EP3917170A1 - Testing device for testing a microphone - Google Patents

Abstract

The invention relates to a test device (1) for testing a microphone (2) with at least one test loudspeaker (3) for generating at least one test tone (4), with at least one test cavity (5) into which the test tone (4) can be emitted, with at least one receiving area (7) for receiving the microphone (2) to be tested, which is designed such that the microphone (2) to be tested can be acoustically coupled to the test cavity (5), and with at least one reference microphone (8) for Determining a reference signal of the test tone (4) emitted by the test loudspeaker (3). According to the invention, the test device (1) has a reference cavity (13) which is separate from the test cavity (5), into which the test tone (4) can also be emitted and to which the reference microphone (8) is acoustically coupled to determine the reference signal, and / or that the receiving area (7) is arranged on a first side (6) of the test loudspeaker (3) and the reference microphone (8) is arranged on a second side (9) of the test loudspeaker (3) opposite the first side (6).

Description

The present invention relates to a test device for testing a microphone with at least one test loudspeaker for generating at least one test tone, with at least one test cavity into which the test loudspeaker can emit the test tone, with at least one receiving area for receiving the microphone to be tested, which is designed in such a way that the microphone to be tested can be acoustically coupled to the test cavity, and with at least one reference microphone for determining a reference signal of the test tone emitted by the test loudspeaker.

From the WO 2016/111983 A1 a test system for a microphone is known. The test device comprises a test loudspeaker which can send a test tone into a test chamber. The microphone to be tested and a reference microphone are arranged in the test chamber.

The object of the present invention is therefore to improve the state of the art.

The object is achieved by a test device with the features of the independent claim.

A test device for testing a microphone is proposed. This can be used, for example, to check whether the microphone is picking up a sound in a distorted manner, so that this non-functional microphone can be rejected.

The test device comprises at least one test loudspeaker for generating at least one test tone. The test loudspeaker can also be used to generate a test sequence which contains several test tones of different frequencies and / or volume levels. The test tone is recorded by the microphone to be tested, which then generates a signal. This signal can be evaluated in order to check the correct functioning of the microphone.

Furthermore, the test device comprises at least one test cavity into which the test loudspeaker can emit the test tone.

The test device comprises at least one receiving area for receiving the microphone to be tested, which is designed such that the microphone to be tested can be acoustically coupled to the test cavity. When the microphone to be tested is thus inserted into the test device, the microphone is in acoustic connection with the test cavity. The microphone to be tested can thus be coupled to the test cavity. The microphone to be tested can thus detect the test tone in the test cavity. When the microphone to be tested is arranged in the receiving area, it is thus connected to the test cavity or is coupled to the test cavity. For example, the receiving area is part of the test cavity and / or, for example, the receiving area delimits the test cavity. The receiving area can also be arranged in such a way that the microphone to be tested, when it is located in the receiving area, is arranged in the test cavity. If the microphone under test is in the pickup area, it can pick up the test tone.

In addition, the test device comprises at least one reference microphone for determining a reference signal of the test tone emitted by the test loudspeaker. The reference microphone can be used, for example, to check whether the test loudspeaker has emitted the correct test tone. For example, the test loudspeaker itself could be defective, which can be checked with the reference microphone.

According to the invention, the test device has a reference cavity which is separate from the test cavity, into which the test tone can also be emitted and to which the reference microphone is acoustically coupled for determining the reference signal. As a result, the microphone to be tested can detect the test tone in the test cavity and the reference microphone can detect the test tone in the reference cavity. The two measurements are thus decoupled from one another so that they do not, or only slightly, influence one another.

Additionally or alternatively, it is according to the invention that the recording area is arranged on a first side of the test loudspeaker and the reference microphone is arranged on a second side of the test loudspeaker opposite the first side. The test loudspeaker is thus arranged between the reference microphone and the recording area and the microphone to be tested when this is located in the recording area. The test loudspeaker is thus also arranged between the reference microphone and the test cavity. As a result, the test device has a compact design when the microphone to be tested is arranged in the receiving area.

Due to the arrangement of the reference microphone on the second side of the test loudspeaker, a sandwich construction is formed, which also results in a compact construction.

The test cavity can thus be arranged on the first side of the test loudspeaker and the reference cavity on the second side of the test loudspeaker.

