Method for performing acoustic measurements

Abstract

A method includes: outputting at least one test signal (Sn) to a listening environment (30) by means of a loudspeaker (10); receiving each of the at least one test signal (Sn) by means of a microphone (22) arranged in the listening environment (30); determining at least one of a position and an orientation of the microphone (22) relative to the loudspeaker (10) in the listening environment (30) when each of the at least one test signal (Sn) is received; evaluating the test signal (Sn) received by the microphone (22); and determining at least one aspect related to at least one transfer function based on the evaluation of the test signal (Sn) and at least one of the position and the orientation of the microphone.

Description

Technical Field

[0001] The present disclosure relates to a method for performing acoustic measurements, in particular for determining at least one transfer function. Background Art

[0002] When reproducing sound (e.g., music) using an audio system, the reproduced audio content is typically distorted to some extent. The distortion can occur at any point in the audio path from the speaker to the user's ear. This can severely impair the listening experience of the user of the audio system. The audio path or reproduction chain includes several different components, such as the room in which the audio system is installed and the speakers of the audio system. Each component of the reproduction chain introduces a single transfer function, which results in overall distortion. The room transfer function and the speaker transfer function typically have a significant impact on the overall distortion and thus on the sound quality perceived by the user. There is a need to provide a method for performing acoustic measurements on at least one transfer function in order to be able to equalize temporal and spectral distortion during audio reproduction and thus provide a satisfactory sound quality to the user. Summary of the Invention

[0003] The present invention provides a method, which includes: outputting at least one test signal to a listening environment by means of a speaker; receiving each test signal of the at least one test signal by means of a microphone arranged in the listening environment; determining at least one of the position and orientation of the microphone relative to the speaker in the listening environment when each test signal of the at least one test signal is received; evaluating the test signal received by the microphone; and determining at least one aspect related to at least one transfer function based on the evaluation of the test signal and at least one of the position and the orientation of the microphone.

[0004] Other systems, methods, features, and advantages will be apparent or will become apparent to those skilled in the art after reviewing the following detailed description and the drawings. It is intended that all such other systems, methods, features, and advantages be included within this specification, be within the scope of the present invention, and be protected by the accompanying claims. Brief Description of the Drawings

[0005] The method can be better understood with reference to the following description and the drawings. The components in the drawings are not necessarily to scale, but rather emphasize the principles of the present invention. Additionally, the same reference numerals in the drawings designate corresponding parts throughout the different views.

[0006] Figure 1 An exemplary audio system is schematically shown.

[0007] Figure 2 Different transfer functions of an exemplary audio system are schematically shown.

[0008] Figure 3 Another exemplary audio system is schematically shown.

[0009] Figure 4 Another exemplary audio system is schematically shown.

[0010] Figure 5 An exemplary method is schematically shown. DETAILED DESCRIPTION

[0011] Reference Figure 1 , an exemplary audio system is schematically shown. The audio system includes a speaker 10 and a microphone 22. The speaker 10 is arranged in a listening environment 30 and is configured to output an audio signal such as music, speech, or any other kind of audible sound or tone. The microphone 22 is arranged away from the speaker 10 and is configured to receive the audio signal emitted from the speaker 10. In this context, "away" means that there is a distance of at least a few centimeters between the speaker 10 and the microphone 22. In a common listening situation, the speaker 10 is arranged at a position at least 1 m, at least 2 m, or even farther away from the user listening to the audio. The listening position or listening area 32 is defined by the position of the user during audio reproduction. That is, the listening area 32 (or position) is the area (or position) where the user will perceive the audio output by the speaker 10. The listening area 32 (or position) is typically an area smaller than the listening environment 30. The listening area 32 may include the position of the user's head, or particularly the position of the user's ears. When listening to the audio reproduced by the speaker 10, the user is mainly located within the listening area 32. That is, if the user remains stationary at a single position, the listening area 32 is generally smaller compared to the case where the user moves within the listening environment 30. Therefore, in addition to the listening area 32, the listening environment 30 may include other areas where the user is not typically located outside the listening area 32. However, in some cases, if the user moves around frequently, the listening area 32 may cover the entire listening environment 30. In Figure 1 In the example shown, the microphone 22 is arranged at the listening position or within the listening area 32, while the speaker 10 is arranged outside the listening area 32.

