Patent Description:
Headphones may include active noise reduction, also known as active noise control (ANC). Generally, noise reduction may be classified as feedback noise reduction or feedforward noise reduction or a combination thereof. In a feedback noise reduction system a microphone is positioned in an acoustic path that extends from a noise source to the ear of a user. A speaker is positioned between the microphone and the noise source. Noise from the noise source and anti-noise emitted from the speaker are collected by the microphone and, based on the residual noise thereof, the anti-noise is controlled to reduce the noise from the noise source. In a feedforward noise reduction system, a microphone is positioned between the noise source and the speaker. The noise is collected by the microphone, is inverted in phase and is emitted from the speaker to reduce the external noise. In a combined feedforward/feedback (hybrid) noise reduction system, a first microphone is positioned in the acoustic path between the speaker and the ear of the user. A second microphone is positioned in the acoustic path between the noise source and the speaker and collects the noise from the noise source. The output of the second microphone is used to make the transmission characteristic of the acoustic path from the first microphone to the speaker the same as the transmission characteristic of the acoustic path along which the noise from the noise source reaches the user's ear. The speaker is positioned between the first microphone and the noise source. The noise collected by the first microphone is inverted in phase and emitted from the speaker to reduce the external noise.

Publication <CIT> discloses a personal listening device with an earphone housing and at least one reference microphone and an error microphone installed therein. The reference microphone may be installed on the exterior of the housing or at least one reference microphone may be located within the housing to pick up noise that is external to the personal listening device. In the embodiment where a plurality of reference microphones are included in the personal listening device, the plurality of reference microphones can form one or more microphone arrays that may be used to create microphone array beams. The beams can be steered to a given direction, e.g., towards the primary noise source or in other given directions. Publication <CIT> discloses a system that calculates, based on phase differences between corresponding frequency components of different channels of a multichannel signal, a measure of directional coherency, which is applicable in voice activity detection and noise reduction. Publication <CIT> discloses a hearing assistance system that includes an adaptive directionality controller to control a target direction for sound reception. The adaptive directionality controller includes a beamformer, a speech detector to detect off-axis speech being speech that is not from the target direction, and a steering module to steer the beamformer in response to a detection of the off-axis speech. Publication <CIT> discloses a hearing device in which the direction of a directional microphone is selectable based on signal-to-noise ratios so that the directional microphone is switched into that one of two directional characteristics which leads to the higher signal-to-noise ratio. It is desired to improve the known headphones in order to reduce the noise emitted by a multiplicity of noise sources from a multiplicity of directions.

An active noise reducing earphone includes a rigid cup shell having an inner surface and an outer surface, the inner surface encompassing a cavity with an opening, and includes a microphone arrangement configured to pick up sound with at least one steerable beam directivity characteristic, and to provide a first electrical signal that represents the picked-up sound. The earphone further includes an active noise control filter configured to provide, based on the first electrical signal, a second electrical signal, and includes a speaker disposed in the opening of the cavity and configured to generate sound from the second electrical signal. The active noise control filter has a transfer characteristic that is configured so that noise that travels through the shell from beyond the outer surface to beyond the inner surface is reduced by the sound generated by the speaker. The microphone arrangement includes an array of multiple microphones, the multiple microphones being distributed over the outer surface of the shell, and a beamformer block electrically connected to the array of multiple microphones and configured to provide in connection with the array of multiple microphones, a directivity characteristic of the array of multiple microphones that includes at least one beam. The microphone arrangement is configured to provide an awareness mode of operation in which one or more beams are steered in different directions and to evaluate a signal-to-noise ratio of each beam, a direction in which one beam thereof having a highest signal-to-noise ratio is selected as a direction of a desired-sound source. The active noise control filter is deactivated in the awareness mode while the one beam with the highest signal-to-noise ratio is selected as the direction of the desired-sound source.