It is advantageous if the test loudspeaker is designed in such a way that it can emit the test tone in the direction of its first side and in the direction of its second side. Additionally or alternatively, it is advantageous if the test loudspeaker is designed in such a way that it emits the test tone into the Test cavity and can emit into the reference cavity. Additionally or alternatively, it is advantageous if the test loudspeaker is arranged in such a way that it can emit the test tone in the direction of its first side and in the direction of its second side. As a result, the test tone is sent to the microphone under test and the reference microphone. The microphone to be tested and the reference microphone thus both record the same test tone, so that the two recorded signals can be compared.

It is advantageous if the reference cavity is arranged on the second side of the test loudspeaker.

It is advantageous if the test loudspeaker comprises a membrane by means of which the test tone can be transmitted into the test cavity. Additionally or alternatively, the membrane can also emit the test tone into the reference cavity. The membrane is set in oscillation, so that the air in the test cavity and / or in the reference cavity is set in oscillation and, as a result, the test tone is formed.

The membrane can be arranged between the test cavity and the reference cavity. By vibrating the membrane, the test tone is generated in the test cavity and the reference cavity at the same time. Additionally or alternatively, the membrane can also separate the test cavity and the reference cavity from one another. As a result, the acoustic properties of one cavity have no effect on the other cavity.

It is advantageous if the test device has a recording device for receiving the microphone to be tested, which has the recording area. The receiving device can be arranged on the first side of the test loudspeaker. The recording device can, for example, have a recess in which the microphone to be tested can be arranged. The receiving device and / or the recess can be designed in such a way that they can pick up the microphone to be tested.

Furthermore, the recording device can preferably have a fixing device in order to be able to fix the microphone to be tested. This can prevent the microphone from becoming detached from the test device during testing.

Additionally or alternatively, the test device can also have the fixing device.

The microphone to be tested can also be fixed in a non-positive and / or form-fitting manner by means of the fixing device. The fixing device can for example comprise a spring element, by means of which the microphone to be tested is fixed.

It is advantageous if the test cavity is formed at least partially by means of a front volume of the test loudspeaker. Additionally or alternatively, the test cavity can be formed at least partially by means of a passage of the receiving device and / or the receiving area. Additionally or alternatively, the test cavity can be formed at least partially by means of a first detection volume of the microphone to be tested. This means that existing volumes can be used.

It is advantageous if the reference cavity is at least partially formed by a rear volume of the test loudspeaker. Additionally or alternatively, the reference cavity can also be formed by a second detection volume of the reference microphone. This means that existing volumes can be used.

It is advantageous if the test cavity and the reference cavity are spaced apart from one another in an axial direction of the test device. Additionally or alternatively, it is advantageous if the at least one test loudspeaker is arranged between the test cavity and the reference cavity.

It is advantageous if the front volume, the passage of the receiving device and / or the receiving area and / or the first acquisition volume are arranged coaxially, in particular congruently, with one another. It should be noted here and also for the following description that the first detection volume belongs to the microphone to be tested. No or only little influence can therefore be exerted on the formation of the first acquisition volume. Rather, however, said volumes and / or the passage can be adapted to the first acquisition volume. The front volume and / or the passage can be designed in such a way that they are arranged coaxially with the first detection volume, in particular congruent with one another, when the microphone to be tested is being tested. Due to the coaxial and / or congruent design, for example, scattering at edges can be avoided.

Additionally or alternatively, the rear volume and the second acquisition volume can be arranged coaxially, in particular congruently, with one another. In this way, as described above, for example, scatter can be reduced. In this way, too, scatter can be avoided.

Additionally or alternatively, the front volume, the passage, the rear volume, the first and / or the second acquisition volume can have a round cross section.

It is advantageous if the front volume, the passage, the first acquisition volume and / or the membrane are arranged offset to one another in the transverse direction. Additionally or alternatively, the rear volume, the second acquisition volume and / or the membrane can be arranged offset to one another in the transverse direction.

It is advantageous if the membrane of the at least one test loudspeaker is arranged oriented in the transverse direction. In addition, the membrane of the at least one test loudspeaker can extend transversely, in particular perpendicular, to the axial direction. As a result, the generated sound waves are radiated in the axial direction.

