Microphone device

Abstract

A microphone apparatus includes: an omnidirectional microphone providing a first microphone output signal; the one-way microphone is used for providing a second microphone output signal; a first filter unit providing a filtered first microphone output signal; and an adder providing a microphone arrangement output signal by adding the filtered first microphone output signal to the second microphone output signal or a filtered second microphone output signal provided by a second filter unit, the first filter unit removing an intermediate frequency range component from the first microphone output signal, the second filter unit removing an intermediate frequency range component from the second microphone output signal, the first filter unit filters the first microphone output signal such that the filtered first microphone output signal comprises only a low-frequency range component and a high-frequency range component, and the second filter unit removes the low-frequency range component and / or the high-frequency range component from the second microphone output signal such that the filtered second microphone output signal comprises only an intermediate-frequency range component, or the filtered second microphone output signal comprises an intermediate frequency range component and a low frequency range component or a high frequency range component.

Description

Technical Field

[0001] The present disclosure relates to a microphone device, and more particularly to a microphone device comprising a plurality of microphones. Background Art

[0002] For many applications, microphones need to provide a flat frequency response over a wide frequency range. For example, automatic speech recognition applications typically require a flat frequency response over a frequency range of at least 80 Hz to 16 kHz. Compared to omnidirectional microphones, unidirectional microphones provide a higher signal-to-noise ratio by having lower sensitivity in all directions except the main direction (e.g., the forward direction). For example, the directionality of a microphone arrangement can be achieved by arranging multiple microphone elements in a microphone array (beamforming array). Although unidirectional microphones have several advantages over omnidirectional microphones, unidirectional microphones typically do not have a flat frequency response over the entire frequency range and, therefore, cannot be easily used in applications that require both beamforming capabilities and a flat frequency response over a wide frequency range. Summary of the Invention

[0003] A microphone arrangement comprises: an omnidirectional microphone providing a first microphone output signal; a unidirectional microphone providing a second microphone output signal; a first filter unit configured to provide a filtered first microphone output signal; and an adder configured to provide a microphone arrangement output signal by adding the filtered first microphone output signal to the second microphone output signal or the filtered second microphone output signal provided by the second filter unit, wherein the first microphone output signal comprises a low-frequency range component, a mid-frequency range component, and a high-frequency range component, and the second microphone output signal comprises a low-frequency range component, a mid-frequency range component, and a high-frequency range component. The first filter unit is configured to remove the mid-frequency range component from the first microphone output signal, so that the filtered first microphone output signal only includes the low-frequency range component and the high-frequency range component of the first microphone output signal, and the second filter unit is configured to remove the low-frequency range component and / or the high-frequency range component from the second microphone output signal, so that the filtered second microphone output signal only includes the mid-frequency range component of the second microphone output signal, or the filtered second microphone output signal includes the mid-frequency range component and the low-frequency range component or the high-frequency range component of the second microphone output signal.

[0004] A method for operating a microphone arrangement comprises: providing a first microphone output signal by means of an omnidirectional microphone; providing a second microphone output signal by means of a unidirectional microphone; providing a filtered first microphone output signal by means of a first filter unit; and providing a microphone arrangement output signal by adding the filtered first microphone output signal to the second microphone output signal or the filtered second microphone output signal provided by means of the second filter unit, wherein the first microphone output signal comprises a low-frequency range component, a mid-frequency range component, and a high-frequency range component, and the second microphone output signal comprises a low-frequency range component, a mid-frequency range component, and a high-frequency range component. Providing a filtered first microphone output signal by means of the first filter unit comprises removing a mid-frequency range component from the first microphone output signal, so that the filtered first microphone output signal comprises only a low-frequency range component and a high-frequency range component of the first microphone output signal, and providing a filtered second microphone output signal by means of the second filter unit comprises removing a low-frequency range component and / or a high-frequency range component from the second microphone output signal, so that the filtered second microphone output signal comprises only a mid-frequency range component of the second microphone output signal, or the filtered second microphone output signal comprises a mid-frequency range component and a low-frequency range component or a high-frequency range component of the second microphone output signal.

[0005] Other systems, methods, features and advantages will be apparent to those skilled in the art upon review of the following detailed description and drawings, and it is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the following claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The arrangement may be better understood with reference to the following description and accompanying drawings. The components in the accompanying drawings are not necessarily drawn to scale, but rather are intended to illustrate the principles of the invention. In addition, in the accompanying drawings, the same reference numerals indicate corresponding parts throughout the different views.