An active noise reducing method for an earphone is disclosed, the earphone having a rigid cup shell having an inner surface and an outer surface. The inner surface encompasses a cavity with an opening. The method includes picking up sound with at least one steerable beam directivity characteristic, and providing a first electrical signal that represents the picked-up sound, filtering the first electrical signal to provide a second electrical signal, and generating in the opening of the cavity, sound from the second electrical signal. Filtering is performed with a transfer characteristic that is configured so that noise that travels through the shell from beyond the outer surface to beyond the inner surface is reduced by the sound generated in the opening, and beamforming is based on multiple sound signals from an array of multiple microphones distributed over the outer surface of the shell. The beamforming is configured to provide a directivity characteristic of the array of multiple microphones that includes at least one beam, and the array of multiple microphones is distributed over the outer surface of the shell. Beamforming comprises an awareness mode of operation in which one or more beams are steered in different directions and to evaluate a signal-to-noise ratio of each beam. A direction in which the beam thereof having a highest signal-to-noise ratio is selected as a direction of a desired-sound source. The method further includes deactivating, in the awareness mode, the filtering that is performed with the transfer characteristic while the beam with the highest signal-to-noise ratio is selected as the direction of the desired-sound source.

Other systems, methods, features and advantages will be, or will become, apparent to one with skill in the art upon examination of the following detailed description and appended figures. It is intended that all such additional systems, methods, features and advantages be included within this description.

The system may be better understood with reference to the following drawings and description. In the figures, like referenced numerals designate corresponding parts throughout the different views.

<FIG> is a simplified illustration of an exemplary feedback type active noise control (ANC) earphone <NUM> (e.g., as part of a headphone with two earphones). An acoustic path (also referred to as channel), represented by a tube <NUM>, is established by the ear canal, also known as external auditory meatus, and parts of the earphone <NUM>, into which noise, i.e., primary noise <NUM>, is introduced at a first end <NUM> from a noise source <NUM>. The sound waves of the primary noise <NUM> travel through the tube <NUM> to the second end <NUM> of the tube <NUM> from where the sound waves are radiated, e.g., to the tympanic membrane of an ear <NUM> of a user when the earphone <NUM> is attached to the user's head. In order to reduce or even cancel the primary noise <NUM> in the tube <NUM>, a sound radiating transducer, e.g., a speaker <NUM>, introduces cancelling sound <NUM> into the tube <NUM>. The cancelling sound <NUM> has an amplitude corresponding to or being the same as the primary noise <NUM>, however, of opposite phase. The primary noise <NUM> which enters the tube <NUM> is collected by an error microphone <NUM> and is processed by a feedback ANC processing module <NUM> to generate a cancelling signal and then emitted by the speaker <NUM> to reduce the primary noise <NUM>. The error microphone <NUM> is arranged downstream of the speaker <NUM> and thus is closer to the second end <NUM> of the tube <NUM> than to the speaker <NUM>, i.e., it is closer to the ear <NUM>, in particular to its tympanic membrane.

<FIG> is a simplified illustration of an exemplary feedforward type ANC earphone <NUM>. The earphone <NUM> includes a microphone <NUM> that is arranged between the first end <NUM> of the tube <NUM> and the speaker <NUM>, e.g., as close as possible to the noise source <NUM>. Furthermore, a feedforward ANC processing module <NUM> is connected between the microphone <NUM> and speaker <NUM>. The feedforward ANC processing module <NUM> as shown may be, for example, a non-adaptive filter, i.e., a filter with fixed transfer function. Alternatively the feedforward ANC processing module <NUM> may be adaptive (e.g., an adaptive filter) in connection with an additional error microphone <NUM> which is disposed between the speaker <NUM> and the second end <NUM> of the tube <NUM> (e.g., as close as possible to the ear <NUM>) and which controls the transfer function of the feedforward ANC processing module <NUM>. Further, a non-acoustic sensor (not shown) may be employed instead of the reference microphone <NUM>.

<FIG> is a simplified illustration of an exemplary hybrid type ANC earphone <NUM>. A feedforward microphone <NUM> senses the primary noise <NUM> close to the noise source <NUM> and its output is supplied to a hybrid ANC processing module <NUM>. The primary noise <NUM> and sound radiated from the speaker <NUM> are sensed close to the ear <NUM> by a feedback microphone <NUM> whose output is also supplied to the hybrid ANC processing module <NUM>. The hybrid ANC processing module <NUM> generates a noise reducing signal which is emitted by the speaker <NUM> disposed between the two microphones <NUM> and <NUM>, thereby reducing the undesirable noise at the ear <NUM>.