It is advantageous if the membrane has a larger area than a cross-sectional area of the front volume. The surface of the membrane or the membrane itself and the cross-sectional area can be parallel to one another. Additionally or alternatively, the membrane can also have a larger area than a cross-sectional area of the passage. Additionally or alternatively, the membrane can also have a larger area than a cross-sectional area of the rear volume. Additionally or alternatively, the membrane can also have a larger area than a cross-sectional area of the test cavity. Additionally or alternatively, the membrane can also have a larger area than a cross-sectional area of the reference cavity. Additionally or alternatively, the membrane can also have a larger area than a cross-sectional area of the first acquisition volume. Additionally or alternatively, the membrane can also have a larger area than a cross-sectional area of the second acquisition volume. The cross-sectional areas of the said volumes or cavities can be parallel to one another. The area of the membrane can preferably mean the area which faces the corresponding volume or the corresponding cavity. This has the advantage, explained using the passage as an example, that the membrane is larger than the passage, so that the sound waves generated by the membrane have to pass through the smaller passage, the sound pressure increasing.

It is advantageous if a volume of the front volume is greater than a volume of the passage. Additionally or alternatively, it is advantageous if the volume of the front volume is greater than a volume of the first acquisition volume.

Additionally or alternatively, it is advantageous if a volume of the rear volume is greater than a volume of the second acquisition volume. Due to the larger volume of the front volume compared to the passage or the first detection volume, a sound pressure generated by the test loudspeaker is increased when the sound reaches the passage or the first detection volume from the front volume. The same applies to the rear volume and the second acquisition volume. As a result, high sound pressures can be generated for testing the microphone.

It is advantageous if at least two test loudspeakers are arranged one above the other in an axial direction of the test device. This can increase the test tone.

It is advantageous if, in the case of two test loudspeakers arranged one above the other, the rear volume of one test loudspeaker is arranged coaxially, in particular congruently, with one another with the front volume of the other test loudspeaker. In this way, for example, scatter can in turn be reduced.

It is advantageous if the at least one test loudspeaker, the at least one reference microphone and / or the at least one recording device are arranged in a housing. Furthermore, the receiving device and the housing can also be designed in one piece.

It is advantageous if several microphones can be tested by means of the test device. This means that a large number of microphones can be tested at the same time. Additionally or alternatively, several microphones can be recorded in the recording area, for example.

It is advantageous if, in order to test a plurality of microphones, the test device has a plurality of recording areas, a plurality of test loudspeakers, a plurality of test cavities, a plurality of reference microphones and / or a plurality of reference cavities. The elements required for testing a microphone are duplicated so that several microphones can be tested at the same time. To test a plurality of microphones, the test device can be designed, for example, in such a way that the microphones can be arranged next to one another, in particular flat. For example, several receiving areas can be arranged next to one another, in particular flat, for this purpose.

It is advantageous if the microphone to be tested is a MEMS microphone.

Additionally or alternatively, the at least one test loudspeaker can be a MEMS loudspeaker and / or an electrodynamic loudspeaker.

Additionally or alternatively, the at least one reference microphone can be a MEMS microphone, an electrostatic microphone and / or condenser microphone.

Figur 1

eine schematische Schnittansicht einer Testvorrichtung zum Testen eines Mikrofons,

Figur 2

eine schematische Schnittansicht einer Testvorrichtung zum Testen eines Mikrofons mit zwei Testlautsprechern,

Figur 3

eine schematische Schnittansicht einer Testvorrichtung zum Testen von mehreren Mikrofonen und

Figur 4

eine schematische Schnittansicht einer Testvorrichtung zum Testen eines Mikrofons.

Further advantages of the invention are described in the following exemplary embodiments. Show it:

Figure 1

a schematic sectional view of a test device for testing a microphone,

Figure 2

a schematic sectional view of a test device for testing a microphone with two test speakers,

Figure 3

a schematic sectional view of a test device for testing a plurality of microphones and

Figure 4

a schematic sectional view of a test device for testing a microphone.

Figure 1 shows a schematic sectional view of a test device 1 for testing a microphone 2. For better explanation, the microphone 2 to be tested is arranged or inserted into the test device 1 here.

The test device 1 has an axial direction X and a transverse direction Y perpendicular thereto.

The test device 1 comprises at least one test loudspeaker 3 for generating a test tone 4. The test tone 4 is detected by the microphone 2 to be tested. As a result, an evaluation can be used to determine whether the microphone 2 is functioning correctly. For example, the microphone 2 could pick up sounds in a distorted manner, so that the microphone 2 cannot be used.

The test device 1 further comprises at least one test cavity 5 into which the test loudspeaker 3 can emit the test tone 4. In the exemplary embodiment shown here, the test cavity 5 is arranged on a first side 6 of the test loudspeaker 3.