[0007] Figure 1 The frequency response of a unidirectional microphone is schematically shown.

[0008] Figure 2 The frequency response of an omnidirectional microphone is schematically shown.

[0009] Figure 3 A microphone arrangement according to an embodiment of the present disclosure is schematically shown.

[0010] Figure 4 Schematically shows Figure 3 Frequency response of the microphone device.

[0011] Figure 5A method for operating a microphone arrangement according to an example is schematically illustrated in a flow chart. DETAILED DESCRIPTION

[0012] As required, detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various alternative forms. The drawings are not necessarily drawn to scale; some features may be exaggerated or minimized to illustrate details of particular components. Therefore, the specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0013] It should be understood that directional terms (e.g., "upper," "lower," "inner," "outer," "top," "bottom," etc.) that may be mentioned herein refer only to the orientation of the various components of the device as shown in the accompanying drawings. These terms are provided for context and understanding of the disclosed embodiments.

[0014] It is often desirable for a microphone to have a flat frequency response over a wide frequency range, for example, from 20 Hz to 16 kHz or even up to 20 kHz. The frequency response of a microphone or microphone arrangement is generally defined as a quantitative measure of the amplitude of the output signal as a function of the input frequency. In conventional unidirectional microphones or microphone arrangements, the frequency response can vary by 50 dB or even more over the entire frequency range. Figure 1 The frequency response of a conventional unidirectional microphone is schematically shown. In this example, the frequency response comprises a variation of approximately 40 dB across the frequency range.

[0015] If the variation across the frequency range is less than 10 dB or even less than 5 dB, the frequency response can be considered flat. For example, automatic speech recognition applications often require a flat frequency response. Figure 1 In the example of , the frequency response can be considered flat only within a limited frequency range. Figure 1 In the example shown, this limited frequency range is between approximately 300 Hz and 7 kHz. Figure 1 The useful frequency range is designated as the useful frequency range. The useful frequency range may vary for different unidirectional microphones. The lower limit of the useful frequency range may be, for example, 300 Hz, 400 Hz, or 800 Hz. The upper limit of the useful frequency range may be, for example, 4 kHz, 8 kHz, or 10 kHz. However, any other lower or upper limit range is generally possible, depending on the specific unidirectional microphone used.

[0016] Unidirectional (directional) microphones offer a higher signal-to-noise ratio by having lower sensitivity in all directions except the primary (i.e., forward) direction. Therefore, for many applications, unidirectional microphones are superior to omnidirectional microphones. However, due to physical limitations, unidirectional microphones are typically limited in terms of high and low frequencies. That is, without additional gain in these high and low frequency ranges, unidirectional microphones typically cannot meet the requirements of, for example, advanced speech recognition algorithms. However, additional gain can negatively impact the signal-to-noise ratio by significantly increasing the noise level at both low and high frequencies.

[0017] In order to maintain the advantages of unidirectional microphones (e.g., high signal-to-noise ratio) while providing a flat frequency response over a desired wide frequency range (e.g., between about 40 Hz / 80 Hz and 16 kHz or even up to 20 kHz), the microphone system according to an embodiment of the present disclosure includes an omnidirectional microphone in addition to the unidirectional microphone. Figure 2 As shown schematically, the frequency response of an omnidirectional microphone is generally considered to be flat at low and high frequencies. That is, for example, the frequency response of an omnidirectional microphone is considered to be flat at frequencies below about 300 Hz and above about 7 kHz. The variation in the frequency response of an omnidirectional microphone at high frequencies is generally significantly less than the variation in the frequency response of a unidirectional microphone over the same frequency range. Figure 1 and Figure 2 In the example shown, for example, the variation in the frequency response of a unidirectional microphone at frequencies above 7 kHz is about 20 dB, whereas the variation in the frequency response of an omnidirectional microphone at frequencies above 7 kHz is about 10 dB or even less.

