Audio / Signal Converter
By designing a sound/signal converter with a switching section, the problem of different minimum resonant frequencies of different musical instruments was solved, enabling signal output that can adapt to multiple frequencies in the same device and meet the sound recording needs of various musical instruments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-02-23
- Publication Date
- 2026-03-13
AI Technical Summary
In the recording of musical instrument sounds, different instruments have different lowest resonant frequencies that are best suited for recording, which means that multiple microphones are needed to meet the needs of different frequencies.
A sound/signal converter is designed, comprising a chamber having first and second openings, respectively blocked by first and second vibrating plates, generating signals through first and second converters, and selectively outputting signals using a switching unit to accommodate multiple lowest resonant frequencies.
It achieves the ability to adapt to multiple lowest resonant frequencies simultaneously in the same audio/signal converter, and can selectively output signals corresponding to different resonant modes to meet the sound recording needs of various musical instruments.
Smart Images
Figure CN115134725B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a sound / signal converter that converts sound propagating in a medium (e.g., air) such as a dynamic microphone into an electrical signal. Background Technology
[0002] As shown in Non-Patent Document 1, a loudspeaker that produces sound by vibrating a diaphragm based on an electrical signal has a minimum resonant frequency F0 that depends on the configuration of the vibration system supporting the diaphragm. The same applies to a microphone that converts the vibration of a diaphragm generated by receiving sound into an electrical signal.
[0003] Existing technical documents
[0004] Non-patent literature
[0005] Non-Patent Document 1: New Edition of the Encyclopedia of Loudspeakers and Speaker Boxes, supervised by Tamon Saeki, Seibundo Shinkosha, published May 28, 1999. Summary of the Invention
[0006] The technical problem that the invention aims to solve
[0007] However, in the recording of musical instrument sounds, the optimal lowest resonant frequency for recording varies depending on the type and purpose of the instrument being recorded. Therefore, when there are multiple instruments with different optimal lowest resonant frequencies, there is a need for multiple microphones suitable for recording them.
[0008] The present invention was made in view of the above description, and its object is to realize frequency characteristics corresponding to multiple types of lowest resonant frequencies F0 in a sound / signal converter.
[0009] Technical solutions for solving technical problems
[0010] The present invention provides a sound / signal converter comprising: a chamber having a first opening and a second opening; a first vibrating plate blocking the first opening; a second vibrating plate blocking the second opening; and a first converter that generates a first signal corresponding to the vibration of the first vibrating plate. Attached Figure Description
[0011] Figure 1 This is a cross-sectional view showing the configuration of a sound / signal converter according to an embodiment of the present invention.
[0012] Figure 2 This is a diagram illustrating the frequency characteristics of the audio / signal converter.
[0013] Explanation of reference numerals in the attached figures
[0014] 1…Sound / signal converter; 10…Cavity; 11, 12…Circular base plate; 21…First opening; 22…Second opening; 23, 24…Edge; 31…First vibrating plate; 32…Second vibrating plate; 41…First coil frame; 42…Second coil frame; 51…First coil; 52…Second coil; 61…First magnetic circuit; 62…Second magnetic circuit; 61G, 62G…Magnetic circuit gap; 611, 621…Inner magnetic yoke; 612, 622…Permanent magnet; 613, 623…Outer magnetic yoke; 70…Switching part; 71…First switch; 72…Second switch; a0, b0…Modible contact; a1~a3, b1~b3…Fixed contact; 80…Pin; 80a…Inner contact; 80b…Outer contact. Detailed Implementation
[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a cross-sectional view showing the configuration of a sound / signal converter 1 according to an embodiment of the present invention. Figure 1 The diagram shows the configuration of the sound / signal converter 1 by cutting a cross section using a plane containing an imaginary vibration axis passing through the center of the first vibrating plate 31 and the second vibrating plate 32.
[0016] exist Figure 1 In the middle, chamber 10 becomes a hollow cylindrical shape, in its axial direction ( Figure 1 The chamber has two circular base plates 11 and 12 of the same size at both ends (in the left and right directions). Each of the two circular base plates 11 and 12 has a first circular opening 21 and a second circular opening 22 of the same size. The center of the first opening 21 is located at the same position as the center of the circular base plate 11, and the center of the second opening 22 is located at the same position as the center of the circular base plate 12. It should be noted that the shape of the chamber can be a cuboid or a sphere, etc.