[0012] Figure 1The apparatus shown is configured to determine at least one aspect of at least one transfer function. Aspects associated with a transfer function can include at least one of a frequency response, a phase response, an estimated spectral characteristic, an estimated characteristic in terms of time, and a statistical characteristic of the corresponding transfer function. According to one example, only one aspect of at least one transfer function is determined. According to another example, two or more aspects of at least one transfer function are determined. According to yet another example, one or more transfer functions are determined as a whole. In the following, it is assumed that one or more transfer functions are determined as a whole. However, it should be understood that alternatively, only the aspects of the transfer functions mentioned below may be determined. It is also possible to determine at least one aspect of at least one transfer function not specifically mentioned herein.

[0013] When a first audio signal x(t), such as music or speech, is output by the loudspeaker 10, the signal is typically distorted as it propagates along the transmission path from the loudspeaker 10 to the listening area 32. This is because several components within the listening environment 30 introduce different transfer functions, resulting in an overall distortion of the first audio signal x(t). For example, the first audio signal x(t) may be distorted due to the room in which the loudspeaker 10 is arranged or the listening environment 30. The room transfer function H R (jω) typically depends on, for example, the size of the room (listening environment 30), any furniture, plants, or other objects arranged in the room. Such objects can include carpets, bookshelves, curtains, lamps, etc. However, the loudspeaker 10 and the microphone 22 themselves can also introduce additional transfer functions H S (jω) (loudspeaker transfer function), H M (jω) (microphone transfer function).

[0014] Thus, the total transfer function Ht(jω) can be composed of individual transfer functions HS(jω), HR(jω), HM(jω) (for example, see Figure 2 ). According to one example, the following equation applies

[0015] H t (jω) = H s (jω) * H R (jω) * H M (jω) (1)

[0016] That is, the audio signal y(t) captured at the listening position or listening area 32 is a distorted version of the original first audio signal x(t) output by the loudspeaker 10. Thus, a user listening to the audio output by the loudspeaker 10 may experience a disrupted sound experience. Accordingly, many audio systems are configured to determine the total transfer function H t (jω). When the total transfer function H t (jω) or the total transfer function H tWhen at least aspects of (jω) are known, transfer function compensation can be performed when outputting audio. For example, transfer function compensation can include frequency compensation or equalization. A correction filter considering at least one aspect of the transfer function can be applied. Generally, any suitable method for compensating for distortion can be applied.

[0017] Since the transfer function or aspects of the transfer function in a particular situation are usually initially unknown, a measurement sequence can be performed to determine the transfer function or aspects of the transfer function involved. Different methods for measuring the transfer function are generally known. The commonality of all these methods is to use an excitation signal (stimulus) containing all the frequencies of interest to feed the device under test. The response of the device under test is captured and compared with the original signal in an appropriate manner. An excitation signal with high energy can be used to achieve a sufficient signal-to-noise ratio over the entire frequency range of interest. Measurements (or estimations) of the distortion transfer function or aspects of the transfer function can be performed to provide a corresponding compensation filter during subsequent audio playback.

[0018] However, determining the total transfer function considering all the different components within the transmission path can be complex. Many users do not have a dedicated measurement microphone. However, one possibility is to use the microphone 22 arranged in the portable electronic device 20 to determine the transfer function. The portable electronic device 20 can be a mobile phone, smartphone, tablet, laptop, smartwatch, or any other suitable electronic device. Most users today own at least one suitable electronic device 20. Such a portable electronic device 20 usually already has a built-in microphone, which is provided for many different functions of the portable electronic device 20. The test signal Sn can be output by the speaker 10 and received by the microphone 22 of the portable electronic device 20. The portable electronic device 20 or an external computing unit can then evaluate the received signal y(t). Since the original signal x(t) is known, the system can determine the total transfer function generated by the individual transfer functions of the different components in the transmission path.

