US 5,809,150 A · Surround sound loudspeaker system

Abstract

The generation of skewed hypercardioid sound energy fields (in polar diagrams) from right front and left front "surround" loudspeakers with the principal nulls directed at the expected listener location produces the effect of sidewall and rearwall loudspeakers in a home theater setting without any actual sidewall or rearwall loudspeakers. The effect is enhanced by secondary nulls that are directed so as to "reflect" off the front wall of the room toward the expected listener location. Each surround loudspeaker contains an antiphase driver and circuitry including a delay network that powers the drivers to create the skewed hypercardioid sound energy field. The invention is independent of electrical mixing and interaction of two or more input channels. Rather the channels are assumed to be independent and the invention concerns the unique directional sound energy radiation pattern generated from each channel considered independently. An important feature of the skewed hypercardioid sound energy field according to the invention is the insensitivity of the principal null direction to frequency over a range of 120 H.sub.z to 4 kH.sub.z. Also important is a surround sound effect more pronounced in miniature (close range) speaker configurations because the energy gradient between the right and left ears is steeper with the skewed hypercardioid at close range. The invention provides a generalized method of handling direct and reflected sound in an enclosed listening space, since the parameters are variable with delay in the circuitry, the angular relationship of the drivers in the loudspeaker cabinet and the shape of the cabinet. In some listening configurations only the surround loudspeakers are necessary for superior sound reproduction.

Claims37

Dependent claims

The method of reproducing sound by creating spaced, multichannel acoustic energy sound fields generating at least two such sound fields, each comprising a substantially hypercardioid energy distribution wherein at least a first minimum of energy is located between a major lobe of energy and a minor lobe of energy, the first minimum of energy being directed toward an expected listener location and

a second minimum of energy, the second minimum of energy being directed toward an expected near sound reflective surface to cause the reflected second minimum of energy to be directed toward the expected listener location.

A composite sound radiating system comprising at least a first component sound radiating system and a second component sound radiating system, each component sound radiating system having directivity defined by at least one single major lobe of acoustic output with an axis, the two axes being directed non-parallel,

there being at least one minimum of acoustic output from the composite sound radiating system and at least one maximum of acoustic output from the composite sound radiating system,
means in communication with each sound radiating system, said means creating a delay and polarity reversal in the acoustic output of the second sound radiating system relative to the first sound radiating system and creating a difference in amplitude versus frequency response of the acoustic output of the major lobe of the second sound radiating system relative to the first sound radiating system,
whereby the amplitude of the acoustic output in the direction of maximum sound radiation from the second sound radiating system is less than the maximum amplitude of the acoustic output of the first sound radiating system and a minimum of acoustic output from the second component sound radiating system is directed substantially parallel to the major lobe axis of the first component sound radiating system.

Dependencies are inferred from the claim text.

Surround sound loudspeaker system

Life of this patent

Surround sound loudspeaker system

Life of this patent

Abstract

Claims37