Patents Assigned to ACOUSTIC METAMATERIALS LLC
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Patent number: 11727909Abstract: An acoustic metamaterial (AMM) passive impedance matching technique to enhance the acoustic performance of porous/poro-elastic sound absorbing materials is disclosed. An AMM passive matching device is implemented by achieving negative refractive index with double negative parameters, i.e., negative effective mass density and effective bulk modulus scheme, using various acoustic elements. The AMM technique consists of meta material architecture of acoustic inductive open tubes positioned strategically around the outside surfaces of the porous media and perforated screens inserted inside porous media to generate complex acoustic impedance load of the porous media; the inductance defined by a predetermined lengths of the open tubes. The device includes open tubes extending from the porous media to the outside ambient medium generating the desired reactive load over the broadband frequency region of the complex acoustic impedance of the porous media.Type: GrantFiled: December 26, 2022Date of Patent: August 15, 2023Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal Prasad Mathur
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Patent number: 11721314Abstract: An active acoustics management system for the loudspeaker back-enclosure, including a first loudspeaker having a front side and a back side connected by side walls, the front facing in a first direction, is presented. An enclosure surrounds a portion of the first loudspeaker, such that the enclosure is open about the front side of the first loudspeaker and is closed about the side walls and the back side of the loudspeaker. A second loudspeaker is disposed within the enclosure behind the first loudspeaker, the second loudspeaker being oriented to output waveforms in the first direction, wherein the second loudspeaker is adapted to output waveforms in the first direction thereby to cancel at least some waveforms emanating from the back side of the first loudspeaker, using active control strategies.Type: GrantFiled: October 4, 2021Date of Patent: August 8, 2023Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal Prasad Mathur
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Patent number: 11640816Abstract: An acoustic metamaterial (AMM) passive impedance matching device for headphone-type devices for matching the complex acoustic impedance load of a human ear to enhance acoustic performance of a headphone is disclosed. The device includes shunt compliance chambers stacked concentrically relative to one another from an upper end to a lower end. Each of the shunt compliance chambers includes side connecting inductive channels positioned annularly around a circumference of at least one of the shunt compliance chambers. The shunt compliance chambers define a predetermined volume of air. The inductive channels connect the shunt compliance chambers to the main headphone volume, generating an acoustic resistance and reactive impedance that matches the complex acoustic impedance load of the human ear canal. The AMM device also includes an inductive channel, as a design parameter, extending from the main headphone volume to the ambient air serving as an additional resistive and reactive load.Type: GrantFiled: May 26, 2022Date of Patent: May 2, 2023Assignee: Acoustic Metamaterials LLCInventor: Gopal Prasad Mathur
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Patent number: 11443725Abstract: An acoustic meta material (AMM) spiral device for passive amplification of sound is described. The AMM amplifier device employs at least one deep sub-wavelength spiral design with high refraction index, based on an exponential spiral shape. The AMM spiral amplifier is used to focus on low frequency sound amplification and to cover broadband frequency range. Sound emanating from a speaker travels into a spiral channel until reaching the apex of the spiral. When twin spirals are used, the sound then enters a second spiral for radiating into open air.Type: GrantFiled: February 2, 2021Date of Patent: September 13, 2022Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal P. Mathur
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Patent number: 11381905Abstract: An Acoustic meta material (AMM) device for passive amplification of sound is described. The AMM amplifier device employs a deep sub-wavelength resonator design with high refraction index, which uses resonant amplification of the bass sound. An array of sub wavelength, single frequency channels are used, each resonating and amplifying at a different frequency in the bass frequency range. This is accomplished by having many different channels, each with an opening extending in a same, common, or substantially common direction. Thus, sound emanating from a speaker in a first direction continues in this direction until reaching and entering the openings of the plurality of channels. The sound from the speaker is in all transmitted frequencies of, for example, a musical recording or the like. However, only a specific frequency and/or harmonics thereof are substantially propagated through each channel.Type: GrantFiled: July 26, 2018Date of Patent: July 5, 2022Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal P. Mathur
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Patent number: 11323798Abstract: An acoustic metamaterial passive impedance matching device for use in matching the acoustic impedance of a loudspeaker is disclosed. The device includes a baffle having an upper end and a lower end, plates stacked concentrically from the upper end to the lower end, slots positioned between the plates, a side channel extending annularly around a circumference of at least one of the plates, and a spoke interconnecting the plates. Each of the plates includes a central region including perforations. Each of the slots is positioned between two adjacent plates. The side channel defines a chamber including a height greater than the height of the plates and an interior volume enclosing a predetermined volume of air. The side channels and the perforated plates generate an acoustic impedance that matches the complex conjugate acoustic impedance of the loudspeaker to deliver maximum acoustic power. The side channels may include open ends, closed ends, or both for providing an inductive or reactive capacitance.Type: GrantFiled: December 1, 2021Date of Patent: May 3, 2022Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal P. Mathur