[0019] However, as mentioned above, the microphone 22 usually introduces an additional transfer function H t (jω) into the total transfer function H M (jω). However, when the user is listening to audio, the microphone 22 is no longer part of the transmission path. The microphone 22 is only involved during the measurement process. Therefore, compensating the total transfer function H M (jω) including the microphone transfer function H t (jω) may not result in a satisfactory listening experience. Compared with the case where no compensation is performed, considering the microphone transfer function H M (jω) during compensation may even lead to a worse listening experience. Therefore, according to one example, determining the microphone transfer function HM (jω) such that it can be subtracted from the total transfer function H t (jω).

[0020] Determining the transfer function of the microphone 22 of the portable electronic device 20 is generally challenging. The microphone 22 of the portable electronic device 20 typically has a directional characteristic. That is, the transfer function of the microphone 22 strongly depends on the orientation of the portable electronic device 20, particularly the orientation of the microphone 22 of the portable electronic device 20. Due to the directional characteristic of the microphone 22, and due to the diffraction and shadow effects of the electronic device 20 itself (e.g., the smartphone housing), the orientation of the electronic device 20 and thus the orientation of the microphone 22 of the electronic device 20 during the measurement process may introduce unpredictable effects on the measurement result.

[0021] However, if the transfer function H M (jω) of the microphone 22 used to perform the test is unknown and this transfer function H M (jω) is not eliminated from the total transfer function H t (jω) considered for transfer function compensation, the user's sound perception may deteriorate.

[0022] Therefore, while performing the test sequence, determine the position and / or orientation of the portable electronic device 20, particularly the microphone 22, relative to the speaker 10. If the position and / or orientation of the microphone 22 is known, the microphone transfer function H M (jω) can be determined accurately enough. That is, when determining the total transfer function H t (jω) or the individual microphone transfer function H M (jω) separately, information regarding the position and / or orientation of the microphone 22 relative to the speaker 10 can be considered.

[0023] Many portable electronic devices 20 standardly include at least one sensor 24 (see Figure 4)。For example, at least one sensor 24 may include at least one of a camera, an acceleration sensor, a motion sensor, a gyroscope, a rotation sensor, a magnetic field sensor, and a proximity sensor. The position and / or orientation of the electronic device 20 may be determined by means of at least one sensor 24 of the electronic device 20. For example, the camera may capture one or more images or videos of the listening environment 30 in which the speaker 10 is arranged. The position and / or orientation of the microphone 22 relative to the speaker 10 may then be determined by means of a suitable image processing method. For example, the captured images or videos may be analyzed, and the speaker 10 may be identified in the images or videos by means of object recognition or computer vision techniques. Generally, different techniques are known that allow performing edge detection, gradient matching, or similar techniques capable of identifying objects in images or videos. For example, the acceleration or motion sensor may provide information about the orientation of the microphone 22. The proximity sensor may determine the distance of the portable electronic device 20 relative to any object within the listening environment 30. Any other suitable sensor 24 may be used to determine the position and / or orientation of the microphone 22 relative to the speaker 10.

[0024] Compared to the case where the microphone 22 is pointed towards the speaker 10, the transfer function H M (jω) of the microphone 22 may be completely different. Therefore, knowledge of the orientation of the microphone 22 relative to the speaker 10 helps to determine the microphone transfer function H M (jω) and improve the user's listening experience.