In addition, the test device 1 comprises at least one receiving area 7 for receiving the microphone 2 to be tested. The receiving area 7 is designed such that the microphone 2 to be tested can be acoustically coupled to the test cavity 5. In this exemplary embodiment, the receiving area 7 also faces the first side 6 of the test loudspeaker 3 or is arranged on the first side 6. The microphone 2 to be tested, when it is located in the test device 1, and the test cavity 5 are thus arranged on the same side, namely the first side 6, of the test loudspeaker 3.

The receiving area 7 is further arranged and / or designed in such a way that when the microphone 2 to be tested is arranged in the receiving area 7, the microphone 2 is coupled and / or connected to the test cavity 5. The microphone 2 to be tested can thus detect the test tone 4 emitted by the test loudspeaker 3 into the test cavity 5.

Furthermore, the test device 1 can have an upper side 22 and an underside 23. For example, the receiving area 7 and the microphone 2 to be tested are arranged on the upper side 22. The reference microphone 8 is arranged on the underside 23, for example.

According to the present exemplary embodiment, the test device 1 has a receiving device 19 which has the receiving region 7. The recording device 19 can, for example, have a recess 20 shown here, in which the microphone 2 to be tested can be received in a form-fitting manner at least in the transverse direction Y. The recording device 19 and / or the test device 1 can also have a fixing device, not shown here, by means of which the microphone 2 to be tested can be fixed in the recording area 7, in particular in a force-fitting and / or form-fitting manner.

On the basis of an evaluation of the signal detected by the microphone 2 to be tested, it can be determined whether the microphone 2 is functioning as intended.

The test tone 4 can of course have several frequencies, a frequency profile, different volume levels and / or a volume profile in order to test the microphone 2 at different frequencies and / or at different volume levels. Rather, the test tone 4 is not just a single tone of a frequency, but a sequence of tones of the most varied of volume levels. A test sequence can of course last a few seconds or more. The test loudspeaker can thus also generate the test sequence. The test tone 4 can be a test sequence.

Furthermore, the test device 1 has a reference microphone 8. The reference microphone 8 represents a reference. The reference microphone 8 can also be used to check whether the test loudspeaker 3 has emitted the test tone 4 provided. A reference signal of the test tone 4 emitted by the test loudspeaker 3 can thus be determined by means of the reference microphone 8. The reference signal can then be compared with the signal detected by the microphone 2 to be tested. If, for example, the two signals match, it can be concluded that the microphone 2 to be tested is functioning correctly.

In the exemplary embodiment shown here, the reference microphone 8 is arranged on a second side 9 of the test loudspeaker 3. The second side 9 is arranged on the side of the test loudspeaker 3 opposite to the first side 6.

As a result, the microphone 2 to be tested, when it is in the test device 1, is arranged on the first side 6 of the test loudspeaker 3 and the reference microphone 8 is arranged on the opposite second side 9 of the test loudspeaker 3. As a result, the test device 1 with the microphone 2 can be made compact. As a result, a sandwich construction is also formed, which is space-saving. Furthermore, this design has the advantage that the test device 1 only has to be open on the first side 6 or the top 22 or has to be designed there in such a way that the test device 1 can be opened there in order to connect the microphone 2 to be tested to be able to use the receiving area 7. The reference microphone 8 and / or the test loudspeaker 3 or the test device 1 can be encapsulated on the second side 9 or on the underside 23.

The test loudspeaker 3 also has a membrane 10, which can set the surrounding air vibrating, so that sound waves and thus the test tone 4 can be formed. The membrane 10 can be deflected along a stroke axis H. For this purpose, the test loudspeaker 3 has an actuator, not shown here, for example a piezo actuator. As shown here, the membrane 10 can oscillate in the direction of the first side 6 and the second side 9. The stroke axis H is oriented parallel to the axial direction X in this exemplary embodiment.

Furthermore, the test loudspeaker 3 and / or the membrane 10 is oriented in the transverse direction Y. As a result, the sound formed by the test loudspeaker 3 and / or by the diaphragm 10 can be emitted in the axial direction X. The test loudspeaker 3 and / or the membrane 10 extend transversely, in particular perpendicularly, to the axial direction X of the test device 1.

According to the present exemplary embodiment, the test loudspeaker 3 is designed in such a way that it can form the test tone 4, which has two test tone components 11, 12. According to the present exemplary embodiment, a first test tone component 11 is emitted or emitted in the direction of the first side 6 of the test loudspeaker 3 and a second test tone component 12 in the direction of the second side 9 of the test loudspeaker 3. The first test tone component 11 is thus directed in the direction of the microphone 2 to be tested. In contrast, the second test tone component 12 is directed in the direction of the reference microphone 8.