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Patent number: 11289786Abstract: A metamaterial loudspeaker diaphragm is disclosed. The diaphragm includes a cone structure having a periodic arrangement of two dissimilar materials, e.g., soft and hard, in an alternating periodic pattern to achieve an anisotropic structure, which results in passive amplification of the sound. The anisotropic cone structure includes a baseline cone material and a different, compatible second material. The cone includes a body having a conical cross-section, an interior side, an exterior side, and concentric circles of material alternating between a soft material and a rigid material. Circumferential grooves disposed within the concentric circles include rigid material. Concentric circles including rigid material line the interior side of the body. Substantially all the soft material of the concentric circles is disposed on the exterior side of the cone. Spokes disposed on the exterior side of the cone extend from a base toward a vertex of the cone.Type: GrantFiled: July 3, 2020Date of Patent: March 29, 2022Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal P. Mathur
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Patent number: 11172288Abstract: An active acoustics management system for the loudspeaker back-enclosure, including a first loudspeaker having a front side and a back side connected by side walls, the front facing in a first direction, is presented. An enclosure surrounds a portion of the first loudspeaker, such that the enclosure is open about the front side of the first loudspeaker and is closed about the side walls and the back side of the loudspeaker. A second loudspeaker is disposed within the enclosure behind the first loudspeaker, the second loudspeaker being oriented to output waveforms in the first direction, wherein the second loudspeaker is adapted to output waveforms in the first direction thereby to cancel at least some waveforms emanating from the back side of the first loudspeaker, using active control strategies.Type: GrantFiled: May 31, 2021Date of Patent: November 9, 2021Assignee: Acoustic Metamaterials LLCInventor: Gopal Prasad Mathur
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Patent number: 10950212Abstract: An acoustic meta material (AMM) spiral device for passive amplification of sound is described. The AMM amplifier device employs at least one deep sub-wavelength spiral design with high refraction index, based on an exponential spiral shape. The AMM spiral amplifier is used to focus on low frequency sound amplification and to cover broadband frequency range. Sound emanating from a speaker travels into a spiral channel until reaching the apex of the spiral. When twin spirals are used, the sound then enters a second spiral for radiating into open air.Type: GrantFiled: February 25, 2020Date of Patent: March 16, 2021Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal P. Mathur
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Patent number: 10735851Abstract: An Acoustic meta material (AMM) device for passive amplification of sound is described. The AMM amplifier device employs a deep sub-wavelength resonator design with high refraction index, which uses resonant amplification of the bass sound. An array of sub wavelength, single frequency channels are used, each resonating and amplifying at a different frequency in the bass frequency range. This is accomplished by having many different channels, each with an opening extending in a same, common, or substantially common direction. Thus, sound emanating from a speaker in a first direction continues in this direction until reaching and entering the openings of the plurality of channels. The sound from the speaker is in all transmitted frequencies of, for example, a musical recording or the like. However, only a specific frequency and/or harmonics thereof are substantially propagated through each channel.Type: GrantFiled: March 6, 2020Date of Patent: August 4, 2020Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal P. Mathur
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Patent number: 10701478Abstract: A meta acoustic horn (MAHI) device for passive amplification of sound is described. The MAH audio amplifier device employs a deep sub-wavelength acoustic meta material horn design with high refraction index, which provides amplification of the sound over large audio frequency range. An array of sub-wavelength, zig-zag channels, contained in a horn-like micro channel is devised, to achieve amplification of sound. This is accomplished by varying the width and port opening of the channel in a fixed ratio, called MAH ratio, opening extending in a same, common, or substantially common direction. The sound emanating from a speaker enters the opening of the MAH channel and comes out amplified at the output port. The sound from the speaker is in all transmitted frequencies of, for example, a musical recording or the like. All frequencies of the original sound thereof are substantially propagated through the MAH channel, and are amplified.Type: GrantFiled: June 19, 2019Date of Patent: June 30, 2020Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal Prasad Mathur
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Patent number: 10616679Abstract: An Acoustic meta material (AMM) device for passive amplification of sound is described. The AMM amplifier device employs a deep sub-wavelength resonator design with high refraction index, which uses resonant amplification of the bass sound. An array of sub wavelength, single frequency channels are used, each resonating and amplifying at a different frequency in the bass frequency range. This is accomplished by having many different channels, each with an opening extending in a same, common, or substantially common direction. Thus, sound emanating from a speaker in a first direction continues in this direction until reaching and entering the openings of the plurality of channels. The sound from the speaker is in all transmitted frequencies of, for example, a musical recording or the like. However, only a specific frequency and/or harmonics thereof are substantially propagated through each channel.Type: GrantFiled: May 20, 2019Date of Patent: April 7, 2020Assignee: ACOUSTIC METAMATERIALS LLCInventor: Gopal P. Mathur