[0025] Before actually listening to the desired audio output by the speaker 10, the user may perform a measurement process. The user may position himself in the desired listening area 32. When the speaker 10 generates at least one test signal Sn, the user may hold the portable electronic device 20 in his hand. Figure 3 An exemplary test sequence is schematically shown. According to one example, a single test signal S1 may be output by the speaker 10 and captured by the microphone 22 at a single test position P1. According to other examples, multiple test signals Sn may be output continuously. Between different test signals Sn, the user may move the electronic device 20 with the microphone 22 to different test positions Pn. In this way, the test signals Sn may be received at different test positions Pn within the listening area 32. Then, the determined measurement results from each of the multiple test positions Pn may be averaged. Later, when determining the microphone transfer function H MThe average value can be considered when equalizing distortion during audio reproduction at (jω). This brings a satisfactory listening experience to the user throughout the listening area 32. If the user remains stationary at a single listening position 32, a single test measurement (test signal S1 at test position P1, where test position P1 corresponds to listening position 32) may be sufficient. However, if the user intends to move around the listening area 32, more than one test measurement may be performed to improve the listening experience throughout the listening area 32.

[0026] The different test signals Sn of the test sequence can be the same. For example, each test signal can be output for a period of time, e.g., a single test signal Sn can be output for 0.5 seconds to several seconds. Generally, the test signal Sn should be long enough for the user to hear it and accordingly locate the electronic device 20. There can be a pause between different test signals Sn, which allows the user to reposition the electronic device 20. Each pause can last, for example, 1 second or longer. According to one example, the user moves the electronic device 20 to the next test position Pn and remains stationary during the duration of the corresponding test signal Sn. However, according to another example, it is also possible for the user to perform a single continuous movement. That is, the user can move the electronic device 20 in a single continuous movement, thus moving the electronic device 20 past all the required test positions Pn, yet without actually pausing at the different test positions Pn. According to one example, the user moves the electronic device once around their head. It is also possible to output only a single test signal S1. For example, this single test signal S1 can have a length of several seconds. When outputting this single test signal S1, the user can move the electronic device 20 to different measurement positions Pn. Any suitable type of test signal Sn can be used, such as a noise or a sweep signal. The type of test signal Sn is generally independent of the measurement being performed.

[0027] For example, the number of test signals Sn and test positions Pn can depend on the size of the listening area 32. That is, if the user remains substantially stationary while listening to the audio, performing a test sequence at fewer test positions Pn with fewer test signals Sn may be sufficient to determine the corresponding transfer function. If the user intends to move around a relatively large listening area 32, the number of required test signals Sn and test positions Pn may be greater.

[0028] Difficulties arise if the electronic device 20 does not move from one measurement position Pn to another at a constant speed. The change in speed may have a negative impact on the measurement results. It is also possible for the user to still move the electronic device 20 in the case where the electronic device 20 is required to remain stationary at the test position Pn during the output of the corresponding test signal Sn.

[0029] According to an example, a corresponding application (app) is installed on the electronic device 20. This application can be used to initiate a test sequence. The user can open the application and press the corresponding button to start the test sequence. For example, the electronic device 20 can communicate with the speaker 10 via a wired or wireless communication link. The speaker 10 can be a speaker external to the electronic device 20. The portable electronic device 20 can cause the speaker 10 to output at least one test signal Sn, for example, by sending a corresponding signal to the speaker 10. However, alternatively, another external device may also be involved in this process, which communicates with the electronic device 20 and the speaker 10 and instructs the speaker 10 to output at least one test signal Sn. Once the test sequence has started, the application can provide instructions to the user on how to move the electronic device 20. For example, the instructions can be visually output via the display of the electronic device 20, or output as verbal instructions via the speaker. The application can indicate how fast the user should move the electronic device. For example, an arrow indicating the direction in which the electronic device 20 is to be moved can be shown on the display. For example, such an arrow can be represented in different colors. Green can indicate that the user is moving the electronic device at the desired speed. For example, red may indicate that the movement is too slow or too fast. The length, thickness, or intensity of the arrow can indicate whether the electronic device is moving too slow or too fast. However, this is only an example. Any other visual, auditory, or tactile indicator can be used to guide the user on how to move the electronic device 20.