The two test tone components 11, 12 are essentially the same as one another. Their amplitude can only be inverted. If the membrane 10 deflects to one of the two sides 6, 9, an overpressure occurs there, which is reflected in the amplitude of the sound waves. On the other hand, a negative pressure is formed on the opposite side 6, 9, which is also reflected in the amplitude of the sound waves, but correspondingly in the opposite direction. This can be taken into account when evaluating the reference signal with the signal from the microphone 2 to be tested.

The first test tone component 11 shown here is also transmitted or emitted into the test cavity 5.

According to the present exemplary embodiment, the test device 1 has a reference cavity 13. The test tone 4 can likewise be emitted or radiated into the reference cavity 13. The reference microphone 8 is also acoustically coupled to the reference cavity 13 in order to be able to detect the test tone 4 arranged therein. The second test tone component 12 shown here is transmitted into the reference cavity 13.

The reference cavity 13 is arranged here on the side of the test loudspeaker 3 opposite to the test cavity 5. The reference cavity 13 is arranged on the second side 9 of the test loudspeaker 3.

Furthermore, as shown in this exemplary embodiment, the diaphragm 10 of the test loudspeaker is arranged between the test cavity 5 and the reference cavity 13. The membrane 10 can also separate the test cavity 5 and the reference cavity 13 from one another, in particular in an airtight manner.

According to the present exemplary embodiment, the test loudspeaker 3 also has a front volume 14. The test cavity 5 is here at least partially formed by the front volume 14.

In addition, the receiving device 19 has a passage 15. Additionally or alternatively, the test cavity 5, as shown here, can be formed at least partially by the passage 15. The passage 15 also forms a volume.

Additionally or alternatively, the microphone 2 to be tested also has a first acquisition volume 16. Additionally or alternatively, the test cavity 5, as shown here, can be formed at least partially by the first acquisition volume 16.

According to the present exemplary embodiment, the front volume 14, the passage 15 and the first acquisition volume 16 form the test cavity 5.

It is advantageous if, as shown here, the front volume 14, the passage 15 and / or the first acquisition volume 16 are coaxial and / or congruent with one another. This avoids edges between the transitions which, for example, would scatter the sound waves. Since the first acquisition volume 16 belongs to the microphone 2 to be tested, the front volume 14 and / or the passage 15 can also be adapted to the first acquisition volume 16.

Furthermore, the test loudspeaker 3 according to the present exemplary embodiment has a rear volume 17. The reference cavity 13 is here at least partially formed by the rear volume 17.

The reference microphone 8 also has a second detection volume 18. Additionally or alternatively, the reference cavity 13 can be formed by the second acquisition volume 18.

According to the present exemplary embodiment, the reference volume 13 is formed by the rear volume 17 and the second acquisition volume 18.

According to the present exemplary embodiment, the test device 1 has a housing 21. As shown here, the test loudspeaker 3 and the reference microphone 8 are accommodated in the housing 21. The housing 21 is also connected to the receiving device 19. The housing 21 can, however, also have the receiving area 7. The housing 21 can also extend completely over the underside 23, so that, for example, the reference microphone 8 is also encapsulated.

It is also advantageous if the test cavity 5 and / or the reference cavity 13 are made as small as possible. As a result, a sound pressure in the test cavity 5 and / or the reference cavity 13 is increased so that the microphone 2 can be tested better and / or the reference microphone 8 can determine stronger signals.

Features that have already been described in the previous figure are not explained again for the sake of simplicity. Furthermore, features can only be described in the following figures. Furthermore, for the sake of simplicity, the same reference symbols are used for the same features. In addition, for the sake of clarity, not all features can be shown in the following figures. However, features shown in one or more of the preceding figures can also be present in one or more of the following figures. Furthermore, for the sake of clarity, features can also only be shown in one or more of the following figures. Nonetheless, features which are only shown in one or more of the following figures can also already be present in a previous figure.

Figure 2 shows a test device 1 for testing the microphone 2 with two test speakers 3a, 3b.

According to the present exemplary embodiment, the two test speakers 3a, 3b are arranged one above the other in the axial direction X. As a result, a sound pressure in the test cavity 5 can be increased.