[0018] In the following, an example of a microphone arrangement with a flat ultra-wideband frequency response is described. To achieve this, the system adds the low-frequency range components and the high-frequency range components of an omnidirectional microphone signal and a unidirectional microphone signal, the unidirectional microphone signal comprising only the mid-frequency range components of the unidirectional microphone signal, or the mid-frequency range components and the low-frequency range components and / or the high-frequency range components of the unidirectional microphone signal. Figure 3, schematically shows a microphone arrangement according to an embodiment of the present disclosure. The microphone arrangement comprises: an omnidirectional microphone 202 providing a first microphone output signal s1[n]; a unidirectional microphone 204 providing a second microphone output signal s2[n]; a first filter unit 402 configured to provide a filtered first microphone output signal s1'[n]; and an adder 500 configured to provide a microphone arrangement output signal sout[n] by adding the filtered first microphone output signal s1'[n] to the second microphone output signal s2[n] or the filtered second microphone output signal s2'[n] provided by the (optional) second filter unit 404. The first microphone output signal s1[n] comprises a low-frequency range component, a mid-frequency range component, and a high-frequency range component, and the second microphone output signal s2[n] comprises a low-frequency range component, a mid-frequency range component, and a high-frequency range component. The first filter unit 402 is configured to remove the mid-frequency range component from the first microphone output signal s1[n], so that the filtered first microphone output signal s1'[n] only includes the low-frequency range component and the high-frequency range component of the first microphone output signal s1[n]. If the filtered first microphone output signal s1'[n] is added to the second microphone output signal s2[n], the second filter unit 404 ( Figure 3 ), or the second filter unit 404 may be completely omitted. In a microphone arrangement comprising the second filter unit 404, the second filter unit 404 is configured to remove the low frequency range component and / or the high frequency range component from the second microphone output signal s2[n], such that the filtered second microphone output signal s2'[n] comprises only the mid-frequency range component of the second microphone output signal s2[n], or the filtered second microphone output signal s2'[n] comprises the mid-frequency range component and the low frequency range component and / or the high frequency range component of the second microphone output signal s2[n].

[0019] That is, providing the microphone arrangement output signal sout[n] by adding the filtered first microphone output signal s1′[n] to the second microphone output signal s2[n] and the filtered second microphone output signal s2′[n] comprises combining the low-frequency range component and the high-frequency range component of the first microphone output signal s1[n] (of the omnidirectional microphone 202) with only the mid-frequency range component of the second microphone output signal s2[n] or with the mid-frequency range component and the low-frequency range component and / or the high-frequency range component of the second microphone output signal s2[n] (of the unidirectional microphone 204). Therefore, the resulting microphone arrangement output signal sout[n] can be regarded as a mixed signal comprising the low-frequency range component and the high-frequency range component of the first microphone output signal s1[n] and the mid-frequency range component of the second microphone output signal s2[n], and optionally also the low-frequency range component and / or the high-frequency range component of the second microphone output signal s2[n]. In all cases, the resulting frequency response of the microphone arrangement output signal sout[n] is flat. If the low-frequency range component and the high-frequency range component of the first microphone output signal s1[n] are added to the unfiltered second microphone output signal s2[n], a frequency response that is flatter than the frequency response of a unidirectional microphone can be achieved. However, if the low-frequency range component and the high-frequency range component of the first microphone output signal s1[n] are added only to the mid-frequency range component of the second microphone output signal s2[n], a particularly flat frequency response can be achieved, as shown in FIG. Figure 4 As shown schematically, it can be seen that in this case, the frequency response remains between about -4 dB and +8 dB for all frequencies between 40 Hz and about 20 kHz. The frequency response of a conventional unidirectional microphone array 20 typically has a low frequency sensitivity drop and a high frequency sensitivity drop, as described above with respect to Figure 1 As described above. With the exemplary microphone arrangement described herein, these low-frequency and high-frequency sensitivity reductions can be offset, thereby producing a flat frequency response across the entire frequency range. It is generally possible to not filter the second microphone output signal s2[n] at all, or to remove only the low-frequency range component or the high-frequency range component, but this may be limited to certain special cases, as it may not always produce a microphone arrangement output signal sout[n] that meets the requirement of a flat frequency response across a wide frequency range.

[0020] An omnidirectional microphone typically picks up sound with equal gain from all sides or directions. A unidirectional microphone 204 picks up sound with high gain only from a specific direction. Omnidirectional microphone 202 and unidirectional microphone 204 pick up sound from a sound source 10. Sound source 10 can be, for example, a person or a speaker. However, any other sound source is also possible.

[0021] For example, the system can filter the first microphone output signal s1[n] and the second microphone output signal s2[n] using filters (such as a low-pass filter and a high-pass filter for the low-frequency and high-frequency components of the omnidirectional microphone 202, and an intermediate frequency bandpass filter, a high-pass filter, or a low-pass filter for the unidirectional microphone 204). That is, the first filter unit 402 may include a low-pass filter and a high-pass filter, and the second filter unit 404 may include a bandpass filter, a high-pass filter, or a low-pass filter. This offsets the low-frequency sensitivity drop and the high-frequency sensitivity drop in the frequency response of the unidirectional microphone 204.

