CN210491178U

CN210491178U - Phase plug for sound reinforcement

Info

Publication number: CN210491178U
Application number: CN201921650111.1U
Authority: CN
Inventors: 张祥奎
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-05-08
Anticipated expiration: 2029-09-30

Abstract

The phase plug for sound reinforcement comprises more than two annular sound wave channels, the cross sections of the sound wave channels are exponential-type cross sections, the area ratio of an input port to an output port of each sound wave channel is the same, equal transmission ratio characteristics are formed, and the simulated sound paths of sound waves in the sound wave channels are equal, so that equal phase characteristics are formed. By adopting the technical scheme, the exponential-type section sound wave channel is adopted, the distortion in the sound wave transmission process is reduced, the equal transmission ratio characteristic is realized, the sound wave passes through each sound wave channel of the phase plug, the equivalent wave front with the same transmission efficiency is formed at the outlet, the equal phase characteristic is realized, and the coupling superposition of the sound wave full effect output by the sound wave channel is realized. In addition, the utility model discloses still disclose the manufacturing method of this phase place stopper.

Description

Phase plug for sound reinforcement

Technical Field

The utility model belongs to the technical field of public address equipment and specifically relates to a phase place stopper for public address.

Background

In professional public address applications, a horn structure (see fig.) is generally employed in order to raise the sound pressure level SPL (acoustic unit of volume). The bugle can make the radiation resistance of the load before the driver increase to show the efficiency that improves the public address, make the sound pressure level promote by a wide margin. However, at the same time, acoustic interference often occurs, which causes a distortion effect and significantly reduces the sound quality of the sound reinforcement.

To solve this problem, a phase plug structure is often used to reduce acoustic interference in the horn and improve the sound quality.

From the known theory of correlation of horn speakers, we can sum the horn speaker design techniques as: a center, three cardinal points.

One center-reduced distortion ratio (THD). Because distortion directly destroys the sound quality of sound amplification and affects the sound amplification effect.

Three basic points can also be understood as three directions of the optimization design. As shown in figure 1 of the drawings, in which,

1. sound amplification efficiency-the horn dependent compression ratio, is usually expressed as the diaphragm to throat area ratio: s diaphragm/S throat

2. Lower cut-off frequency f_{Lower part}——f_{Lower part}Mainly depending on the length (L) of the horn. However, too long a length L increases the distortion THD. And results in oversized profiles and difficult transportation. Thus f_{Lower part}Has limited optimizable space.

3. Effective playback upper limit frequency f_{On the upper part}——f_{Lower part}～f_{On the upper part}Constituting the effective operating bandwidth of the horn speaker. f. of_{On the upper part}Depending on the structure of the phase plug. f. of_{On the upper part}The higher the effective operating bandwidth. Thus, f_{On the upper part}Will be the main attack direction for the horn optimization design.

The existing phase plug has the following problems:

first, the phase plug is of an external pressure type, which can improve the intermediate frequency interference, but cannot solve the problem of high frequency extension of the intermediate frequency driver, so that the horn intermediate frequency bandwidth is narrow and the available frequency range is limited. The frequency range is typically 300Hz-1.5 kHz; generally, when a front cavity under a dust cap vibrates up and down on a medium-frequency vibrating diaphragm, air in a front cavity area of the front cavity is compressed and released to form an air cushion effect, so that the vibration characteristic of the vibrating diaphragm is influenced, nonlinear vibration is formed, and nonlinear distortion is caused; generally, in the sound amplification application, a higher sound pressure level is required to make sound transmission more distant and enlarge the sound amplification coverage, which leads to an increase in input power and thus the power borne by the intermediate frequency unit. This will cause the voice coil temperature to increase rapidly, which, if not effectively dissipated, will cause the voice coil to overheat "burn out".

Secondly, the sound wave channel adopts a parallel pipe type, a linear type, a parabolic type and the like, and the transmission distortion is high.

Thirdly, the ratio of the input port area to the output port area of each acoustic channel is different, so that equivalent power transmission of each channel cannot be realized.

Fourthly, the transmission time of the sound waves in each sound wave channel is different, namely two or more sound waves cannot be triggered and arrive at the same time, the full-effect coupling superposition of the sound waves cannot be realized, and local interference or cancellation is formed due to phase difference.