[0017] The first vibrating plate 31 is hemispherical with an annular rim 23 around it, blocking the first opening 21. The rim 23 functions as a hanger supporting the first vibrating plate on the inner periphery of the first opening 21. Similarly, the second vibrating plate 32 is hemispherical with an annular rim 24 around it, blocking the second opening. The rim 24 functions as a hanger supporting the second vibrating plate on the inner periphery of the second opening 22. The first vibrating plate 31 and the second vibrating plate 32 have the same area and weight. It should be noted that the shape of the vibrating plate can be planar or conical.
[0018] A hollow cylindrical first coil frame 41 protruding inward into the cavity 10 is provided in the area surrounding the first vibrating plate 31. A first coil 51 is wound around this first coil frame 41. The first coil 51 is disposed in the magnetic circuit gap 61G of the first magnetic circuit 61 formed by the inner magnetic yoke 611, the permanent magnet 612, and the outer magnetic yoke 613. The first coil 51 functions as a first transducer that generates a first signal v1 in response to the vibration of the first vibrating plate 31.
[0019] Similarly, a hollow cylindrical second coil holder 42 protruding inward into the chamber 10 is provided around the second vibrating plate 32. A second coil 52 is wound around this second coil holder 42. This second coil 52 is positioned within the magnetic circuit gap 62G of the second magnetic circuit 62, which is formed by the same inner magnetic yoke 621, permanent magnet 622, and outer magnetic yoke 623 as the first magnetic circuit 61. The second coil 52 functions as a second transducer that generates a second signal v2 corresponding to the vibration of the second vibrating plate 32. The first magnetic circuit 61 and the second magnetic circuit 62 are fixed within the chamber 10.
[0020] The switching unit 70 includes: a first switch 71, which consists of a movable contact a0 and fixed contacts a1 to a3 that can contact the movable contact a0; and a second switch 72, which consists of a movable contact b0 and fixed contacts b1 to b3 that can contact the movable contact b0. The first switch 71 and the second switch 72 are switches that link the movable contact a0 and the movable contact b0. When the movable contact a0 is in contact with the fixed contacts a1 to a3 respectively, the movable contact b0 is in contact with the fixed contacts b1 to b3 respectively. The switching unit 70 is a component that selects either a first signal v1 from the first coil 51 or a second signal v2 from the second coil 52 to generate an electrical signal output between the inner contact 80a and the outer contact 80b of the latch 80.
[0021] exist Figure 1In this design, "+" and "-" are marked on the two wires connected to the two ends of the first coil 51 and the two wires connected to the two ends of the second coil 52. These "+" and "-" indicate the polarity of the first signal v1 generated by the first coil 51 and the second signal v2 generated by the second coil 52 when the first coil 51 moves towards the second vibrating plate 32 and the second coil 52 moves towards the first vibrating plate 31 (i.e., in the opposite direction of movement to the first coil 51). That is, when the first coil 51 moves towards the second vibrating plate 32 and the second coil 52 moves towards the first vibrating plate 31, the first coil 51 and the second coil 52 function as voltage sources, with the end connected to the wire marked "+" as the positive terminal and the end connected to the wire marked "-" as the negative terminal, respectively generating the first signal v1 and the second signal v2. Hereinafter, for ease of explanation, the side of each end of the first coil 51 and the second coil 52 connected to the wire marked "+" will be considered the positive terminal, and the side connected to the wire marked "-" will be considered the negative terminal.
[0022] The positive terminal of the first coil 51 is connected to the movable contact a0 and the fixed contact b3. The negative terminal of the first coil 51 is connected to the outer contact 80b of the pin 80. The positive terminal of the second coil 52 is connected to the fixed contacts a2 and b1. The negative terminal of the second coil 52 is connected to the fixed contacts a1 and b2.
[0023] Here, when the movable contact a0 is in contact with the fixed contact a1 and the movable contact b0 is in contact with the fixed contact b1, the inner contact 80a of the latch 80 reaches the outer contact 80b of the latch 80 via the following path: movable contact b0 → fixed contact b1 → positive terminal of the second coil 52 → negative terminal of the second coil 52 → fixed contact a1 → movable contact a0 → positive terminal of the first coil 51 → negative terminal of the first coil 51. In this case, the switching unit 70 functions as an adder that adds the first signal v1 and the second signal v2 with the same polarity and outputs the total level of the first signal v1 and the second signal v2 between the inner contact 80a and the outer contact 80b of the latch 80.