[0022] The omnidirectional microphone 202 and the unidirectional microphone 204 may be arranged as close as possible. That is, the distance D between the omnidirectional microphone 202 and the unidirectional microphone 204 may be less than 5 cm or even less than 2 cm. Figure 3 As indicated by the dashed lines in FIG, omnidirectional microphone 202 and unidirectional microphone 204 can be arranged in the same housing 30. In this way, the microphone arrangement can be made very compact and small, and does not require much space. Filter units 402, 404 can be integrated into the same housing 30, or can be arranged outside of housing 30. The same applies to adder 500, which can be arranged inside or outside of housing 30.

[0023] The omnidirectional microphone 202 and the unidirectional microphone can generally be implemented in any suitable manner. For example, the omnidirectional microphone 202 can include a micro-electromechanical system (MEMS) microphone element or an electret capacitor (ECM) microphone element. The same applies to the unidirectional microphone 204, which can include a micro-electromechanical system (MEMS) microphone element or an electret capacitor (ECM) microphone element. Different types of microphones can generally be combined in any manner. For example, both the omnidirectional microphone 202 and the unidirectional microphone 204 can include micro-electromechanical system (MEMS) microphone elements. According to another example, both the omnidirectional microphone 202 and the unidirectional microphone 204 can include electret capacitor (ECM) microphone elements. According to an even further example, the omnidirectional microphone 202 can include an electret capacitor (ECM) microphone element, while the unidirectional microphone 203 can include a micro-electromechanical system (MEMS) microphone element. However, according to a further example, if the omnidirectional microphone 202 includes a micro-electromechanical system (MEMS) type microphone element and the unidirectional microphone 204 includes an electret capacitor (ECM) type microphone element, the microphone arrangement can be implemented in a very compact and space-saving manner. This is because a MEMS type omnidirectional microphone can generally be integrated with an ECM type unidirectional microphone in a very compact and space-saving manner.

[0024] The omnidirectional microphone 202 may include a single (only one / no more than one) microphone element. The unidirectional microphone 204 may also include only a single (only one / no more than one) microphone element. However, if there is sufficient space, the unidirectional microphone 204 may alternatively include an array of at least two microphone elements. For example, each of the at least two microphone elements may be an omnidirectional microphone element. The directional output signal of such a microphone array may be obtained using suitable signal processing techniques, which are generally known and therefore not described in further detail herein.

[0025] For the first microphone output signal s1[n] and the second microphone output signal s2[n], the following may apply: the low-frequency component includes frequencies below 300 Hz, below 400 Hz or below 800 Hz, the mid-frequency component includes frequencies between 300 Hz, 400 Hz or 800 Hz and 4 kHz, 8 kHz or 10 kHz, and the high-frequency component includes frequencies greater than 4 kHz, greater than 8 kHz or greater than 10 kHz.

[0026] In summary, the exemplary microphone arrangement provides ultra-wideband frequency characteristics without sacrificing sound-to-noise ratio by adding noise in the low and high frequency bands. The frequency responses exemplarily shown in the figures and described herein are merely examples. In general, how the frequency response varies across the frequency range depends on several factors and may vary from microphone to microphone.

[0027] Now refer to Figure 5, schematically illustrates a method according to an embodiment of the present disclosure. The method comprises: providing a first microphone output signal s1[n] by means of an omnidirectional microphone 202 (step 501); providing a second microphone output signal s2[n] by means of a unidirectional microphone 204 (step 502); providing a filtered first microphone output signal s1'[n] by means of a first filter unit 402 (step 503); and providing a microphone arrangement output signal sout[n] by adding the filtered first microphone output signal s1'[n] to the second microphone output signal or the filtered second microphone output signal s2'[n] provided by means of the second filter unit (step 504). The first microphone output signal s1[n] comprises a low frequency range component, a mid-frequency range component, and a high frequency range component, and the second microphone output signal s2[n] comprises a low frequency range component, a mid-frequency range component, and a high frequency range component. Providing a filtered first microphone output signal s1'[n] by means of the first filter unit 402 includes removing the mid-frequency range component from the first microphone output signal s1[n], so that the filtered first microphone output signal s1'[n] only includes the low-frequency range component and the high-frequency range component of the first microphone output signal s1[n], and providing a filtered second microphone output signal s2'[n] by means of the second filter unit 404 includes removing the low-frequency range component and / or the high-frequency range component from the second microphone output signal s2[n], so that the filtered second microphone output signal s2'[n] only includes the mid-frequency range component of the second microphone output signal s2[n], or the filtered second microphone output signal s2'[n] includes the mid-frequency range component and the low-frequency range component or the high-frequency range component of the second microphone output signal s2[n].