In view of the foregoing, improvements are needed.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a phase place stopper for amplifying sound that can effectively solve above-mentioned problem. In order to achieve the above purpose, the utility model adopts the following technical scheme:

the phase plug for sound reinforcement comprises more than two annular sound wave channels, the cross sections of the sound wave channels are exponential-type cross sections, the area ratio of an input port to an output port of each sound wave channel is the same, and the phases of sound waves in the sound wave channels are equal.

By adopting the technical scheme, the section of the sound wave channel is an index-type section, the sound waves are transmitted and diffused along the index-type pipeline, and compared with a parallel pipe, a linear type, a parabolic type and the like, the transmission distortion is lowest. The equal transmission ratio characteristics are formed by the same area ratio of the input port and the output port of each sound wave channel, so that the equivalent wave front with the same transmission efficiency is formed at the outlet after sound waves pass through each sound wave channel of the phase plug. The phases of the sound waves in the sound wave channels are equal, that is, the analog sound paths are equal, because the sound velocity is a constant, and if the phases are equal, that is, the analog sound paths are equal, the sound wave transmission time is equal, that is, the phases are equal, which is equivalent to a synchronization effect. I.e. two or more sound waves are triggered at the same time, arriving at the same time. Ideally, the equiphase is a necessary condition for constituting the acoustic wave total-efficiency coupling. Namely: only sound waves with the same phase characteristics can realize full-effect coupling superposition, otherwise, local interference or cancellation can be formed due to phase difference.

Further, the section of the sound wave channel comprises a section line q close to the center of the phase plug_iAnd an exponential cross-sectional curve y near the outside of the phase plug_iAnd i refers to the ith acoustic channel from the center of the phase plug to the outer side.

Further, an exponential cross-sectional curve y_iIs expressed as y_i=a^xWherein a is a constant and greater than 1. Each acoustic channel must follow the same y = a^xTo ensure that the acoustic transmission characteristics of each channel are consistent. This will effectively reduce the coupling distortion of the acoustic waves at the exit of each acoustic channel.

Further, the analog acoustic path d of the acoustic wave in the acoustic channel_i=q_i+c_iThe input end of the phase plug is a conical curved surface, and the section curve of the conical curved surface in the sound wave channel is c, E_iIs q_iPoint of intersection with c, c_iIs E_iAnd E₁The path length of the two points on the cross-sectional curve c. The analog sound path of the sound wave in each sound wave channel is given, and because the sound propagation speed is constant, the equal phase of the sound wave can be realized only by the equal distance of the analog sound path in each sound wave channel.

Further, E₁Is the simulated sound source point of the diaphragm. The driver is used as a sound source, and the theoretical sound source point of the driver is located at the physical central point of the voice coil. The input end of the phase plug is provided with a conical curved surface which is matched with a vibration diaphragm of the driver, and a voice coil and a bone thereof are assumedThe frame is a rigid body, then E₁Namely the analog sound source point of the diaphragm.

Further, S_i/s_i=b，S_iIs the output port area, s, of the ith acoustic channel_iB is a constant value, which is the input port area of the ith acoustic channel. If 3 sound wave channels are arranged, according to the principle of equal transmission ratio, the area ratio of the input port to the output port of the three sound wave channels is the same, then the transmission ratio of the 3 channels is equal, and S is₁/s₁= S₂/s₂= S₃/s₃。

Furthermore, the phase plug comprises an input end with a conical curved surface and an implant body arranged in the middle of the input end, the outer diameter of the implant body is matched with the inner diameter of the intermediate frequency driver, the phase plug is implanted into the intermediate frequency driver through the implant body, and the conical curved surface is matched with a vibrating diaphragm of the intermediate frequency driver.

The embedded design has the advantages that firstly, the conical whole-membrane driver with the high-frequency sound-producing area concentrated at the central part can obtain more high-frequency responses and effectively expand the upper limit f of the frequency through the embedded structural design_{On the upper part}Thereby increasing the effective operating bandwidth of the horn. Second, the piston compliance of the diaphragm can be optimized. Avoids the nonlinear distortion caused by the external pressure type and the air cushion effect in the convex cap. Thirdly, the implantation enables the voice coil to communicate with the outside by forming an annular channel with the implantation portion. In operation, through piston vibration, form convection type heat dissipation. The heat loss and overheating damage caused by temperature rise can be effectively reduced. The working efficiency and the reliability of the system are improved.

Drawings

FIG. 1 is a graph of SPL-f.

