Provided is a soundproof structure that is small and light and can reduce noise with a high natural frequency of a sound source at a plurality of frequencies at the same time. The soundproof structure according to the embodiment of the present invention includes a plurality of membrane-like members that are overlapped to be spaced from each other, a support that is made of a rigid body and supports each of the plurality of membrane-like members so as to perform membrane vibration, an inter-membrane space that is sandwiched between two adjacent membrane-like members among the plurality of membrane-like members, and a rear surface space that is formed between one membrane-like member at one end of the support in the support among the plurality of membrane-like members and the one end of the support, in which each of the plurality of membrane-like members absorbs a sound by performing the membrane vibration in a state where the one end of the support is closed.

A speaker device incorporating acoustic meta materials for sound diffraction reduction wherein the meta materials have a plurality of channels to dampen sound waves. Meta materials are applied to the speaker unit, serve as structural components of a speaker baffle, waveguide, and/or cone. The meta materials have openings in them to permit sound waves to enter and positioned at the edges of the speaker cabinet to prevent sound waves from re-radiating and interfering with the sound waves intended for the listener.

A speaker device incorporating acoustic meta materials for sound diffraction reduction wherein the meta materials have a plurality of channels to dampen sound waves. Meta materials are applied to the speaker unit, serve as structural components of a speaker baffle, waveguide, and/or cone. The meta materials have openings in them to permit sound waves to enter and positioned at the edges of the speaker cabinet to prevent sound waves from re-radiating and interfering with the sound waves intended for the listener.

A sound isolation device includes at least one degenerate acoustic scatterer having a plurality of channels. The plurality of channels may include three or more channels. The channels have an open end and a terminal end, wherein the terminal ends of the channels are separate from one another. The at least one degenerate acoustic scatterer has an acoustic monopole response and an acoustic dipole response that have a substantially similar resonant frequency.

A glass wool panel, intended to be used as an acoustic panel, has a density of less than or equal to 130 kg/m.sup.3, an air flow resistivity of between 30 and 120 kPa.Math.s/m.sup.2, a Young's modulus of between 0.5 and 4 MPa.

A glass wool panel, intended to be used as an acoustic panel, has a density of less than or equal to 130 kg/m.sup.3, an air flow resistivity of between 30 and 120 kPa.Math.s/m.sup.2, a Young's modulus of between 0.5 and 4 MPa.

An exhaust device (108) for a vehicle is provided. The exhaust device (108) includes an outer shell (202), an inlet (206) to receive exhaust gases, an outlet (208), an inner shell (204) received within the outer shell (202), a pair of partition walls (216) and a Helmholtz neck (220). The inner shell (204) defines an inner volume (210). A plurality of first circumferential openings (212) extending through the inner shell (204) fluidly communicates the inlet (206) with the inner volume (210). A plurality of second circumferential openings (214) extending through the inner shell (204) fluidly communicates the outlet (208) with the inner volume (210). The pair of partition walls (216) is disposed between the inner shell (204) and the outer shell (202). The pair of partition walls (216), the inner shell (204) and the outer shell (202) define a Helmholtz chamber (218) therebetween. The partition walls (216) seal the Helmholtz chamber (218) from the inlet (206) and the outlet (208). The Helmholtz neck (220) is disposed on the inner shell (204) or one of the pair of partition walls (216).

An exhaust device (108) for a vehicle is provided. The exhaust device (108) includes an outer shell (202), an inlet (206) to receive exhaust gases, an outlet (208), an inner shell (204) received within the outer shell (202), a pair of partition walls (216) and a Helmholtz neck (220). The inner shell (204) defines an inner volume (210). A plurality of first circumferential openings (212) extending through the inner shell (204) fluidly communicates the inlet (206) with the inner volume (210). A plurality of second circumferential openings (214) extending through the inner shell (204) fluidly communicates the outlet (208) with the inner volume (210). The pair of partition walls (216) is disposed between the inner shell (204) and the outer shell (202). The pair of partition walls (216), the inner shell (204) and the outer shell (202) define a Helmholtz chamber (218) therebetween. The partition walls (216) seal the Helmholtz chamber (218) from the inlet (206) and the outlet (208). The Helmholtz neck (220) is disposed on the inner shell (204) or one of the pair of partition walls (216).

A Helmholtz resonator having a plurality of resonator chamber modules formed into an array. The array is configured to dampen sound. A module of the plurality of resonator chamber modules includes a first chamber and a second chamber. The first and second chambers have different lengths and are tuned to dampen different frequencies of sound.

A Helmholtz resonator having a plurality of resonator chamber modules formed into an array. The array is configured to dampen sound. A module of the plurality of resonator chamber modules includes a first chamber and a second chamber. The first and second chambers have different lengths and are tuned to dampen different frequencies of sound.