[0028] Providing a filtered first microphone output signal s1'[n] by means of the first filter unit 402 may comprise removing a mid-frequency range component from the first microphone output signal s1[n] by means of a low-pass filter and a high-pass filter, and providing a filtered second microphone output signal s2'[n] by means of the second filter unit 404 may comprise removing a low-frequency range component and a high-frequency range component from the second microphone output signal s2[n] by means of a band-pass filter, or removing the low-frequency range component from the second microphone output signal s2[n] by means of a high-pass filter, or removing the high-frequency range component from the second microphone output signal by means of a low-pass filter.

[0029] Providing the microphone device output signal sout[n] by adding the filtered first microphone output signal s1'[n] to the second microphone output signal s2[n] or the filtered second microphone output signal s2'[n] may include combining a low frequency range component and a high frequency range component of the first microphone output signal s1[n] with a mid frequency range component of the second microphone output signal s2[n] or with a mid frequency range component and at least one of a low frequency range component and a high frequency range component of the second microphone output signal s2[n].

[0030] For the first microphone output signal s1[n] and the second microphone output signal s2[n], the following may apply: the low-frequency component includes frequencies below 300 Hz, below 400 Hz or below 800 Hz, the mid-frequency component includes frequencies between 300 Hz, 400 Hz or 800 Hz and 4 kHz, 8 kHz or 10 kHz, and the high-frequency component includes frequencies greater than 4 kHz, greater than 8 kHz or greater than 10 kHz.

[0031] The description of the embodiments has been presented for illustration and description purposes. Suitable modifications and variations of the embodiments may be performed according to the above description or may be obtained by practical methods. The arrangements are exemplary in nature and may include additional elements and / or omit elements. As used in this application, elements listed in the singular and preceded by the wording "one" or "an" should not be understood to exclude a plurality of said elements unless such exclusion is indicated. In addition, reference to "one embodiment" or "an example" of the present disclosure is not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the enumerated features. The terms "first," "second," and "third," etc. are used only as labels and are not intended to impose numerical requirements or a specific positional order on their objects. The described systems are exemplary in nature and may include additional elements and / or omit elements. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations disclosed and other features, functions, and / or properties. The following claims specifically disclose subject matter that is considered novel and non-obvious from the above description.

Claims

1. A microphone device comprising: an omnidirectional microphone (202) providing a first microphone output signal (s1[n]); a unidirectional microphone (204) providing a second microphone output signal (s2[n]); a first filter unit (402) configured to provide a filtered first microphone output signal (s1'[n]); as well as an adder (500) configured to provide a microphone arrangement output signal (sout[n]) by adding the filtered first microphone output signal (s1'[n]) and the second microphone output signal (s2[n]) or the filtered second microphone output signal (s2'[n]) provided by the second filter unit (404), wherein the first microphone output signal (s1[n]) comprises a low-frequency range component, a mid-frequency range component and a high-frequency range component, and the second microphone output signal (s2[n]) comprises a low-frequency range component, a mid-frequency range component and a high-frequency range component, The first filter unit (402) is configured to remove the mid-frequency range component from the first microphone output signal (s1[n]) so that the filtered first microphone output signal (s1'[n]) only includes the low-frequency range component and the high-frequency range component of the first microphone output signal (s1[n]), and The second filter unit (404) is configured to remove the low-frequency range component and / or the high-frequency range component from the second microphone output signal (s2[n]) so that the filtered second microphone output signal (s2'[n]) only includes the mid-frequency range component of the second microphone output signal (s2[n]), or the filtered second microphone output signal (s2'[n]) includes the mid-frequency range component and the low-frequency range component or the high-frequency range component of the second microphone output signal (s2[n]).

2. The microphone device of claim 1, wherein the first filter unit (402) comprises a low-pass filter and a high-pass filter, and the second filter unit (404) comprises one of a band-pass filter, a low-pass filter, and a high-pass filter.

3. The microphone arrangement according to claim 1 or 2, wherein a distance (D) between the omnidirectional microphone (202) and the unidirectional microphone (204) is less than 5 cm or less than 2 cm.