Fig. 2 is a perspective view of a phase plug.

Fig. 3 is a schematic diagram of the assembly of the phase plug and the intermediate frequency driver.

Fig. 4 is a schematic diagram of the acoustic channel input port at the input of the phase plug.

Fig. 5 is a schematic view of the acoustic channel output at the output of the phase plug.

Fig. 6 is a schematic diagram of a loudspeaker.

Fig. 7 is a schematic diagram of a phase plug manufacturing process.

Fig. 8 is a top plan view of fig. 7.

Fig. 9 is a schematic illustration of a phase plug manufacturing process installation master.

In fig. 10, y = a^xA coordinate model diagram of the exponential model of (1).

Fig. 11 is a table of phase response curves for each acoustic channel.

Fig. 12 is a direction test table of the present phase plug.

Fig. 13 is an efficiency test table of the present phase plug.

Fig. 14 is a distortion test table of the present phase plug.

Detailed Description

The present invention will be described with reference to the following embodiments.

As shown in fig. 2 and 3, a phase plug 1 for sound reinforcement includes more than two annular sound wave channels, specifically, in this embodiment, the phase plug 1 is provided with three annular sound wave channels, and the sound wave channels K are respectively arranged from the center to the periphery₁Acoustic wave channel K₂And an acoustic channel K₃。

In the three acoustic channels, the cross section of the acoustic channel is an exponential cross section, the constants a of the exponential functions of the acoustic channels are equal (called as the same exponential model), the ratio of the areas of the input port and the output port of each acoustic channel is the same (called as the equal transmission ratio), and the simulated acoustic paths of the acoustic waves in the acoustic channels are equal (called as the equal phase).

Aiming at the characteristics of the same exponential model, the sound wave channels are designed as follows:

as shown in fig. 3, 4, 5, 10, the cross-section of the acoustic channel comprises a cross-section line q near the center of the phase plug 1_iAnd an exponential cross-sectional curve y near the outside of the phase plug 1_iAnd i refers to the i-th acoustic channel from the center to the outer side of the phase plug 1. Exponential cross-sectional curve y_iIs expressed as y_i=a^xWherein a is a constant and greater than 1. Each acoustic channel, consisting of L/L, must follow the same y = a^xIndex of (1)Models, i.e. acoustic channels K₁Acoustic wave channel K₂And an acoustic channel K₃A in (b) is the same value to ensure that the acoustic transmission characteristics of each channel are consistent. This will effectively reduce the coupling distortion of the acoustic waves at the exit of each acoustic channel.

For the characteristics of equal phase (or equal sound path), the following design is adopted for each sound wave channel:

as shown in fig. 3, the analog acoustic path d of the acoustic channel_i=q_i+c_iWherein, the input end of the phase plug 1 is a conical curved surface, and the section curve of the conical curved surface in the sound wave channel is c, E_iIs q_iPoint of intersection with c, c_iIs E_iAnd E₁The path length of the two points on the cross-sectional curve c. To the three acoustic channels of the present embodiment, E₁As a point of simulated sound source of the diaphragm 5, E₀As a theoretical sound source point of the diaphragm 5, an analog sound path d₁Is curve E₁O₁Analog acoustic path d₂Is curve E₁E₂+E₂O₂Analog acoustic path d₃Is curve E₁E₃+E₃O₃Thus, d₁= d₂= d₃And E₁O₁= E₁E₂+E₂O₂= E₁E₃+E₃O₃。

The analog sound path of the sound wave in each sound wave channel is given, and because the sound propagation speed is constant, the equal phase of the sound wave can be realized only by the equal distance of the analog sound path in each sound wave channel. E₁Is the simulated sound source point of the diaphragm 5. The driver is used as a sound source, and the theoretical sound source point of the driver is located at the physical central point of the voice coil. The input end of the phase plug 1 is provided with a conical curved surface which is matched with a vibrating diaphragm 5 of the driver, and if a voice coil and a framework thereof are rigid bodies, E₁I.e. the simulated sound source point of the diaphragm 5.

