An acoustic chamber with low frequency outer wall transmissivity is provided. According to one aspect, an acoustic chamber has an inner wall encompassing an interior of the acoustic chamber and configured to allow acoustic energy to penetrate the inner wall. The acoustic chamber also has an outer wall configured to allow low frequency acoustic energy that penetrates the inner wall to penetrate the outer wall and leave the acoustic chamber.

An acoustic chamber with low frequency outer wall transmissivity is provided. According to one aspect, an acoustic chamber has an inner wall encompassing an interior of the acoustic chamber and configured to allow acoustic energy to penetrate the inner wall. The acoustic chamber also has an outer wall configured to allow low frequency acoustic energy that penetrates the inner wall to penetrate the outer wall and leave the acoustic chamber.

The present invention provides a sheet material having bi-directionally formed micropores, pertaining to the field of material structures. The sheet material comprises a basic half side and a protrusive half side extending from the basic half side. The basic half side is formed with multiple recesses extending along a first orientation; while the protrusive half side has multiple beams extending along a second orientation. Herein the second orientation extends at an angle with respect to the first orientation, and a bottom edge is respectively formed at the intersection of the beam and the neighboring beam; also, a hole is respectively formed at the crossing position of the bottom edge and the recess.

A building material configured to enhance sound attenuation and reduction in dB across a walled partition, the building material comprising a facing membrane, a core matrix disposed about the facing membrane, the core matrix comprising a plurality of microparticles and a binder solution configured to support the microparticles, the building material comprising at least a substantially exposed face, wherein a side of the core matrix is at least partially exposed to increase sound attenuation by reducing reflections from sound waves impinging on the building material as compared to a control building material lacking an exposed face. Two building materials may be used in conjunction with one another about a building structure, such as a stud wall, to create and define a sound trap that functions to reduce sound transmission across the partition formed by the stud wall and building materials.

An object of the present invention is to provide a structural body that has high vibration damping and high sound-insulating performance which exceeds mass law while being relatively light weight, that is highly flexible in design, excellent in versatility, and easy to manufacture so that productivity and economic efficiency can be improved. The object thereof is achieved with a sheet member of a sheet having a thickness of 1 mm or less and having rubber elasticity and a resonant portion, wherein the resonant portion is provided in contact with a surface of the sheet, the resonant portion including a base part and a weight part, and the weight part being supported by the base part and having a larger mass than the base part.

A structural body including a plurality of convex-shaped rubber-elastic resonant portions, and a sheet-like support that supports the resonant portions. A specific gravity of the resonant portions is 1.0 g/cm.sup.3 or more and 3.0 g/cm.sup.3 or less, a height of the resonant portions is from 50 m to 100 mm, and an areal density of the support is 1.0 kg/m.sup.2 or less.

A resonant sheet member containing a sheet having rubber elasticity and a resonant portion is provided. The resonant portion is in contact with a surface of the sheet and includes a base part and a weight part. The weight part is supported by the base part and a mass of the weight part is larger than a mass of the base part. The weight part is a single member, and at least a part of the weight part is embedded in the base part on leading end sides of the resonant portion. The resonant sheet member is an insert molded body.

The present invention addresses the problem of providing a sound insulating structure which provides a sufficient sound insulating effect even when an adhesive layer is arranged therein, and in which a shift in the frequency band where the sound insulating effect is generated is unlikely to occur. This sound insulating structure includes, at least: a sound insulating member that includes a sheet-like sheet section and plural projections arranged on the sheet section; and an adhesive layer arranged on a surface of the sheet section on the opposite side of the side provided with the projections, and the sound insulating structure satisfies the following Formula (1): E_glue/I_glue>0.5(E_membrane/H) (1) (wherein, E_glue (MPa): storage modulus of adhesive layer, I_glue (mm): average thickness of adhesive layer, E_membrane (MPa): storage modulus of sheet section and projections, and H (mm): average height of sheet section and projections).