[0024] Furthermore, when movable contact a0 is in contact with fixed contact a2 and movable contact b0 is in contact with fixed contact b2, the inner contact 80a of the latch 80 reaches the outer contact 80b of the latch 80 via the following path: movable contact b0 → fixed contact b2 → negative terminal of the second coil 52 → positive terminal of the second coil 52 → fixed contact a2 → movable contact a0 → positive terminal of the first coil 51 → negative terminal of the first coil 51. In this case, the switching unit 70 functions as a subtractor that subtracts the second signal v2 from the first signal v1, that is, it adds the first signal v1 and the second signal v2 with opposite polarities and outputs the level difference between the first signal v1 and the second signal v2 to the inner contact 80a and the outer contact 80b of the latch 80.
[0025] Furthermore, when the movable contact a0 is in contact with the fixed contact a3 and the movable contact b0 is in contact with the fixed contact b3, the inner contact 80a of the latch 80 reaches the outer contact 80b of the latch 80 via the path of movable contact b0 → fixed contact b3 → positive terminal of the first coil 51 → negative terminal of the first coil 51. In this case, the first signal v1 is output between the inner contact 80a and the outer contact 80b of the latch 80.
[0026] Next, the operation of this embodiment will be explained. Figure 1 In this diagram, S1 is the sound acting on the first vibrating plate 31, and S2 is the sound acting on the second vibrating plate 32. Sounds S1 and S2 each contain in-phase components, which generate a first resonance mode within the chamber 10, causing the first vibrating plate 31 and the second vibrating plate 32 to move in the same direction. Here, "moving in the same direction" means that the relative movement of the first vibrating plate 31 relative to the magnetic circuit gap 61G is in the same direction as the relative movement of the second vibrating plate 32 relative to the magnetic circuit gap 62G. It should be noted that, in the following description of the first resonance mode, to avoid complexity, the in-phase component contained in sound S1 will be simply referred to as sound S1, and the in-phase component contained in sound S2 will be simply referred to as sound S2.
[0027] In this first resonance mode, as the pressure of the air compression / reduction wave, i.e., sound S1, increases and the first vibrating plate 31 moves in the direction of pressing air into the chamber, the pressure of sound S2 also increases simultaneously, and the second vibrating plate 32 also moves in the direction of pressing air into the chamber. Therefore, the air inside the chamber 10 is strongly compressed due to the first vibrating plate 31 and the second vibrating plate 32.
[0028] As the pressure of sound S1 decreases and the first vibrating plate 31 moves in the direction of drawing air out of the chamber 10, the pressure of sound S2 also decreases simultaneously, and the second vibrating plate 32 also moves in the direction of drawing air out of the chamber 10. Therefore, the air inside the chamber 10 expands violently due to the first vibrating plate 31 and the second vibrating plate 32.
[0029] Thus, in the first resonance mode, the air inside chamber 10 acts as an air spring, further strengthening its effect, resulting in a further increase in the lowest resonance frequency F0. Since the first vibrating plate 31 and the second vibrating plate 32 vibrate in the same direction, a first signal v1 and a second signal v2, which are in phase with each other, are output from the first coil 51 and the second coil 52.
[0030] In contrast, the second resonance mode is generated by the difference between sound S1 and sound S2, with the first vibrating plate 31 and the second vibrating plate 32 moving in opposite directions. Here, "moving in opposite directions" means that the relative movement of the first vibrating plate 31 with respect to the magnetic circuit gap 61G and the relative movement of the second vibrating plate 32 with respect to the magnetic circuit gap 62G are opposite. If the pressure of sound S1 increases and the pressure of sound S2 further increases, the first vibrating plate 31 moves in the direction of expelling air from the chamber, and the second vibrating plate 32 moves in the direction of extracting air from the chamber.
[0031] Subsequently, if the pressure of sound S2 increases and the pressure of sound S1 further increases, the second vibrating plate 32 moves in the direction of pressing air into the chamber, and the first vibrating plate 31 moves in the direction of extracting air from the chamber. In this way, since the first and second vibrating plates move in opposite directions, the air in the chamber does not act as an air spring, but rather acts as the added mass of the two vibrating plates.
[0032] Thus, in the second resonance mode, the air inside chamber 10 acts as a load mass, resulting in a further reduction in the lowest resonant frequency F0. Since the first vibrating plate 31 and the second vibrating plate 32 vibrate in opposite directions, a first signal v1 and a second signal v2, which are out of phase with each other, are output from the first coil 51 and the second coil 52.