Aiming at the characteristics of equal transmission ratio, each sound wave channel adopts the following design:

as shown in FIGS. 3-5, S_i/s_i=b，S_iIs the output port area, s, of the ith acoustic channel_iB is a constant value, which is the input port area of the ith acoustic channel. If 3 sound wave channels are arranged, according to the principle of equal transmission ratio, the area ratio of the input port to the output port of the three sound wave channels is the same, then the transmission ratio of the 3 channels is equal, and S is₁/s₁= S₂/s₂= S₃/s₃。

In addition, as shown in fig. 1 and 2, as a preferred scheme, the phase plug 1 adopts an implanted structural design and is implanted into the intermediate frequency driver 2, specifically, the phase plug 1 includes an input end with a conical curved surface and an implant 3 arranged at a middle position of the input end, an outer diameter of the implant 3 matches with an inner diameter of the intermediate frequency driver 2, the phase plug 1 is implanted into the intermediate frequency driver 2 through the implant 3, and the conical curved surface matches with a diaphragm 5 of the intermediate frequency driver 2.

In addition, in order to manufacture the phase plug 1 satisfying the above characteristics, the present invention provides a method for designing and manufacturing the phase plug 1 for sound amplification, which comprises the following steps:

s1: determining relevant parameters according to the technical requirements and design targets of the horn loudspeaker;

s1-1: target operating bandwidth f of horn speaker in combination with reference to frequency response range of driver_{Lower part}~f_{On the upper part}Determining the length range of the horn;

s1-2: the sensitivity and the power of the driver are referenced, and the range of the compression ratio can be calculated by combining the target maximum sound pressure level;

s1-3: from the compression ratio = diaphragm 5 area/throat area, the diameter of the phase plug 1 outlet (i.e. throat) can be calculated;

s2: according to the equivalent acoustic path simulation algorithm, the computer CAD auxiliary drawing software is used for meeting and waiting for the simulation acoustic path (E)₁O₁= E₁E₂+E₂O₂= E₁E₃+E₃O₃) Equal transmission ratio (S)₁/s₁= S₂/s₂= S₃/s₃) And the same indexModel (y)_i=a^xAnd the values of a are the same), the structural model and the relevant size of the phase plug 1 can be determined. And then, by means of acoustic test software, the structure of the phase plug is assisted to be finely adjusted and corrected through actually testing the phase response curves of the

channels

1, 2 and 3. Finally, the phase curves of the 3 channels are overlapped, and the phase curves are overlapped to indicate that the phases are equal, so that the effective sound paths of the 3 channels are equal. At the outlet, the total-effect coupling of the sound waves of all channels is superposed to form a constant-phase wave front with consistent characteristics. Theoretically, the equal phase wave front can make the directivity control of the horn uniform and consistent, and the distortion caused by interference is the lowest. FIG. 11 is a table of phase response curves for each acoustic channel, where K is the

number

1, 2, and 3₁、K₂、K₃Phase response curve of channel single conduction, 1+2+3 is K₁、K₂、K₃The phase response curve of the channels conducting simultaneously can be known from the table. The 4 lines are substantially coincident, indicating equal phase for each channel.

S3: manufacturing a phase plug 1 model by a 3D printing technology, matching a driver, and measuring the phase response of each channel by an obstacle plate test method by means of acoustic test software, and finally enabling the phase curves of the channels to be approximately overlapped by repeatedly correcting the deviation value of the related dimension so as to finally determine the accurate dimension and structure of the phase plug 1;

s4: as shown in fig. 6, the corresponding horn is assembled, the test-related parameter is compared with the design target parameter, and the gap between the diaphragm 5 and the phase plug 1 is adjusted by the annular spacer 6 to increase f_{On the upper part}Adjusting the length L of the horn_hTo extend f_{Lower part}Let f be_{On the upper part}～f_{Lower part}The design target is achieved;

s5: manufacturing a split mold of each part by using a numerical control machining center, and producing a finished product;

s6: as shown in fig. 7-9, an assembly master 9 having the same curvature as the diaphragm 5 is manufactured by a numerical control machining center in a profiling manner;

s7: and assembling, gluing each positioning platform 4, inserting the positioning wing plates 7 into the corresponding positioning grooves 8, positioning by using an assembling explorator 9, pressurizing until the wing plates reach the positioning platforms 4, and taking down the assembling explorator 9 after the glue is cured.

By adopting the technical scheme, the three sound wave channels adopt the same index model, compared with a parallel tube model, a linear model, a parabolic model and the like, the transmission distortion is lowest, and the a values in the index models are the same, so that the sound wave transmission characteristics of each channel are consistent. This will effectively reduce the coupling distortion of the acoustic waves at the exit of each acoustic channel.

