WO2023089380A1

WO2023089380A1 - A noise reduction system for headphones and speech microphones

Info

Publication number: WO2023089380A1
Application number: PCT/IB2022/050419
Authority: WO
Inventors: Rajesh Ramanathan
Original assignee: Rajesh Ramanathan
Priority date: 2021-11-19
Filing date: 2022-01-19
Publication date: 2023-05-25

Abstract

A noise reduction system for headphones and microphones is disclosed. The system includes an active noise reduction module. The active noise reduction module includes an analog signal processor communicatively coupled to speakers, microphones,and configured to eliminate active noise for the headphones; a digital signal processor communicatively coupled to at least one of the speakers, the microphones, or a combination thereof, and configured to eliminate active noise for the headphones and to enhance speech quality of a user captured via the one or more microphones. The system also includes a passive noise reduction module operatively coupled to the active noise reduction module. The passive noise reduction module includes a plurality of acoustic rubber pads operatively coupled across a pair of headphone cups, composed of at least one of glass filled synthetic polymer, comprising a foam material. The plurality of acoustic rubber pads is configured to absorb noise from surrounding environment.

Description

A NOISE REDUCTION SYSTEM FOR HEADPHONES AND SPEECH MICROPHONES

EARLIEST PRIORITY DATE:

This Application claims priority from a Complete patent application filed in India having Patent Application No. 202141053357, filed on November 19, 2021 and titled “A NOISE REDUCTION SYSTEM FOR HEADPHONES AND SPEECH MICROPHONES”.

FIELD OF INVENTION

Embodiments of a present invention relate to noise reduction in headphones and speech microphones, and more particularly, to an active and passive noise reduction system for the headphones and speech microphones.

BACKGROUND

Noise reduction is the process of removing noise from an audio signal. The signal may be an input signal or an output signal. Such a noise reduction techniques are widely applied on electronic communication appliances such as headphones and microphones. In a conventional headphones which includes an inbuilt microphone too, a noise reduction system is used to reduce the noise in the headphones and the microphone. Such noise reduction system provides noise reduction for continuous or for impact sounds and upto a certain decibel of noise level only. Also, the noise reduction is restricted to mostly speakers and not to the microphones. Due to such limitations, under extreme conditions of Noise/Sounds above 1 lOdb, which is not fully realized in such conventional systems.

In addition, the material used for ear cups of the headphones varies from one manufacturer to another, because of which the noise reduction reduces after certain frequency at a certain decibel. Also, due to the varying design structure of the ear cups, may cause a reason for reduced noise reduction. Especially, when the headphones is worn by a user, sealing of user’s ears may not happen completely at the area behind ear lobes. In addition, the material used for filling an inside of the head cups which can add on to the noise reduction beyond certin frequency of noise. In addition, placement of multiple speakers and microphones, if not accurate for the constructed design, the noise reduction is to be compromised on.

Hence, there is a need for an improved noise reduction system for the headphones and microphones in order to address the aforementioned issues.

BRIEF DESCRIPTION

In accordance with one embodiment of the disclosure, a noise reduction system for headphones and speech microphone is disclosed. The system includes an active noise reduction module. The active noise reduction module includes an analog signal processor communicatively coupled to at least one of one or more speakers, one or more microphones, or a combination thereof. The analog signal processor is configured to eliminate active noise for the headphones and speech microphone mounted on a flexible boom arm. The active noise reduction module also includes a digital signal processor communicatively coupled to at least one of a speaker, a microphone, or a combination thereof. The digital signal processor is configured to eliminate active noise for the headphones and to enhance speech quality of a user captured via the one or more microphones. The system also includes a passive noise reduction module operatively coupled to the active noise reduction module. The passive noise reduction module includes a plurality of acoustic rubber pads operatively coupled across a pair of headphone cups comprising a foam material. The plurality of acoustic rubber pads is configured to absorb noise from surrounding environment.

To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures. BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:

FIG. 1 is a block diagram representation of a noise reduction system for headphones in accordance with an embodiment of the present disclosure

FIG. 2 is a schematic reprasentation of an embodiment of the headphones with the noise reduction system of FIG. 1 in accordance with an embodiment of the present disclosure; and

FIG. 3 is a schematic representation of the active noise reduction module, in accordance with an embodiment of the present disclosure.

Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.

DETAILED DESCRIPTION

For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or sub-systems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.

In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.

Embodiments of the present disclosure relate to a noise reduction system for headphones and microphones. As used herein, the term ‘headphones’ is defined as a pair of small loudspeaker drivers worn on or around the head over a user's ears. In one embdiemnt, the headphones may be integrated with a boom microphone. As used herein, the term, ‘headphones with the boom microphone’ is defined as the type of headphones with a speech microphones mounted on a flexible boom arm.