Referring to <FIG>, an exemplary hybrid noise reducing system (e.g., applicable in the hybrid type ANC earphone <NUM> shown in <FIG>) includes a first microphone <NUM> that senses at a first location a noise signal from, e.g., a noise source <NUM>, and that is electrically coupled to a first microphone output path <NUM>. A loudspeaker <NUM> is electrically coupled to a loudspeaker input path <NUM> and radiates noise reducing sound at a second location. A second microphone <NUM> that is electrically coupled to a second microphone output path <NUM> picks up residual noise at a third location, the residual noise being created by superimposing the noise received via a primary path <NUM> and the noise reducing sound received via a secondary path <NUM>. A first (feedforward) active noise reducing filter <NUM> is connected between the first microphone output path <NUM> and via the adder <NUM> to the loudspeaker in-put path <NUM>. A second (feedback) active noise reducing filter <NUM> is connected to the second microphone output path <NUM> and via an adder <NUM> to the loudspeaker input path <NUM>. The second active noise reduction filter <NUM> is or comprises at least one shelving or equalization (peaking) filter. These filter(s) may have, for instance, a 2nd order filter structure. The active noise reducing filters <NUM> and <NUM> can be implemented in any analog or digital filter structure, e.g., as digital finite impulse response filters.

In the system of <FIG>, an open loop <NUM> and a closed loop <NUM> are combined, forming a so-called "hybrid" system. The open loop <NUM> includes the first microphone <NUM> and the first ANC filter <NUM>. The closed loop <NUM> includes the second microphone <NUM> and the second ANC filter <NUM>. First and second microphone output paths <NUM> and <NUM> and the loudspeaker input path <NUM> may include analog amplifiers, analog or digital filters, analog-to-digital converters, digital-to-analog converters or the like which are not shown for the sake of simplicity. The first ANC filter <NUM> may be or may comprise at least one shelving or equalization filter.

The shelving or equalizing filter of the first ANC filter may be an active or passive analog filter or a digital filter. The shelving filter in the second ANC filter may be an active or passive analog filter. For instance, the first ANC filter may be or may comprise at least one digital finite impulse response filter.

The system shown in <FIG> has a sensitivity which can be described by the equation: <MAT> in which H(z) is the transfer characteristic of the primary path <NUM>, WOL(z) is the transfer characteristic of the first ANC filter <NUM>, SCL(z) is the transfer characteristic of the secondary path <NUM>, and WCL(z) is the transfer characteristic of the second ANC filter <NUM>. Advantageously, the first ANC filter <NUM> (closed loop) and the second ANC filter <NUM> (closed loop) can easily be optimized separately.

In theory, feedforward ANC system are very effective and easy to implement, since the optimal filter (WOL(z)), in contrast to feedback ANC system, can be directly calculated by the ratio of the primary path (H(z)) to the secondary path (SCL(z))-WOL(z)=H(z)/SCL(z)). While the secondary path in headphone applications more or less remains the same, this is, unfortunately not the case for the primary path. Depending on the noise source, the primary path will dynamically change, leading to a somewhat unpredictable ANC performance of feedforward systems. One way to overcome this backlog is, e.g., to place the open loop (OL), which is the outside mounted microphone of the headphone, mechanically steerable and at a certain distance from the outer shell of each earphone.

The examples shown in <FIG> are not according to the invention and are presented for illustration purposes only. In an exemplary earphone <NUM> (e.g., as part of a feedfoward ANC headphone with two earphones) shown in <FIG> , a rigid cup-like shell <NUM> has an inner, e.g., convex surface <NUM>, and an outer, e.g., concave surface <NUM> which encompasses a cavity <NUM> with an opening <NUM>. An electro-acoustic transducer for converting electrical signals into sound, such as a speaker <NUM>, is disposed in the opening <NUM> of the cavity <NUM> and generates sound from an electrical signal provided by an active noise control filter (not shown). The active noise control (ANC) filter is commonly supplied with an electrical signal from a single (reference) microphone <NUM>, which picks up sound at a position which is adjustable by way of rod <NUM>. The rod <NUM> mounts the microphone <NUM> to the convex surface <NUM> of the shell <NUM> at a joint <NUM>. In order to allow the position of the microphone <NUM> to be adjustable, the rod <NUM> may be flexible (e.g., a gooseneck element) and/or the joint <NUM> may be articulated (e.g., a ball-and-socket j oint).