[0030] According to an example, the camera of the electronic device 20 can be configured to record the surrounding environment of the electronic device 20. An image or video of the captured surrounding environment can be shown on the display of the electronic device 20. For example, the user may be required to move the electronic device 20 in such a way that the speaker 10 is always captured by the camera during the test sequence. For example, the speaker 10 can be highlighted on the display. That is, a graphical marker (e.g., a circle, arrow, or cross) can be shown on the display at or near the position of at least one speaker 10. If the speaker 10 is no longer captured by the camera and no marker appears on the display, the user can inform that the orientation of the electronic device 20 is incorrect. If the orientation of the electronic device 20 is incorrect, the electronic device may also output a warning. For example, this can be a visual, auditory, or tactile warning. In this way, it can be ensured that the orientation and position of the speaker 22 are correct during the test sequence.

[0031] According to another example, no warning is generated during the test sequence. It is also possible to notify the user after the test sequence is completed that the test sequence has not been executed correctly. For example, the user may need to repeat the test sequence.

[0032] At least one sensor 24 may be configured to monitor the position and / or orientation of the electronic device 20 throughout the test sequence. The position and / or orientation may be monitored continuously throughout the test sequence. The position and / or orientation may also be monitored at prescribed time intervals throughout the test sequence. In this way, it can be determined whether the microphone 22 is pointing in the wrong direction during the test sequence. For example, this may occur if the user tilts the electronic device 20 too far in one direction such that the microphone 22 no longer points sufficiently at the speaker 10.

[0033] According to one example, the orientation of the microphone 22 is determined throughout the test sequence. Then, the information regarding the orientation of the microphone 22 during the test sequence can be used to compensate the microphone transfer function H M (jω) for each time point of the measurement sequence. In this case, knowledge of the direction-dependent microphone transfer function H M (jω) may be required. That is, for certain orientations of the microphone 22 relative to the speaker 10, the corresponding microphone transfer function H M (jω) may be known. For example, information about different transfer functions for different orientations may be stored in the electronic device 20. For example, one transfer function may be associated with different orientations of the microphone 22 that fall within a defined angular range (e.g., the angle between the main radiation direction of the speaker 10 and the main reception direction of the directional microphone). The smaller the angular range, the higher the compensation accuracy.

[0034] In many cases, more than one speaker 10 of the audio system is visible in the image captured by the camera of the electronic device 20. In this case, the system may not know which speaker 10 generates the test signal Sn. In this case, the application may prompt the user to indicate which speaker 10 will be used in the test sequence. If more than one speaker 10 is arranged in the listening environment 30, a separate test sequence may be performed for each of the different speakers 10 subsequently used for outputting audio.

[0035] If the position and orientation of the microphone 22 are substantially constant throughout the test sequence, the transfer function H M (jω) of the microphone 22 (or the electronic device 20) is determined. This allows for the full determination of the microphone transfer function H M (jω) and the compensation of the determined microphone transfer function H M(jω). Typically, the manufacturer of the electronic device 20 or the audio system may also pre - perform a test sequence (e.g., in an anechoic chamber) and provide information about the transfer function of the electronic device 20 or the microphone 22, which can be considered during subsequent audio processing. During subsequent audio processing, information about the directivity of the microphone 22 can also be considered. For example, such directivity information can be provided by the manufacturer of the microphone 22 and can be stored in the electronic device 20. Signal processing during audio reproduction can then compensate for the microphone directivity for a particular orientation of the given microphone 22 at that particular time point during measurement.

