A damped propshaft assembly with a hollow shaft and a tuned damper, which is received in the hollow shaft and includes a liner and a damping member. The liner's mass and stiffness are tuned to attenuate one or more of a bending mode vibration and a torsion mode vibration that occurs at a first predetermined frequency. The liner is not configured to substantially damp shell mode vibration that occurs at a frequency that is not equal to the first predetermined frequency. The damping member is coupled to the liner and is configured to primarily attenuate shell mode vibration in the hollow shaft at one or more desired frequencies. The tuned damper attenuates the at least one of the bending moment vibration and the torsion mode vibration at the first predetermined frequency and also attenuates shell mode vibration. A method for forming a damped propshaft assembly is also provided.

The present disclosure involves a method and apparatus for attaching two electrical dies by wire bonding and then encasing the assembly in a protective casting that works by arranging two dies into a fixture conducive to wire bonding. Doped epoxy may be immediately dispensed over the assembly to form a near-net-shape protective cover, or Drive Can.

An acoustic tile used for a modular wall system includes a substrate layer having a plurality of holes that extend at least partially through the substrate layer, and a veneer layer having a plurality of microholes extending at least partially therethrough. The two layers are attached together and configured for attachment to a frame of a modular wall system such that they provide desired acoustic properties to the modular wall system.

A speaker and a method of producing a speaker, the speaker including: an enclosure; at least one transducer mounted in the enclosure; and at least one passive radiator mounted in the enclosure, including a suspension and a center panel encircled by and adhered to the suspension, wherein the at least one transducer is combined with the at least one passive radiator, and functions as at least a part of the center panel. According to the speaker of the present disclosure, by fully or partly replacing the center panel of the at least one passive radiator by one or more transducer(s), both the internal space and the cost of the speaker are saved without sacrificing the sound quality.

Systems and methods for enhancing performance of a microphone are disclosed. An airflow control system may include a block-shaped structure and an airflow impedance element residing within a cavity of the block-shaped structure. The airflow impedance element may be formed by filling the cavity with a plurality of pre-processed airflow impedance elements and sintering these elements, and may include a plurality of non-linear pathways. The plurality non-linear pathways may both impede airflow therethrough (e.g., when a force exerted by the airflow exceeds a predetermined amount) and pass sound that may match a frequency response of a microphone without substantially affecting the amplitude and frequency characteristics of the sound.

A device for elastic guidance in rotation for a timepiece mechanism allows rotation of one element relative to another element about an axis of rotation Z defining an axial direction. The device includes construction blades that each includes an assembly fixing part having a body and a functional part extending from the body as far as one end. The assembly fixing part and the functional part are separated by at least one slot in at least two extensions which are elastically connected and extend in a radial direction transverse to the axial direction. The device also includes anchorage zones which are disposed at opposite axial ends of the flexible guidance device, and configured to be fixed to the elements.

Methods for fabricating layered appliances are provided. In some embodiments, a method includes generating a digital model of a polymeric shell including a plurality of tooth-receiving cavities shaped to receive and reposition a patient's teeth from a first arrangement toward a second arrangement. The polymeric shell can include an interior layer having a first stiffness, and an exterior layer having a second stiffness greater than the first stiffness. The exterior layer can include a discontinuity formed therein. The method can further include transmitting the digital model to a fabrication system configured to fabricate the polymeric shell based on the digital model.