Turning to FIGs 1, 2 and 3, FIG. 1 is a block diagram representation of a noise reduction system (10) for headphones (20) and a microphone (60) in accordance with an embodiment of the present disclosure. FIG. 2 is a schematic reprasentation of an embodiment of the headphones (20) and the microphone (60) with the noise reduction system (10) of FIG. 1 in accordance with an embodiment of the present disclosure. FIG. 3 is a schematic block diagram representation of the active noise reduction module (30), in accordance with an embodiment of the present disclosure. The system (10) includes an active noise reduction module (30). The active noise reduction module (30) includes an analog signal processor (40) communicatively coupled to at least one of one or more speakers (50), one or more microphones (60), or a combination thereof. The analog signal processor (40) is configured to eliminate active noise from an environment, for the headphones (20). As used herein, the term ‘analog signal processing’ is defined as a kind of electronic circuit used to perform analog signal processing. Analog signal processing is defined as a type of signal processing technique conducted on continuous analog signals via analog means. In one embodiment, the one or more microphones (60) may include a speech microphone which may be mounted on the flexible boom arm.

The active noise reduction module (30) also includes a digital signal processor (70) communicatively coupled to at least one of the one or more speakers (50), the one or more microphones (60), or a combination thereof. The digital signal processor (70) is configured to eliminate active noise for the one or more microphones (60) mounted on the flexible boom arm (25) of the headphones (20). In one embodiment, the active noise may be eliminated using an active noise cancellation technique. As used herein, the term ‘ active noise cancellation technique’ is defined as a kind of a technique in which an anti-noise signal of a pre-defined frequency is generated to cancel out the noise from the signal. This may be achieved using the active noise reduction module in order to generate a refined quality of audio signal which may be transmitted with a very specific adaptive time lag, to counter the noise sound waves as it changes constantly for different environments to the one or more speakers (50) of the headphones (20). The “adaptive time lag” is defined as the varying time difference between the noise signal and anti-noise signal from reaching eardrum of the user from the ear cup (100). This varying time lag is generated collectively by the active noise reduction module (30), the one or more speakers (50), one or more microphones (60) and an acoustic shaft (110).

In one specific embodiment, the one or more speakers (50) may be two in each of a corresponding pair of headphone cups (100) which may be housed in a corresponding enclosure and the one or more microphones (60).

The digital signal processor (70) is also configured to enhance speech quality of a user captured via the one or more microphones (60). In one embodiment, the one or more microphones (60) may include at least two microphones, tactically and acoustically placed in a small enclosure mounted on the flexible boom arm (25). In one specific embodiment, a plurality of microphones may be coupled together in a pre-defined arrangement which may be referred as acoustic arrangement, which may be configured to eliminate noise from the environment.

Furthermore, the system (10) includes a passive noise reduction module (80) operatively coupled to the active noise reduction module (40). The passive noise reduction module (80) includes a plurality of acoustic rubber pads (90) operatively coupled across the pair of headphone cups (100). In one embodiment, each of the plurality of acoustic rubber pads (90) corresponds to a shape of the pair of headphone cups (100). The pair of headphone cups includes a foam material. Further, the plurality of acoustic rubber pads (90) is configured to absorb and behave as a barrier to noise from the surrounding environment. The pair of headphone cups (100) is composed of at least one of glass filled synthetic polymer. The foam material corresponds to Neoprene rubber with viscous elastic foam material filling. In one embodiment, the system (10) may include the acoustic shaft (110) which may be housed within the corresponding pair of headphone cups (100). The acoustic shaft (110) may be configured for aligning the directivity of the required noise sound waves towards the one or more microphones (60). In one embodiment, the system (10) may further include a metal + foam + fabric mesh (120) which may be housed within the corresponding pair of headphone cups (100). The metal + foam + fabric mesh is used for acoustically filtering out certain enhanced noise frequencies, thereby reducing the amount of noise heard by the ear of the user.

In one specific embodiment, an inner surface of the pair of headphone cups (100) may be composed of a combination of porous acoustic foam and poly wool (130). In one exemplary embodiment, the system (10) may further include an acoustic material housed within each of the pair of headphone cups (100) in a pre-defined format. In such embodiment, the predefined format may correspond to a shape facilitating to mount all components inside the headphone cups (100). Moreover, the pair of headphone cups (100) are operatively coupled via an adjustable head strap, which is ruggedized for better comfort. In one exemplary embodiment, the system (10) includes a rugged cable for connecting the headphones (20) to a computing device for functioning of the headphones (20). The rugged cable includes an electronic unit (140) which houses the active noise reduction module (30) and a multi-function PTT (140) which may be customizable.