The two test speakers 3a, 3b each have a membrane 10a, 10b. The first diaphragm 10a can be deflected along the first stroke axis H1 and the second diaphragm 10b along the second stroke axis H2. Both stroke axes H1, H2 are oriented parallel to one another. When operating the two test speakers 3a, 3b, it is advantageous if both membranes 10a, 10b move synchronously so that the sound waves generated move strengthen. The two stroke axes H1, H2 are again arranged parallel to the axial direction X here.

The first and / or the second test loudspeaker 3a, 3b has the front volume 14a, 14b and / or a rear volume 17a, 17b.

According to the present exemplary embodiment, the first test loudspeaker 3a has the first front volume 14a and the first rear volume 17a. According to the present exemplary embodiment, the second test loudspeaker 3b has the second front volume 14b and the second rear volume 17b.

Since both test loudspeakers 3a, 3b are arranged one above the other, the first rear volume 17a of the first test loudspeaker 3a is arranged above the second front volume 14b of the second test loudspeaker 3b. At least the first rear volume 17a of the first test loudspeaker 3a and the second front volume 14b of the second test loudspeaker 3b are designed to be coaxial and / or congruent with one another.

Furthermore, the microphone 2 to be tested is not shown here. The test cavity 5 is shown here above the receiving area 7. The first front volume 14a of the first test loudspeaker 3a, the passage 15 of the receiving device 19 and / or the area above the receiving area 7 form the test cavity 5 here Test cavity 5 inserted and / or the test cavity 5 is formed as a result.

Furthermore, the housing 21 and the receiving device 19 are shown formed in one piece. Additionally or alternatively, the test device 1 can also use the Figure 1 and / or at least one of the following figures that Housing 21 and the receiving device 19 can be formed in one piece. The housing 21 can thus have the receiving device 19 or the receiving device 19 can have the housing 21.

Features that have already been described in the previous figure are not explained again for the sake of simplicity. Furthermore, features can only be described in the following figures. Furthermore, for the sake of simplicity, the same reference symbols are used for the same features. In addition, for the sake of clarity, not all features can be shown in the following figures. However, features shown in one or more of the preceding figures can also be present in one or more of the following figures. Furthermore, for the sake of clarity, features can also only be shown in one or more of the following figures. Nonetheless, features which are only shown in one or more of the following figures can also already be present in a previous figure.

Figure 3 shows a test device 1 for testing a plurality of microphones 2a-2i. The front three microphones 2a-2c are shown here in section. For a precise description of the test device 1, refer to Figure 1 and 2 referenced. The test device 1 shown here for testing a plurality of microphones 2a-2i is essentially a reproduction of the test devices from FIG Figure 1 and / or 2. The test device 1 thus has a plurality of receiving areas 7, only the three receiving areas 7a-7c being shown here. According to the present exemplary embodiment, at least one test loudspeaker 3 is arranged in the test device 1 for each microphone 2a-2i to be tested. As shown here, the test device 1 has a test loudspeaker 3 for each microphone 2a-2i to be tested. Additionally or alternatively, two or more test loudspeakers 3 can also be used for some microphones 2a-2i to be tested, as shown in FIG Figure 2 is shown to be assigned.

A reference microphone 8 is also assigned to each microphone 2a-2i to be tested.

With the test device 1 shown here, several microphones 2 can be tested at the same time.

The test device 1 is designed in such a way that the microphones 2a-2i to be tested are arranged next to one another, in particular flat.

Figure 4 shows a test device 1 for testing a microphone 2. For the sake of simplicity, not all features are provided here with a reference number. In addition, features that are already described in one or more of the previous figures are not explained again.

In this exemplary embodiment, the membrane 10 is made larger in comparison to the previous figures. This allows a higher sound pressure to be generated.

In particular, the at least one membrane 10 has an area 25 that is larger than a cross-sectional area 24 of the passage 15 in the axial direction X. The area 25 of the membrane 10 is parallel to the cross-sectional area 24. Additionally or alternatively, the area 25 of the membrane 10 can also be larger than the cross-sectional area 24 of the first detection volume 16. The area 25 is preferably the one-sided area of the membrane 10, since only the area 25 which faces the corresponding volume or the cavity acts to generate sound.

Additionally or alternatively, the area 25 of the membrane 10 can also be larger than the cross-sectional area 24 of the second acquisition volume 18.

Additionally or alternatively, the area 25 of the membrane 10 can also be larger than the cross-sectional area 24 of the front volume 14.