[0033] exist Figure 1 In the sound / signal converter 1, if a low-frequency sound source such as a bass drum (not shown) is positioned on the front of the first diaphragm (left side of the figure) (first configuration of sound source and sound / signal converter), a strong sound S1 emitted from the sound source reaches the first diaphragm 31, while a weaker sound S2, which is almost in phase with the sound S1 (due to the smaller distance between the first and second diaphragms compared to the wavelength of the sound), reaches the second diaphragm 32. As a result, both the first and second resonance modes are generated simultaneously. In this case, the first signal v1 generated by the first coil 51 and the second signal v2 generated by the second coil 52 respectively contain signals corresponding to the vibrations of the first resonance mode and the vibrations of the second resonance mode.
[0034] Therefore, by using the switching unit 70 to select either the first signal v1 or the second signal v2, a signal containing a vibration corresponding to the first resonance mode and a signal corresponding to the vibration of the second resonance mode can be obtained from the sound / signal converter 1. Furthermore, by using the switching unit 70 to add the first signal v1 and the second signal v2 with the same polarity, a signal representing the vibration of the first resonance mode (fourth signal) can be obtained, and by adding the first signal v1 and the second signal v2 with opposite polarities (third signal) can be obtained.
[0035] The inventors of this application simulated the frequency characteristics of various signals that can be obtained in the sound / signal converter 1 when the sound from the sound source arrives from the direction of the first vibrating plate 31. Figure 2 This is a graph representing the frequency characteristics of these signals. In Figure 2 In the diagram, the horizontal axis represents frequency, and the vertical axis represents the various signal levels that can be obtained from the audio / signal converter 1.
[0036] exist Figure 2 In this embodiment, the frequency characteristic P(v1) is the frequency characteristic of the first signal v1. This frequency characteristic P(v1) is a bimodal characteristic with peaks around 60Hz and 85Hz. Here, the peak around 60Hz corresponds to the lowest resonant frequency F0 of the second resonant mode, and the peak around 85Hz corresponds to the lowest resonant frequency F0 of the first resonant mode. Thus, according to this embodiment, a first signal v1 containing a signal corresponding to the vibration of the first resonant mode and a signal corresponding to the vibration of the second resonant mode can be obtained from the first coil 31. This first signal v1 is output to the latch 80 by contacting the movable contacts a0 and b0 with the fixed contacts a3 and b3.
[0037] It should be noted that by changing the relative position of the sound source... Figure 1 The configuration of the sound / signal converter allows for adjustment of the components of the first signal v1. For example, if the distance from the sound source to the first diaphragm and the distance from the sound source to the second diaphragm are the same (a second configuration of the sound source and the sound / signal converter), then because the sounds S1 and S2 reaching the two diaphragms have more in-phase components and less differential components, the two diaphragms mainly vibrate in the first mode, and the first resonance mode component of the first signal v1 increases. By adjusting the configuration of the sound / signal converter relative to the sound source to between the first and second configurations, the ratio of the first resonance mode component and the second resonance mode component contained in the first signal v1 can be changed.
[0038] Furthermore, if a baffle or similar device is used to block the sound S2 from the sound source to the second diaphragm, and the arrangement is such that only the sound S1 emitted from the sound source reaches the first diaphragm, then the difference between the sounds S1 and S2 reaching the two diaphragms increases while the in-phase component decreases. As a result, the two diaphragms vibrate primarily in the second mode, resulting in a first signal v1 with a higher proportion of the second resonance mode component. By changing the degree of blocking by the baffle, the ratio of the first resonance mode component to the second resonance mode component contained in the first signal v1 can be changed.
[0039] The frequency characteristic P(v2) is the frequency characteristic of the second signal v2. This frequency characteristic P(v2), like the frequency characteristic P(v1), is a bimodal frequency characteristic with peaks around 60Hz and 85Hz. Thus, a second signal v2 containing signals corresponding to the vibrations of the first resonant mode and the vibrations of the second resonant mode can be obtained from the second coil 32. This second signal v2 can be output to the plug 80.
[0040] The frequency response P(v1-v2) is the frequency response of the first signal v1 minus the second signal v2, that is, the signal (v1-v2) added together with opposite polarities. This frequency response P(v1-v2) is a single-peak frequency response with a peak at the lowest resonant frequency F0 (around 60Hz) of the second resonant mode.