The ANC filter may, for example, be configured to provide feedforward type or hybrid type active noise control. Whatever characteristics the microphone <NUM> may have, a share of the sound emitted by a noise source may be picked-up by microphone <NUM> while another share may not be. However, both shares may reach the ear of a user (not shown) wearing the headphones so that the sound picked-up by the microphone <NUM> and, thus, the electrical signal corresponding to the picked-up sound does not or does not fully represent the sound arriving at the user's ear. How much the microphone signal corresponds to the sound perceived by the user depends on the position and the directivity of the microphone <NUM>. As a consequence, the noise reduction performance of the headphones is, inter alia, dependent on the position of the microphone <NUM> relative to the position of the noise source and the directivity of the microphone <NUM>. As the position of the microphone <NUM> and, if it has a higher directivity, also the overall directivity characteristic, are adjustable, a user wearing the headphones can, with appropriate adjustments, maximize the share of the sound picked-up by microphone <NUM>. Thus, the arrangement including the microphone <NUM>, the rod <NUM> and the joint <NUM> behaves like a kind of "mechanical" beamformer.

Instead of a single microphone with adjustable position and/or directivity characteristic, an earphone <NUM> with an array <NUM> of microphones <NUM> in connection with beamformer circuitry (not shown) may be employed, as shown in <FIG> which is a front view of the array of the microphones <NUM>, a lateral view of which is shown in <FIG>. As can be seen, the microphones are regularly distributed over a convex surface <NUM>, which means that the microphones <NUM> may be formed, built, arranged, or ordered according to some established rule, law, principle, or type. In For example, the microphones <NUM> may be arranged both equilaterally and equiangularly as a regular polygon (two-dimensional arrangement) or may have faces that are congruent regular polygons, with all the polyhedral angles being congruent, as a regular polyhedron (three-dimensional arrangement). For example, three microphones <NUM> may be used which can be arranged at the corners of an equilateral triangle. Other arrangements may have four microphones disposed in the corners of a square. A multiplicity of arrangements of regularly distributed three or four microphones or more may be combined to form more complex arrangements. For example, <FIG> show an arrangement of five microphones <NUM> regularly distributed over or in a convex surface <NUM> (e.g., a semi-sphere) with one microphone in the surface center.

Referring to <FIG> and <FIG>, beamformer circuitry applicable in connection with a microphone array <NUM> such as, e.g., the microphone array <NUM> shown in <FIG>, may include a beamformer block <NUM> or <NUM>, respectively. <FIG> is a signal flow chart illustrating the basic structure of beamformer block <NUM> which is connected to a plurality of Q microphones Mic1, Mic2,. MicQ that form microphone array <NUM>, and includes a matrixing unit <NUM> (also known as modal decomposer or eigenbeam former), and a modal beamformer <NUM>. The modal beamformer <NUM> comprises a steering unit <NUM>, a weighting unit <NUM>, and a summing element <NUM>. Each microphone Mic1, Mic2,. MicQ generates a time-varying analog or digital audio signal S<NUM>(θ<NUM>,φ<NUM>,ka), S<NUM>(θ<NUM>,φ<NUM>,ka). SQ(θQ,φQ,ka) corresponding to the sound incident at the location of that microphone. The matrixing unit <NUM> decomposes (according to Y+ = (YTY)-<NUM>YT) audio signals S<NUM>(θ<NUM>,φ<NUM>,ka), S<NUM>(θ<NUM>,φ<NUM>,ka). SQ(θQ,φQ,ka) generated by the array <NUM> to provide a set of spherical harmonics Y+<NUM><NUM>,<NUM>(θ,φ), Y+<NUM><NUM>,<NUM>(θ,φ),. Y+σm,n(θ,φ), also known as eigenbeams or modal outputs, wherein each spherical harmonic Y+<NUM><NUM>,<NUM>(θ,φ), Y+<NUM><NUM>,<NUM>(θ,φ),. Y+σm,n(θ,φ) corresponds to a different mode for the microphone array <NUM>. The spherical harmonics Y+<NUM><NUM>,<NUM>(θ,φ), Y+<NUM><NUM>,<NUM>(θ,φ),. Y+σm,n(θ,φ) are then processed by the modal beamformer <NUM> to provide an output signal <NUM> which is equal to Ψ(θDes,φDes). Instead of a single beampattern, modal beamformer <NUM> may simultaneously generate two or more different beampatterns, each of which can be independently steered into (almost) any direction in space. Alternatively, weighting unit <NUM> may be arranged upstream of steering unit <NUM> and not downstream as shown so that the non-steered eigenbeams are weighted (not shown).

