A speaker box includes a housing; a speaker unit accommodated in the housing, the speaker unit including a diaphragm for vibration and sound producing; a front sound cavity formed cooperatively by the diaphragm and the housing; a sound guiding channel communicating the front sound cavity with external environment; a front cavity formed by the front sound cavity and the sound guiding channel; a through hole penetrating the housing and disposed at a position on the housing corresponding to the front cavity; and an elastic cover plate arranged on a side of the housing far from the speaker unit and covering the through hole for absorbing vibration energy at a specific frequency. A Young's modulus or strength of the elastic cover plate is smaller than that of the housing.

An acoustic protective cover assembly can include a retracted membrane material traversing across an acoustic pathway defined by an opening in a housing. The retracted membrane material can include a fibril structure characterized by serpentine fibrils.

A speaker assembly includes a sound chamber, a speaker and a diaphragm. The speaker is set at one end of the sound chamber. The diaphragm is set at one side of the sound chamber. The sound chamber, the speaker and the diaphragm form a closed cavity, thus to reduce the high tone from the speaker to a mid-bass pitch. An electronic device using the speaker assembly is also provided.

A multifunctional sound device includes a housing, a sound unit, and a motor assembly. The sound unit includes a frame, a vibration system, and a magnetic circuit system. The motor assembly includes a vibration unit and elastic components. The vibration unit includes driving coils and a mass block. The driving coils are fixed to the mass block and located in a magnetic field range of the magnetic circuit system. The mass block is made of conductive materials. The driving coils interact with the magnetic circuit system to enable the vibration unit to vibrate in a reciprocating mode after the driving coils are energized. Compared with related art, the multifunctional sound device is small in overall thickness and size, large in electromagnetic damping of a magnetic circuit, easy to assemble, and excellent in acoustic performance.

There is provided a microphone unit (1) for an action camera, comprising a microphone capsule (10) having at least one speaking hole (11), and a water-tight enclosure (20) which water-tightly encloses the microphone capsule (10). The water-tight enclosure (20) has a water-impermeable passive diaphragm (25) which can oscillate freely and which allows incoming sound to pass substantially undisturbed. The microphone unit has a head (30) having a plurality of holes (31), the head (30) being provided outside the enclosure (20) in front of the passive diaphragm (25). The microphone unit further has a foam portion (40) which is provided in front of the head (30) and has an open-pore foam. The foam portion (40) is in contact with the head (30). The passive diaphragm (25) has an oscillatable minimum area of 20 mm.sup.2; wherein the foam portion (40) has pores which are sufficiently small so that the foam portion (40) can suck water residues away from the holes (31) in the head (30) like a sponge. At the same time however the pores are of such a size that they cannot independently retain water so that water residues, after removal of the microphone unit (1) from the water, run for the greatest part out of the foam portion (40) downwardly under the effect of the force of gravity; wherein the foam portion (40) has a predominant pore density of 15 ppi to 80 ppi.

A speaker box includes a housing; a speaker unit accommodated in the housing, the speaker unit including a diaphragm for vibration and sound producing; a front sound cavity formed cooperatively by the diaphragm and the housing; a sound guiding channel communicating the front sound cavity with external environment; a front cavity formed by the front sound cavity and the sound guiding channel; a through hole penetrating the housing and disposed at a position on the housing corresponding to the front cavity; and an elastic cover plate arranged on a side of the housing far from the speaker unit and covering the through hole for absorbing vibration energy at a specific frequency. A Young's modulus or strength of the elastic cover plate is smaller than that of the housing.

In a first aspect, the invention relates to a system comprising a MEMS microphone comprising a sound inlet opening, a vibratable microphone membrane and an electronic circuit, wherein when the microphone membrane is excited by sound waves entering through the sound inlet opening, an electrical signal that is dependent on the sound waves is generated by vibrations of the microphone membrane. A damping element for reducing the sound pressure level of the sound waves acting on the microphone membrane is mounted in front of the sound inlet opening, wherein the damping element comprises an elastic and vibratable damping membrane and wherein, in addition to the microphone membrane, the damping element is induced into vibrations by the sound waves such that the sound energy of the sound waves is divided between the damping membrane and the microphone membrane. This makes it possible in particular to extend the measuring range of the MEMS microphone without distortion to high sound pressure levels that could not previously be measured with the MEMS microphones known in the prior art.

In a further aspect, the invention relates to the use of the system according to the invention for aeroacoustic measurements, preferably for measuring sound pressure waves on surfaces of a vehicle component.

A piezoelectric speaker according to one aspect of the present disclosure includes: a plurality of piezoelectric elements; a plurality of diaphragms vibrated by expansion/contraction of the plurality of piezoelectric elements, the plurality of diaphragms each having a rectangular principal surface; and a cover that has a box shape and is arranged to cover one surface of the principal surface of each of the diaphragms, the cover being arranged so that an air chamber is formed between the cover and the one surface of the principal surface of each of the diaphragms, in which the lengths of the long sides of the principal surfaces of the plurality of diaphragms are different from one another, and the cover includes an opening formed on one of surfaces of the cover perpendicular to the principal surface of each of the diaphragms.

This invention provides a kind of acoustic structure that uses passive diaphragm unit, it includes speaker unit, passive diaphragm unit, radiant tube; said passive diaphragm unit is located at the back of the cone of said speaker unit; the speaker unit has radiant tube on the sides; the said radiant tube end which is exposed in the air is located at the periphery of the cone of said speaker unit. It has the same orientation as the speaker unit; the said passive diaphragm unit vibrates when it is driven by the said speaker unit, the sound waves produced by the vibration of the said passive diaphragm unit are emitted by the radiant tube and radiant opening, and share the similar vocal point of the said speaker unit. With this, the sound effect of the full range sound is almost identical to the sound point sources, it also reduces the phase difference between the sound effects produced by the cone of speaker unit and the passive diaphragm unit, further enhanced the sound positioning feature. This invention also provides compact audio radiant module and speaker box which are designed by the structural design above.

A modular speaker includes at least an active vibrator, at least a passive vibrator, and a module housing, wherein the active vibrator and the passive vibrator are coupled to the module housing to form a vibration cavity therewithin to share with the active vibrator and the passive vibrator. When the active vibrator is operated for sound generation in response to an audio signal input, the passive vibrator is driven to vibrate through the vibration cavity for auxiliary sound generation so as to produce a point sound with full range of frequencies. The point sound with full range of frequencies produced by the modular speaker includes treble region and bass region, such that the modular speaker is able to completely restore the audio signal input as the original form to enable the listener to hear the sound quality of original raw audio signal.