4. The microphone arrangement according to any one of claims 1 to 3, wherein the omnidirectional microphone (202) and the unidirectional microphone (204) are arranged in a same housing (30).

5. The microphone arrangement according to any one of claims 1 to 4, wherein the omnidirectional microphone (202) comprises a Micro Electro Mechanical System (MEMS) type microphone element, and the unidirectional microphone (204) comprises an Electret Capacitor (ECM) type microphone element.

6. The microphone arrangement of any one of claims 1 to 5, wherein the unidirectional microphone (204) comprises an array of at least two microphone elements.

7. The microphone arrangement of claim 6, wherein each of the at least two microphone elements is an omnidirectional microphone element.

8. Microphone arrangement according to any of the preceding claims, wherein for the first microphone output signal (s1[n]) and the second microphone output signal (s2[n]) the following applies: The low-frequency components include frequencies below 300 Hz, below 400 Hz, or below 800 Hz, The intermediate frequency components include frequencies between 300 Hz, 400 Hz or 800 Hz and 4 kHz, 8 kHz or 10 kHz, and The high frequency component includes a frequency greater than 4 kHz, greater than 8 kHz, or greater than 10 kHz.

9. A method for operating a microphone arrangement, the method comprising: Providing a first microphone output signal (s1[n]) by means of an omnidirectional microphone (202); providing a second microphone output signal (s2[n]) by means of a unidirectional microphone (204); providing a filtered first microphone output signal (s1'[n]) by means of a first filter unit (402); as well as A microphone arrangement output signal (sout[n]) is provided by adding the filtered first microphone output signal (s1'[n]) and the second microphone output signal (s2[n]) or the filtered second microphone output signal (s2'[n]) provided by means of a second filter unit (404), wherein the first microphone output signal (s1[n]) comprises a low-frequency range component, a mid-frequency range component and a high-frequency range component, and the second microphone output signal (s2[n]) comprises a low-frequency range component, a mid-frequency range component and a high-frequency range component, providing a filtered first microphone output signal (s1'[n]) by means of the first filter unit (402) comprises removing the intermediate frequency range component from the first microphone output signal (s1[n]), such that the filtered first microphone output signal (s1'[n]) comprises only the low frequency range component and the high frequency range component of the first microphone output signal (s1[n]), and Providing a filtered second microphone output signal (s2'[n]) by means of the second filter unit (404) includes removing the low frequency range component and / or the high frequency range component from the second microphone output signal (s2[n]), so that the filtered second microphone output signal (s2'[n]) only includes the mid-frequency range component of the second microphone output signal (s2[n]), or the filtered second microphone output signal (s2'[n]) includes the mid-frequency range component and the low frequency range component or the high frequency range component of the second microphone output signal (s2[n]).

10. The method of claim 9, wherein Providing a filtered first microphone output signal (s1'[n]) by means of the first filter unit (402) comprises removing the intermediate frequency range component from the first microphone output signal (s1[n]) by means of a low-pass filter and a high-pass filter, and Providing a filtered second microphone output signal (s2'[n]) by means of the second filter unit (404) comprises removing the low frequency range component and the high frequency range component from the second microphone output signal (s2[n]) by means of a bandpass filter, or removing the low frequency range component from the second microphone output signal (s2[n]) by means of a high pass filter, or removing the high frequency range component from the second microphone output signal (s2[n]) by means of a low pass filter.

11. A method as claimed in claim 9 or 10, wherein providing a microphone device output signal (sout[n]) by adding the filtered first microphone output signal (s1'[n]) to the second microphone output signal (s2[n]) or the filtered second microphone output signal (s2'[n]) comprises combining the low frequency range component and the high frequency range component of the first microphone output signal (s1[n]) with the mid-frequency range component of the second microphone output signal (s2[n]) or combining with the mid-frequency range component and at least one of the low frequency range component and the high frequency range component of the second microphone output signal (s2[n]).

12. The method according to any one of claims 9 to 11, wherein for the first microphone output signal (s1[n]) and the second microphone output signal (s2[n]), the following applies: The low-frequency components include frequencies below 300 Hz, below 400 Hz, or below 800 Hz, The intermediate frequency components include frequencies between 300 Hz, 400 Hz or 800 Hz and 4 kHz, 8 kHz or 10 kHz, and The high frequency component includes a frequency greater than 4 kHz, greater than 8 kHz, or greater than 10 kHz.

Images