A method for feedforward noise cancellation in an enclosed space within a structure is provided. The method comprises placing a microphone array inside an inner surface of the enclosed space and conducting modal testing on an outside surface of the enclosed space, wherein the modal testing comprises multiple incoherent noise sources corresponding to locations of microphones in the microphone array. Noise generated by the modal testing is processed to create a number of acoustic mathematical models of the enclosed space. In response to incoherent noise within the enclosed space, a noise canceling signal is generated according to an output of the mathematical models.

In one embodiment of an audio system, a transducer can be coupled to a passive acoustic directional amplifier to provide various benefits and improvements, including improvements to: speech intelligibility, signal-to-noise ratio, effective equivalent input noise, at-a-distance acoustic signal reception, and directional preference. In another embodiment, the shape of an interior surface of a passive acoustic directional amplifier is provided. In another embodiment, the material properties of an interior surface of a passive acoustic directional amplifier are provided.

An integrated circuit includes a first amplifier and a second amplifier. A first impedance matching circuit is coupled to the first amplifier, a first charge pump, and a single MEMS transducer. A second impedance matching circuit is coupled to the second amplifier, a second charge pump, and to the single MEMS transducer. A first capacitive load as measured at an input of first amplifier, and a second capacitive load as measured at an input of the second amplifier exist. The first capacitive load and the second capacitive load are balanced with respect to each other. A single pressure change causes the single MEMS transducer to create a first electrical signal and a second electrical signal. Both the first electrical signal and the second electrical signal are matched or approximately matched in magnitude, and 180 degrees or approximately 180 degrees out of phase with respect to each other.

A condenser microphone with at least two microphone capsules, each including a diaphragm and a backplate. The backplates of both the first capsule and second capsule having an electret bias. The first capsule having a first polar pattern, and the second capsule having a second polar pattern. The second capsule having an external voltage bias that is continuously variable over a certain voltage range. This external voltage bias can be applied to the second diaphragm or second backplate. The microphone's total polar pattern consists of a combination of the first polar pattern and the second polar pattern. Using the external voltage bias of the second capsule, the microphone's total polar pattern is continuously variable throughout a range set by the external voltage bias.

A microphone includes a tubular case having a bottom surface, a side surface and an opened top, a substrate which is fixed so as to block an opening portion of the opened top of the case, and has an electrode portion on an upper surface thereof, and a side-surface sound hole formed in the side surface of the case.

Charged polymeric webs, such as electret webs, include a thermoplastic resin and a charge-enhancing additive. The additives are substituted heterocyclic thiolate salts. The heterocyclic thiolate salt has 2 nitrogen groups and a third group that may be an NH, N—NH.sub.2, O, or S group. The substituent group is an aromatic or heterocyclic aromatic group. The electret webs may be a non-woven fibrous web or a film. The electret webs are suitable for use as filter media.

A device includes a housing, an acoustic sensor disposed within the housing, the acoustic sensor comprising a microelectrornechanical (MEMS) transducer, a first port in the housing establishing a first acoustic path for air flow to the MEMS transducer, and a second port in the housing establishing a second acoustic path for air flow to the MEMS transducer. The first and second acoustic paths have an equal path length.

Certain embodiments provide a hearing test probe apparatus including a hearing test probe, an eartip, and a microphone. The probe includes a speaker disposed within a probe body, and a mounting stem extending from the probe body and including a speaker sound channel. The eartip is detachably coupled to the mounting stem, and includes an eartip body having an ear insertion end and a probe insertion end opposite the ear insertion end. The eartip body defines a central opening extending from the ear insertion end to the probe insertion end. The central opening includes an eartip sound channel at the ear insertion end and an eartip mounting portion at the probe insertion end. The eartip mounting portion is configured to receive and hold the mounting stem of the probe within the central opening. The microphone is disposed within the eartip when the eartip is detachably coupled to the mounting stem.

A device, including an implantable microphone, including a transducer, and a chamber in which a gas is located such that vibrations originating external to the microphone based on sound are effectively transmitted therethrough, wherein the transducer is in effective vibration communication with the gas, wherein the transducer is configured to convert the vibrations traveling via the gas to an electrical signal, the chamber and the transducer correspond to a microphone system, wherein the chamber corresponds to a front volume of the microphone system, and the transducer includes a back volume corresponding to the back volume of the microphone system, and the implantable microphone is configured to enable pressure adjustment of the front and/or back volume in real time.

A vibration transducer for sensing vibrations includes a first flexible triboelectric member, a second flexible triboelectric member, a plurality of attachment points, a first electrode and a second electrode. The first flexible triboelectric member includes a first triboelectric layer and a material being on a first position on a triboelectric series. A conductive layer is deposited on the second side thereof. The second flexible triboelectric member includes a second triboelectric layer and a material being on a second position on the triboelectric series that is different from the first position on the triboelectric series. The second triboelectric member is adjacent to the first flexible triboelectric member. When the first triboelectric member comes into and out of contact with the second triboelectric member as a result of the vibrations, a triboelectric potential difference having a variable intensity corresponding to the vibrations can be sensed between the first and second triboelectric members.