As can be seen, it may not be easy to fulfill all given requirements in practice in order to utilize all theoretical concepts of modal beamformers, as it may not be easy to create headphones with hemispheric ear-cups, since they may have a bulky look which many may not consider to be a pleasing design. On the other hand it may also be sufficient to use microphones regularly spaced in a circle if a modal beamformer is only able to operate in one plane (two-dimensional). Unfortunately, this would be the vertical, and not, as desired, the horizontal plane, which makes this application possible, but, in fact, also questionable. A more practical solution to this problem emerges if the modal beamforming concept is upgraded by a Multiple-Input-Multiple-Output (MIMO) system, as depicted below in <FIG>. In this case it is possible to create a modal beamformer based on a body of arbitrary shape and on arbitrary positions of the microphones, as can be seen in <FIG>.

In the alternative beamformer block <NUM> shown in <FIG>, a multiple-input multiple-output system <NUM> is used instead of matrixing unit <NUM>. <FIG> illustrates schematically an alternative earphone <NUM> with an ear cup <NUM> that has an arbitrary shape and a non-regular, three-dimensional distribution of a multiplicity of utilized microphones <NUM>.

Referring to <FIG>, with the arrangements described above in connection with <FIG>, at least one beam (per earphone) can be formed, e.g., two beams <NUM> and <NUM> originating from two earphones <NUM> and <NUM>, and steered into any two-dimensional or three-dimensional direction where the primary noise source resides. All of this can be done with or even without a user <NUM> adjusting the beam(s) <NUM>, <NUM> to the direction of the noise source. Alternatively the beam(s) <NUM>, <NUM> of the earphones <NUM>, <NUM> may be steered to a desired target, e.g., a person <NUM> with whom the user <NUM> wants to communicate, herein referred to as awareness function. The combination of ANC with microphone beamforming for picking up the reference signal can be applied not only to feedforward ANC headphones, but can also be beneficially integrated into hybrid ANC systems such as the hybrid ANC system shown in <FIG> or into any other non-ANC headphone to realize a so-called awareness mode of operation.

When the earphone is in an ANC mode of operation , automatically steering one or more beams into any two-dimensional or three-dimensional direction where the primary noise source resides, i.e., steering without a user <NUM> adjusting the beam(s) <NUM>, <NUM> into the direction of the noise source, the direction where the primary noise source resides may be estimated by calculating multiple beams that point in different directions, and selecting therefrom the beam with the worst signal-to-noise ratio (SNR), which is indicative of a noise source in this direction. Alternatively or additionally, a single beam may scan all directions repeatedly while the respective SNR for each direction is determined. Again, the direction of the beam with the worst SNR is indicative of a noise source in this direction. In a combination of the two options described above, multiple beams scan in different (preferred) directions and the beam with the worst SNR then scans around its preferred direction within a predetermined directional section e.g., between two neighboring fixed beams pointing in different neighboring directions of the currently as the best fixed beam appointed (e.g., between +<NUM>° and -<NUM>°) around this preferred direction to allow for a fine tuning of the beam.

