US Patent 7953456 Acoustic echo reduction in mobile terminals

An electronic device includes first and second speakers, a microphone, and circuitry configured to generate first and second audio signals in response to a source audio signal, to play the first audio signal over the first speaker, and to play the second audio signal over the second speaker. The first and second audio signals are configured, and the first and second speakers are positioned, so that the first audio signal output by the first speaker and the second audio signal output by the second speaker combine destructively at the microphone.