Patent ID: 6181796
Filing Date: 2001-01-30
Classification: H03F,H04R

Abstract:
A system for generating multi-channel sound in response to input signals indicative of multiple audio channels, said system including:amplification circuitry coupled to receive the input signals, and configured to amplify the input signals with low peak current demand even when the input signals have highly correlated frequency components; anda first transducer, a second transducer, and a third transducer coupled to the amplification circuitry, said amplification circuitry comprising:first amplifier circuitry configured to receive and amplify a first one of the input signals to generate and assert at a first output node a first amplified signal, wherein the first amplifier circuitry asserts an amplified frequency component of the first amplified signal having a first phase, in response to a frequency component of the first one of the input signals having a first frequency and a first input signal phase; andsecond amplifier circuitry configured to receive and amplify a second one of the input signals to generate and assert at a second output node a second amplified signal, wherein the second amplifier circuitry asserts an amplified frequency component of the second amplified signal in response to a frequency component of the second one of the input signals having the first frequency and a phase at least substantially equal to the first input signal phase, wherein the amplified frequency component of the second amplified signal has a second phase which lags the first phase by a phase delay at least substantially equal to one-half cycle of said frequency component of the second one of the input signals, whereinthe first transducer is coupled to the first output node with a first polarity, the second transducer is coupled between the second output node and the first transducer with a polarity opposite to the first polarity so that the first transducer and the second transducer introduce a phase shift, in the amplified frequency component of the second amplified signal relative to the amplified frequency component of the first amplified signal, which cancels said phase delay, and the third transducer is coupled between the first output node and the second output node in parallel with the first transducer and the second transducer, wherein the first transducer is coupled to the second transducer at a third node, and also including a capacitor coupled between a system reference node and the third node, and wherein the first transducer radiates sound indicative of a right stereo channel in response to the first amplified signal, the second transducer radiates sound indicative of a left stereo channel in response to the second amplified signal, and the third transducer radiates sound indicative of a subwoofer channel in response to the first amplified signal and the second amplified signal.