Patent ID: 8175304

Claim:
An apparatus configured to reproduce sound audible to humans, the apparatus comprising: an array of speaker drivers comprising a front-facing speaker driver, a rear-facing speaker driver, a left-facing speaker driver, and a right-facing speaker driver, wherein each of the front-facing speaker driver, the rear-facing speaker driver, the left-facing speaker driver, and the right-facing speaker driver is generally facing outward, wherein the front-facing speaker driver, the rear-facing speaker driver, the left-facing speaker driver, and the right-facing speaker driver are mounted in a single chassis; and a circuit configured to drive the front-facing speaker driver with a mid channel signal comprising a sum of a left channel signal and a right channel signal, wherein the circuit is configured to drive the rear-facing speaker driver with a signal having the same content as the mid channel signal, wherein the circuit is configured to drive the left-facing speaker driver at least partially with a side channel signal comprising a difference between the left channel signal and the right channel signal, and wherein the circuit is configured to drive the right-facing speaker driver such that the right-facing speaker driver has side channel signal content that is out-of-phase with respect to the left-facing speaker driver.