[0036] Now referring to Figure 5 , an exemplary method is schematically illustrated in the sequence diagram. The method includes outputting at least one test signal to a listening environment by means of a loudspeaker (step 501); receiving each of the at least one test signal by means of a microphone arranged in the listening environment (step 502); determining at least one of the position and orientation of the microphone relative to the loudspeaker in the listening environment when each of the at least one test signal is received (step 503); evaluating the test signal received by the microphone (step 504); and determining at least one aspect related to at least one transfer function based on the evaluation of the test signal and at least one of the position and orientation of the microphone (step 505).

[0037] At least one aspect related to at least one transfer function may include at least one of a frequency response, a phase response, an estimated spectral characteristic, an estimated characteristic in terms of time, and a statistical characteristic of the corresponding transfer function.

[0038] Determining at least one aspect related to at least one transfer function may include determining at least one transfer function.

[0039] Evaluating the test signal may include determining a change in at least one parameter of at least one test signal that occurs on the transmission path between the loudspeaker and the microphone.

[0040] Evaluating the test signal may include determining a change in the frequency response of at least one test signal that occurs on the transmission path between the loudspeaker and the microphone.

[0041] Outputting at least one test signal may include outputting a plurality of subsequent test signals, where each test signal is received by the microphone at different test positions within the listening environment, or outputting a single continuous test signal within a defined time length, where the single continuous test signal is received by the microphone at different test positions within the listening environment.

[0042] A microphone may be arranged in a portable electronic device, the portable electronic device including a user interface, and the method may further include outputting at least one command via the user interface to provide an instruction to a user of the portable electronic device regarding at least one of a position, an orientation, a moving speed, and a moving route of the microphone at or between different test positions.

[0043] The user interface may include a display, and the method may further include capturing at least one image or video of a listening environment and a speaker arranged in the listening environment by means of at least one camera of the electronic device, displaying the at least one image or the video of the listening environment and the speaker on a display of the electronic device, and marking a position of the speaker in the displayed image or video.

[0044] Marking a position of the speaker in the listening environment on the display may include presenting a graphical mark at or near the position of the speaker on the display.

[0045] The method may further include, when a test signal is received, comparing a position and / or an orientation of the microphone in the listening environment relative to the speaker with a desired position and / or orientation, and generating a warning if the actual position and / or orientation does not correspond to the desired position and / or orientation.

[0046] The warning may include at least one of a visual warning, an auditory warning, and a tactile warning.

[0047] When a test signal is received, a position and / or an orientation of the microphone in the listening environment relative to the speaker may be determined by means of at least one sensor of the portable electronic device.

[0048] The at least one sensor may include at least one of a camera, an acceleration sensor, a motion sensor, a gyroscope, a rotation sensor, a magnetic field sensor, and a proximity sensor.

[0049] The at least one transfer function may be a transfer function of the microphone.

[0050] Evaluating a test signal received by at least one microphone may include evaluating each of the received test signals separately to generate a plurality of evaluation results, and averaging the evaluation results of the respective test signals.

[0051] It will be understood that the methods and systems shown are merely examples. Although various embodiments of the present invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the present invention. In particular, those skilled in the art will recognize the interchangeability of various features of different embodiments. Although these techniques and systems have been disclosed in the context of certain embodiments and examples, it should be understood that these techniques and systems can be extended beyond the specifically disclosed embodiments to other embodiments and / or uses and their obvious modifications. Thus, the present invention is not limited except as by the appended claims and their equivalents.

[0052] For purposes of illustration and description, a description of the embodiments has been presented. Appropriate modifications and variations of the embodiments may be made in light of the above description, or such modifications and variations may be obtained from practicing these methods. The described apparatus is exemplary in nature and may include additional elements and / or omit elements. As used in this application, an element recited in the singular and preceded by the word "a" or "an" should be understood as not excluding the plural of such element, unless such exclusion is stated. Additionally, a reference to "one embodiment" or "an example" of the present disclosure is not intended to be construed 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. The described system is 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 various systems and configurations, as well as the other features, functions, and / or properties disclosed. The following claims particularly point out the subject matter that is regarded as novel and non-obvious in the above disclosure.