In operation, as the rugged cable of the headphones (20) is connected to the computing device or media source. For example: walkie-talkie, portable radio set, wired and wireless intercom, mobile phone, any device outputting audio signals, or the like depending on the media being played on the computing device, the one or more speakers (50), the one or more microphones (60) gets activated upon receiving an activation signal by a corresponding processor or a speech signal from the corresponding processor upon identifying the speech of the user. Upon activating the electronic components of the headphones (20) and the one or more microphones (60), the active noise reduction module (30) and the passive noise reduction module (80) gets initiated and the process of active noise reduction and passive noise reduction is achieved.

Furthermore, turning to FIG. 3, the analog signal processor (40) includes an inverter and time lag generator (160) connected to each of the right and left microphones (60) independently. The output from each of the microphones is transmitted to the corresponding invertor (160). Consequently, the output from each of the invertor (160) is transmitted to a corresponding equalizer (170). Further, output from equalizers of the left microphones are mixed together using a first mixer (180a), and the output from the equalizers of the right microphones are mixed using a second mixer (180b). Output of both the first and the second microphones are transmitted to an amplifier (190) for further amplification which acts as an input for the corresponding speakers (50). In addition, an input from a computing device or media source or a transmitter (200) is sent as an input for the corresponding speakers (50).

Further, digital signal processer (70) is connected to a computing device or a media receiver (210). The DSP (70) is a part of the active noise reduction module (30). The DSP (70) includes an AD/DA converter (220,230), whose output if transmitted to the inverter (160), totaling 12 equalizers (170) and again an inverter (160) and further, the output from the inverter (160) is transmitted to a third mixer (180c).

Various embodiments of the present disclosure enable the noise reduction system for the headphones to provide acoustic barrier property for a wide range of frequencies at a low decibel as well as high decibel level. The material also reduces the penetration of certain band of frequencies. Further, the Neoprene rubber with viscos elastic foam filling which helps the headphone cup pads to form itself on bone and facial muscle structure around the ear of the user, thereby giving maximum sealing to external noise. In addition, the Combination of porous acoustic foam and poly wool reduces the penetration of certain band of frequencies.

Moreover, the analog electronics reduces frequencies at a certain band, digital signal processing with a proprietary algorithm reduces frequencies at a certain band. The combination of both gives rise to noise reduction at a wide range of frequencies at high decibel levels, especially at low frequencies. These features enable the noise reduction in both speakers and the microphones of the headphones to almost 90% accuracy by also reducing the wide range of frequencies at high decibel levels, thereby making the system more reliable and highly efficient.

While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.

The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, order of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.

Claims

AIM:

1. A noise reduction system (10) for at least one of one or more headphones (20), one or more speakers (50), one or more microphones (60), or a combination thereof, wherein the system comprises: an active noise reduction module (30) comprising: an analog signal processor (40) communicatively coupled to at least one of one or more speakers (50), one or more microphones (60), or a combination thereof, wherein the analog signal processor (40) is configured to eliminate active noise from an environment, for the headphones (20) and speech microphone (60) mounted on a flexible boom arm (25); and a digital signal processor (70) communicatively coupled to at least one of the one or more speakers (50), the one or more microphones (60), or a combination thereof, wherein the digital signal processor (70) is configured to: eliminate active noise for the headphones (20); and enhance speech quality of a user captured via the one or more microphones (60); and a passive noise reduction module (80) operatively coupled to the active noise reduction module (40), wherein the passive noise reduction module (80) comprises: a plurality of acoustic rubber pads (90) operatively coupled across a pair of headphone cups (100) comprising a foam material, wherein the plurality of acoustic rubber pads (90) is configured to absorb noise from surrounding environment, wherein the pair of headphone cups (100) is composed of at least one of glass filled synthetic polymer, wherein the foam material corresponds to Neoprene rubber with viscous elastic foam material.

2. The noise reduction system (10) as claimed in claim 1, wherein each of the plurality of acoustic rubber pads (90) corresponds to a shape of the pair of headphone cups (100).

3. The noise reduction system (10) as claimed in claim 1, comprising an acoustic material housed within each of the pair of headphone cups (100) in a pre-defined format.

4. The noise reduction system (10) as claimed in claim 1, wherein the one or more microphones (60) comprises one of an internal microphone, an external microphone, or a combination thereof.

5. The noise reduction system (10) as claimed in claim 1, wherein the one or more speakers (50) comprises one of an internal speakers, an external speaker, or a combination thereof.

6. The noise reduction system (10) as claimed in claim 1, wherein an inner surface of the pair of headphone cups (100) is composed of a combination of porous acoustic foam and poly wool.