Additionally or alternatively, the area 25 of the membrane 10 can also be larger than the cross-sectional area 24 of the rear volume 17.

Additionally or alternatively, the area 25 of the membrane 10 can also be larger than the cross-sectional area 24 of the test cavity 5.

Additionally or alternatively, the area 25 of the membrane 10 can also be larger than the cross-sectional area 24 of the reference cavity 13.

For the sake of clarity, the cross-sectional area 24 is shown here only for the passage 15. Nevertheless, the cross-sectional area 24 is also defined for the other volumes / cavities 16, 18, 14, 17, 5, 13. In particular, the corresponding cross-sectional areas 24 are oriented parallel to the surface 25 of the membrane 10 or parallel to the membrane 10.

This has the advantage, explained by way of example on the basis of the passage 15, that the sound waves generated by the larger membrane 10 pass through a passage 15 with a smaller cross-section in order to reach the microphone 2 to be tested. This increases the sound pressure.

In the present exemplary embodiment, only one membrane 10 is shown. Furthermore, the test device 1 can also have a plurality of membranes 10, for example from a plurality of test loudspeakers 3. As a result, each membrane 10 can have an area 25 which is larger than the cross-sectional area 24 of the front volume 14, the passage 15, the rear volume 17, the test cavity 5, the reference cavity 13 of the first and / or the second acquisition volume 16, 18 in the axial direction X Alternatively, only the area 25 of at least one membrane 10 can be larger than the cross-sectional area 24 of the front volume 14, the passage 15, the rear volume 17, the test cavity 5, the reference cavity 13 of the first and / or the second acquisition volume 16, 18.

Furthermore, according to the present exemplary embodiment, the volume of the front volume 14 is greater than a volume of the passage 15 and / or of the first detection volume 16. As a result, the sound pressure that reaches the microphone 2 is increased.

In addition, according to the present exemplary embodiment, the volume of the rear volume 17 is greater than the volume of the second detection volume 18. This also increases the sound pressure.

Even if the test device 1 has several test loudspeakers 3, the corresponding volumes of the front volumes 14 and / or the corresponding rear volumes 17 can be greater than the volumes of the passage 15, the first acquisition volume 16 and the second acquisition volume 18, respectively.

According to Figure 4 If the passage 15, the first and the second acquisition volume 16, 18 are not arranged or oriented concentrically or not coaxially with the front volume 14, with the rear volume 17, with the test loudspeaker 3 and with the membrane 10, respectively. The passage 15, the first and the second acquisition volume 16, 18 are, as shown here, arranged offset in the transverse direction Y to the front volume 14 and the rear volume 17.

In an alternative embodiment, the passage 15, the first and / or the second acquisition volume 16, 18 can be arranged or oriented concentrically or coaxially with the front volume 14, with the rear volume 17, with the test loudspeaker 3 and / or with the membrane 10.

The present invention is not limited to the illustrated and described exemplary embodiments. Modifications within the scope of the claims are just as possible as a combination of the features, too if these are shown and described in different exemplary embodiments.

List of reference symbols

1

Test device

2

microphone

3

Test speaker

4th

Test tone

5

Test cavity

6th

first page

7th

Recording area

8th

Reference microphone

9

second page

10

membrane

11

first test tone portion

12th

second test tone component

13th

Reference cavity

14th

Front volume

15th

Passage

16

first acquisition volume

17th

Rear volume

18th

second acquisition volume

19th

Receiving facility

20th

Recess

21

casing

22nd

Top

23

bottom

24

Cross sectional area

25th

area

H

Lifting axis

X

Axial direction

Y

Transverse direction

Claims (15)