Claims

1. A method for performing an acoustic measurement, comprising: Outputting at least one test signal (Sn) to a listening environment (30) by means of a loudspeaker (10); Receiving each of the at least one test signal (Sn) by means of a microphone (22) arranged in the listening environment (30); Determining at least one of a position and an orientation of the microphone (22) relative to the loudspeaker (10) in the listening environment (30) when each of the at least one test signal (Sn) is received; Evaluating each of the at least one test signal (Sn) received by the microphone (22); Determine at least one aspect related to at least one transfer function based on the evaluation of each of the at least one test signal (Sn) and at least one of the position and the orientation of the microphone (22), wherein the at least one transfer function is the transfer function (H M (jω)); Comparing the position and / or the orientation of the microphone (22) relative to the loudspeaker (10) in the listening environment with a desired position and / or orientation when a test signal (Sn) is received; And Generating a warning if the actual position and / or orientation does not correspond to the desired position and / or the orientation.

2. The method according to claim 1, wherein the at least one aspect related to at least one transfer function includes at least one of a frequency response, a phase response, an estimated spectral characteristic, an estimated characteristic in terms of time, and a statistical characteristic of the corresponding transfer function.

3. The method according to claim 1, wherein determining at least one aspect related to at least one transfer function includes determining the at least one transfer function.

4. The method according to claim 1, wherein evaluating the test signal (Sn) includes determining a change in at least one parameter of the at least one test signal (Sn) occurring on a transmission path between the loudspeaker (10) and the microphone (22).

5. The method according to claim 4, wherein evaluating the test signal (Sn) includes determining a change in a frequency response of the at least one test signal (Sn) occurring on the transmission path between the loudspeaker (10) and the microphone (22).

6. The method according to claim 1, wherein outputting at least one test signal (Sn) includes Outputting a plurality of subsequent test signals (Sn), wherein each test signal (Sn) is received by the microphone (22) at different test positions (Pn) within the listening environment (30); or Outputting a single continuous test signal (Sn) within a defined time length, wherein the single continuous test signal (Sn) is received by the microphone (22) at different test positions (Pn) within the listening environment (30).

7. The method according to claim 6, wherein the microphone (22) is arranged in a portable electronic device (20), the portable electronic device (20) includes a user interface, and wherein the method further includes Outputting at least one command via the user interface to provide an instruction to a user of the portable electronic device regarding at least one of a position, an orientation, a moving speed, and a moving route of the microphone (22) at or between the different test positions (Pn).

8. The method according to claim 7, wherein the user interface includes a display, and wherein the method further comprises capturing, by means of at least one camera of the electronic device (20), at least one image or video of the listening environment (30) and the loudspeaker (10) arranged in the listening environment (30); displaying, on the display of the electronic device (20), the at least one image or the video of the listening environment (30) and the loudspeaker (10); and marking the position of the loudspeaker (10) in the displayed image or video.

9. The method according to claim 8, wherein marking the position of the loudspeaker (10) in the listening environment (30) on the display includes presenting a graphical mark at or near the position of the loudspeaker (10) on the display.

10. The method according to claim 1, wherein the warning includes at least one of a visual warning, an audible warning, and a tactile warning.

11. The method according to claim 7, wherein, upon receiving the test signal (Sn), the position and / or the orientation of the microphone (22) relative to the loudspeaker (10) in the listening environment is determined by means of at least one sensor (24) of the portable electronic device (20).

12. The method according to claim 11, wherein the at least one sensor (24) includes at least one of a camera, an acceleration sensor, a motion sensor, a gyroscope, a rotation sensor, a magnetic field sensor, and a proximity sensor.

13. The method according to any one of the preceding claims, wherein evaluating the test signal (Sn) received by the microphone (22) includes evaluating each of the received test signals (Sn) separately, thereby generating a plurality of evaluation results; and averaging the evaluation results of the respective test signals (Sn).

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