When the earphone is in an awareness mode of operation, the ANC mode of operation is deactivated and one or more beams are steered, as with the ANC mode of operation. However, not the beam with the worst SNR but the beam with the best SNR is selected. The beam with the best SNR represents the direction of a desired-sound source, e.g., a speaker.

Referring to <FIG>, in an exemplary far field microphone system applicable in the system shown in <FIG> in connection with the ANC mode of operation as well as the awareness mode of operation, sound from a desired sound source <NUM> travels through a room, where it is filtered with the corresponding room impulse responses (RIRs) <NUM> and may eventually be corrupted by noise, before the corresponding signals are picked up by M microphones <NUM> of the far field microphone system. The far field microphone system shown in <FIG> further includes an acoustic echo cancellation (AEC) block <NUM>, a subsequent fixed beamformer (FB) block <NUM>, a subsequent beam steering block <NUM>, a subsequent adaptive blocking filter (ABF) block <NUM>, a subsequent adaptive interference canceller block <NUM>, and a subsequent adaptive post filter block <NUM>. As can be seen from <FIG>, N source signals, filtered by the RIRs (hi, ···, hM), and eventually overlaid by noise, serve as an input to the AEC block <NUM>. The output signals of the fixed beamformer block <NUM> serve as an input bi (n), wherein i = <NUM>, <NUM>,. B, to the beam steering (BS) block <NUM>. Each signal from the fixed beamformer block <NUM> is taken from a different room direction and may have a different SNR level.

The BS block <NUM> delivers an output signal b(n) which represents the signal of the fixed beamformer block <NUM> pointing into room direction with the best/highest current SNR value, referred to as positive beam, and a signal bn(n), representing the current signal of the fixed beamformer block <NUM> with the least/lowest SNR value, referred to as negative beam. Based on these two signals b(n) and bn(n), the adaptive blocking filter (ABF) block <NUM> calculates, dependent on the mode of operation, an output signal e(n) which ideally solely contains the current noise signal, but no useful signal parts or vice versa.

When an ANC mode of operation is active (indicated by doted lines at the output of BS block <NUM> in <FIG>), the ABF filter block <NUM> may be configured to block, in an adaptive way, all signal parts other than useful signal parts still contained in the signal representing the positive beam b(n). The output signal e(n) of ABF filter block <NUM> enters, together with the optionally, by a delay (D) line <NUM> having a delay time γ, delayed signal representative of the negative beam bn(n-γ) the AIC block <NUM> including, from a structural perspective, also a subtractor block <NUM>. Based on these two input signals e(n) and bn(n-γ), the AIC block <NUM> including subtractor block <NUM> generates an output signal which acts, on the one hand, as an input signal to a successive adaptive post filter (PF) block <NUM> and, on the other hand, is fed back to the AIC block <NUM>, acting thereby as an error signal for the adaptation process which also employs AIC block <NUM>. The purpose of this adaptation process is to generate a signal which includes mainly noise signals and is ideally free of useful signals. In addition, the AIC block <NUM> also generates time-varying filter coefficients for the adaptive PF block <NUM> which is designed to remove further desired-signal components from the output signal of subtractor block <NUM> and thus from the negative beam bn(n) to generate a total output signal y(n) which is the pure noise signal and may be used as an input signal of a feedforward ANC system or a feedforward block of hybrid system such as, e.g., signal <NUM> in the hybrid ANC system depicted in <FIG>.

Similarly, when the awareness mode of operation is active (indicated by solid lines at the output of BS block <NUM> in <FIG>), the "adaptive blocking filter" may be configured to block, in an adaptive way, signal parts other than noise signal parts still contained in the signal representing the negative beam bn(n). The output signal e(n) of ABF filter block <NUM> enters, together with an optionally delayed signal representative of the positive beam b(n-γ) the AIC block <NUM> including, from a structural perspective, subtractor block <NUM>. Based on these two input signals e(n) and b(n-γ), the AIC block <NUM> generates an output signal which again, on the one hand, acts as an input signal to the successive adaptive post filter (PF) block <NUM> and, on the other hand, is fed back to the AIC block <NUM>, acting thereby as an error signal for the adaptation process, which also employs AIC block <NUM>. The purpose of this adaptation process is to generate a signal which includes mainly desired signals, ideally free of noise. In addition, the AIC block <NUM> also generates time-varying filter coefficients for the adaptive PF block <NUM> which is designed to remove further noise components from the output signal of subtractor block <NUM>, and thus from the positive beam b(n), to generate the total output signal y(n) which is the pure desired signal and may be reproduced by way of the loudspeaker(s) of the earphone(s).