Test device (1) for testing a microphone (2) with at least one test loudspeaker (3) for generating at least one test tone (4),
with at least one test cavity (5) into which the test tone (4) can be emitted,
with at least one receiving area (7) for receiving the microphone (2) to be tested, which is designed such that the microphone (2) to be tested can be acoustically coupled to the test cavity (5), and
with at least one reference microphone (8) for determining a reference signal of the test tone (4) emitted by the test loudspeaker (3),
characterized,
that the test device (1) has a reference cavity (13) separate from the test cavity (5), into which the test tone (4) can also be emitted and to which the reference microphone (8) is acoustically coupled to determine the reference signal, and / or that the recording area (7) is arranged on a first side (6) of the test loudspeaker (3) and the reference microphone (8) is arranged on a second side (9) of the test loudspeaker (3) opposite the first side (6). Test device according to the preceding claim, characterized in that the test loudspeaker (3) is designed and / or arranged in such a way that it faces in the direction of its first side (6) and / or in the direction of the test cavity (5) and in the direction of its second side ( 9) and / or can emit the test tone (4) in the direction of the reference cavity (13), and / or
that the reference cavity (13) is arranged on the second side (9) of the test loudspeaker (3). Test device according to one or more of the preceding claims, characterized in that the test loudspeaker (3) comprises a membrane (10) by means of which the test tone (4) can be emitted into the test cavity (5) and / or into the reference cavity (13) , and
wherein the membrane (10) is preferably arranged between the test cavity (5) and the reference cavity (13) and / or wherein the membrane (10) preferably separates the test cavity (5) and the reference cavity (13) from one another. Test device according to one or more of the preceding claims, characterized in that the test device (1), in particular on the first side (6) of the test loudspeaker (3), has a recording device (19) for receiving the microphone (2) to be tested, which the receiving area (7), the receiving device (19) and / or the test device (1) preferably having a fixing device in order to be able to fix the microphone (2) to be tested, in particular non-positively and / or positively. Test device according to one or more of the preceding claims, characterized in that the test cavity (5) at least partially by means of a front volume (14) of the test loudspeaker (3), by means of a passage (15) of the receiving device (19) and / or the receiving area (7 ) and / or by means of a first acquisition volume (16) of the microphone (2) to be tested. Test device according to one or more of the preceding claims, characterized in that the reference cavity (13) at least partially by means of a rear volume (17) of the test loudspeaker (3) and / or a second detection volume (18) of the reference microphone (8) is formed. Test device according to one or more of the preceding claims, characterized in that the test cavity (5) and the reference cavity (13) are and / or are spaced from one another in an axial direction (X) of the test device (1)
that the at least one test loudspeaker (3) is arranged between the test cavity (5) and the reference cavity (13). Test device according to one or more of the preceding claims, characterized in that the front volume (14), the passage (15) of the receiving device (19) and / or the receiving area (7) and / or the first acquisition volume (16) is coaxial, in particular congruent , are arranged to one another and / or that the rear volume (17) and the second acquisition volume (18) are arranged coaxially, in particular congruently, to one another and / or
that the front volume (14), the passage (15), the rear volume (17), the first and / or the second acquisition volume (16, 18) have a round cross section. Test device according to one or more of the preceding claims, characterized in that the membrane (10) of the at least one test loudspeaker (3) is arranged and / or oriented in the transverse direction (Y)
that the membrane (10) has a larger area (25) than a cross-sectional area (24) of the front volume (14), the passage (15), the rear volume (17), the test cavity (5), the reference cavity (13) of the first and / or of the second acquisition volume (16, 18) in the axial direction (X). Test device according to one or more of the preceding claims, characterized in that a volume of the front volume (14) is greater than a volume of the passage (15) and / or of the first acquisition volume (16) and / or
that a volume of the rear volume (17) is greater than a volume of the second acquisition volume (18). Test device according to one or more of the preceding claims, characterized in that in the axial direction (X) of the test device (1) at least two test speakers (3) are arranged one above the other and / or that in the case of two test speakers (3) arranged one above the other, the rear volume (17) of the a test speaker (3) with the front volume (14) of the other test speaker (3) are arranged coaxially, in particular congruently, to one another. Test device according to one or more of the preceding claims, characterized in that the at least one test loudspeaker (3), the at least one reference microphone (8) and / or the at least one recording device (19) are arranged in a housing (21). Test device according to one or more of the preceding claims, characterized in that several microphones (2) can be tested by means of the test device (1) and / or that several microphones (2) can be recorded in the recording area (7), with several microphones (2) being able to be recorded for testing Microphones (2), the recording areas (7) are preferably arranged next to one another, in particular flat. Test device according to one or more of the preceding claims, characterized in that for testing a plurality of microphones (2) the test device (1) has a plurality of recording areas (7), a plurality of Test loudspeaker (3), several test cavities (5), several reference microphones (8) and / or several reference cavities (13). Test device according to one or more of the preceding claims, characterized in that the microphone (2) to be tested is and / or is a MEMS microphone
that the at least one test loudspeaker (3) is a MEMS loudspeaker and / or an electrodynamic loudspeaker and / or that the at least one reference microphone (8) is a MEMS microphone, an electrostatic microphone and / or condenser microphone.

Images