal extracts content that is present at similar levels but not in-phase between the left and right channel signals to produce at least one of a left enhancement signal and a right enhancement signal. The left channel signal, the right channel signal, and only one of the left and right enhancement signals are combined to produce a monophonic signal for the monophonic presentation. Cross-fading between the left channel signal and the monophonic signal and between the right channel signal and the monophonic signal may be used to transition between the stereophonic presentation and the monophonic presentation. The stereophonic input signal may be up-mixed to produce enhancement signal. A similar transition between a multichannel presentation and a monophonic presentation of a multichannel signal is described.

Stereophonic to monophonic down-mixing

An operating power level for a loudspeaker cabinet and a target power level for the loudspeaker cabinet are determined during output of an audio signal by the loudspeaker cabinet. The target power level is based on temperature data for the loudspeaker cabinet and varies as the temperature data changes. Based on the operating power level and the target power level, values of two or more control parameters for controlling audio output of the loudspeaker cabinet are generated, where at least one of the control parameters controls the gain of a specific audio frequency band. The audio signal is adjusted according to the generated values of the control parameters, where doing so reduces power consumption of the loudspeaker cabinet during the audio output. Other embodiments are also described.

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Pacifica, CA, United States of America

Brandon J Rice