Optionally, in a basically awareness mode of operation, one or more adaptively steerable spatial roots may be generated to hide one or more noise sources. In a further option, awareness and ANC modes can be active simultaneously to address multiple noise and/or desired-signal sources. In a still further option, multiple beams may be steered to at least one individual noise and/or desired-signal source and the signals therefrom may be summed up or otherwise combined to create a sum noise or sum desired-signal of the multiple beams.

Parts or all of the beamformer circuitry may be implemented as software and firmware executed by a processor or a programmable digital circuit. It is recognized that any beamformer circuit as disclosed herein may include any number of microprocessors, integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), or other suitable variants thereof) and software which co-act with one another to perform operation(s) disclosed herein. In addition, any beamformer circuitry as disclosed may utilize any one or more microprocessors to execute a computer-program that is embodied in a non-transitory computer readable medium that is programmed to perform any number of the functions as disclosed. Further, any controller as provided herein includes a housing and a various number of microprocessors, integrated circuits, and memory devices, (e.g., FLASH, random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EPROM), and/or electrically erasable programmable read only memory (EEPROM).

The description of embodiments has been presented for purposes of illustration and description. Suitable modifications and variations to the embodiments may be performed in light of the above description or may be acquired from practicing the methods. For example, unless otherwise noted, one or more of the described methods may be performed by a suitable device and/or combination of devices. The described methods and associated actions may also be performed in various orders in addition to the order described in this application, in parallel, and/or simultaneously. The described systems are exemplary in nature, and may include additional elements and/or omit elements.

As used in this application, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural of said elements or steps, unless such exclusion is stated. Furthermore, references to "one embodiment" or "one example" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. The terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements or a particular positional order on their objects.

Claim 1:
An active noise reducing earphone comprising:
a rigid cup shell (<NUM>, <NUM>) having an inner surface (<NUM>) and an outer surface (<NUM>), the inner surface (<NUM>) encompassing a cavity (<NUM>) with an opening (<NUM>);
a microphone arrangement (<NUM>) configured to pick up sound with at least one steerable beam directivity characteristic, and to provide a first electrical signal that represents the picked-up sound;
an active noise control filter (<NUM>) configured to provide, based on the first electrical signal, a second electrical signal; and
a speaker (<NUM>, <NUM>) disposed in the opening (<NUM>) of the cavity (<NUM>) and configured to generate sound from the second electrical signal;
wherein the active noise control filter (<NUM>) has a transfer characteristic that is configured so that noise that travels through the shell (<NUM>, <NUM>) from beyond the outer surface (<NUM>) to beyond the inner surface (<NUM>) is reduced by the sound generated by the speaker (<NUM>, <NUM>);
wherein the microphone arrangement (<NUM>) comprises:
an array (<NUM>) of multiple microphones (<NUM>), the multiple microphones (<NUM>) being distributed over the outer surface (<NUM>) of the shell (<NUM>, <NUM>), and
a beamformer block (<NUM>, <NUM>) electrically connected to the array (<NUM>) of multiple microphones (<NUM>) and configured to provide in connection with the array (<NUM>) of multiple microphones (<NUM>), a directivity characteristic of the array (<NUM>) of multiple microphones (<NUM>) that includes at least one beam; characterized in that:
the microphone arrangement (<NUM>) is configured to provide an awareness mode of operation in which one or more beams are steered in different directions and to evaluate a signal-to-noise ratio of each beam;
a direction in which one beam thereof having a highest signal-to-noise ratio is selected as a direction of a desired-sound source; and
the active noise control filter (<NUM>) is deactivated in the awareness mode while the one beam with the highest signal-to-noise ratio is selected as the direction of the desired-sound source.