[0041] Thus, both the first signal v1 and the second signal v2 contain a signal corresponding to the vibration of the first resonance mode and a signal corresponding to the vibration of the second resonance mode. The signals in the first signal v1 and the second signal v2 corresponding to the first resonance mode are in phase with each other. Furthermore, the signals in the first signal v1 and the second signal v2 corresponding to the second resonance mode are out of phase with each other. Therefore, if the first signal v1 and the second signal are added with opposite polarities, the signals in the first signal v1 and the second signal v2 corresponding to the vibration of the first resonance mode cancel each other out, emphasizing the second resonance mode, and a third signal corresponding to the vibration of the second resonance mode can be obtained. This signal corresponding to the vibration of the second resonance mode is output to the latch 80 by bringing the movable contacts a0 and b0 into contact with the fixed contacts a2 and b2.
[0042] The frequency response P(v1+v2) is the frequency response of the signal (v1+v2) resulting from the addition of the first signal v1 and the second signal v2 with the same polarity. This frequency response P(v1+v2) is a single-peaked frequency response with a peak at the lowest resonant frequency F0 (around 85Hz) of the first resonant mode.
[0043] If the first signal v1 and the second signal v2 are added with the same polarity, the signals in the first signal v1 corresponding to the vibration of the second resonance mode and the signals in the second signal v2 corresponding to the vibration of the second resonance mode cancel each other out, emphasizing the first resonance mode, and a fourth signal corresponding to the vibration of the first resonance mode can be obtained. This fourth signal corresponding to the vibration of the first resonance mode is output to the latch 80 by bringing the movable contacts a0 and b0 into contact with the fixed contacts a1 and b1.
[0044] Thus, according to this embodiment, a signal with frequency characteristics having two lowest resonant frequencies can be obtained in the audio / signal converter 1. Furthermore, according to this embodiment, the signal of either of the two lowest resonant frequencies F0 of the audio / signal converter 1 can be selectively obtained through the switching operation of the switching unit 70.
[0045] <Other Implementation Methods>
[0046] The embodiments of the present invention have been described above, and other embodiments of the present invention can also be conceived. For example, as described below.
[0047] (1) In the above embodiment, although the first vibration plate 31 and the second vibration plate 32 are respectively arranged on the circular base plate 11 and the circular base plate 12 located on opposite sides in the chamber 10, the first vibration plate 31 and the second vibration plate 32 can also be arranged on the same base plate.
[0048] (2) In the above embodiment, the first coil 51, the magnetic circuit 61, the second coil 52 and the magnetic circuit 62 are disposed inside the cavity 10, but they can also be disposed outside the cavity 10.
[0049] (3) In the above embodiment, the switching unit 70 can be omitted, and the first signal v1 from the first coil 51 and the second signal v2 from the second coil 52 can be output to different pins respectively. In this case, the external mixer of the audio / signal converter 1 can selectively add the first signal v1 and the second signal v2 with the same polarity, or add them with opposite polarities, and output the result (fourth signal or third signal), or only perform one of these two additions, according to the user's instructions.
[0050] (4) In the above embodiments, the present invention is applicable to moving-coil microphones with movable coils. However, the scope of the present invention is not limited to such moving-coil microphones. The present invention is also applicable to variable-capacitance microphones where the capacitance value changes according to the vibration of the diaphragm to obtain an electrical signal.
Claims
1. A voice / signal converter, characterized in that, have: A chamber having a first opening and a second opening; A first vibrating plate blocks the first opening; The second vibrating plate blocks the second opening; A first converter generates a first signal in response to the vibration of the first vibrating plate; The second converter generates a second signal in response to the vibration of the second vibrating plate; The first converter and the second converter are configured in the same chamber, each having its own magnetic circuit, and generate the first signal and the second signal independently of each other.
2. The audio / signal converter according to claim 1, wherein, The vibration of the first vibrating plate and the second vibrating plate includes a first resonance mode in which the first vibrating plate and the second vibrating plate move in the same direction relative to each other, and a second resonance mode in which the first vibrating plate and the second vibrating plate move in opposite directions relative to each other.
3. The audio / signal converter according to claim 2, wherein, It further includes a subtractor that generates a third signal corresponding to the vibration of the second resonance mode by subtracting one of the first signal and the second signal from the other.
4. The audio / signal converter according to claim 2, wherein, It further includes an adder that generates a fourth signal corresponding to the vibration of the first resonance mode by adding the first signal and the second signal.
5. The audio / signal converter according to any one of claims 1 to 4, wherein, The first and second vibrating plates have the same area and weight.
Citation Information
Patent Citations
Dual diaphragm microphone
CN107431866A
Electro-acoustic transducer with two diaphragms
US20030048920A1