The three sound wave channels have equal transmission ratios, which enables the sound wave to form an equivalent wave front with the same transmission efficiency at the outlet after passing through each sound wave channel of the phase plug 1.

The three sound wave channels are in equal phase (equal sound paths), and the equal phase is equivalent to a synchronous effect, namely two or more sound waves are triggered and arrive at the same time, because the sound velocity is a constant, the equal phase is realized, namely the analog sound paths are equal, the equal sound wave transmission time is realized, and theoretically, the equal phase is a necessary condition for forming sound wave full-effect coupling. Namely: only sound waves with the same phase characteristics can realize full-effect coupling superposition, otherwise, local interference or cancellation can be formed due to phase difference.

The embedded design has the advantages that firstly, the conical whole-membrane driver with the high-frequency sound-producing area concentrated at the central part can obtain more high-frequency responses and effectively expand the upper limit f of the frequency through the embedded structural design_{On the upper part}Thereby increasing the effective operating bandwidth of the horn. Second, the piston vibration compliance of the diaphragm 5 can be optimized. Avoids the nonlinear distortion caused by the external pressure type and the air cushion effect in the convex cap. Thirdly, the implantation enables the voice coil to communicate with the outside by forming an annular channel with the implantation portion. In operation, through piston vibration, form convection type heat dissipation. The heat loss and overheating damage caused by temperature rise can be effectively reduced. The working efficiency and the reliability of the system are improved.

To sum up, by adopting the technical scheme of the utility model and combining the attached drawings 12-14, the utility model has the following advantages:

implanted structure-effectively reduces non-linear distortion, improves heat dissipation efficiency, increases system reliability and expands f_{On the upper part}。

The same index type transmission structure, namely each subdivision sound wave channel, adopts the same index model waveguide structure, so that the sound wave transmission characteristics are consistent and the distortion is minimized.

The equiphase transmission design-the innovative equivalent simulation algorithm is provided, so that the calculation of the acoustic path is greatly simplified, and the foundation is laid for realizing equiphase and coupling superposition of each acoustic channel.

Equal transmission ratio design-innovative proposing equal transmission ratio concepts. The equivalent rate transmission of each sound wave channel is realized.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and for those skilled in the art, the present invention may have various modifications, combinations and variations, especially, manufacturing errors, and it is impossible for each sound wave channel of the phase plug to have the transmission ratio equal and equal phase (the analog sound path is equal), and it is also possible for a in the index model in different sound wave channels to have errors, but any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A phase plug for sound amplification, comprising: the acoustic wave channel structure comprises more than two annular acoustic wave channels, the cross sections of the acoustic wave channels are exponential type cross sections, the area ratio of an input port to an output port of each acoustic wave channel is the same, and the phases of acoustic waves in the acoustic wave channels are equal.

2. Phase plug for sound reinforcement according to claim 1, characterized in that: the section of the acoustic channel comprises a section line q near the center of the phase plug_iAnd an exponential cross-sectional curve y near the outside of the phase plug_iAnd i refers to the ith acoustic channel from the center of the phase plug to the outer side.

3. Phase plug for sound reinforcement according to claim 2, characterized in that: exponential cross-sectional curve y_iIs expressed as y_i=a^xWherein a is a constant and greater than 1.

4. Phase plug for sound reinforcement according to claim 2, characterized in that: the analog sound paths of the sound waves in the sound wave channels are equal, and the analog sound paths d of the sound waves in the sound wave channels are_i=q_i+c_iThe input end of the phase plug is a conical curved surface, and the section curve of the conical curved surface in the sound wave channel is c, E_iIs q_iPoint of intersection with c, c_iIs E_iAnd E₁The path length of the two points on the cross-sectional curve c.

5. Phase plug for sound reinforcement according to claim 4, characterized in that: e₁Is the simulated sound source point of the diaphragm.

6. Phase plug for sound reinforcement according to claim 2, characterized in that: s_i/s_i=b，S_iIs the output port area, s, of the ith acoustic channel_iB is a constant value, which is the input port area of the ith acoustic channel.

7. Phase plug for sound reinforcement according to claim 1, characterized in that: the phase plug comprises an input end with a conical curved surface and an implant body arranged in the middle of the input end, the outer diameter of the implant body is matched with the inner diameter of the intermediate frequency driver, the phase plug is implanted into the intermediate frequency driver through the implant body, and the conical curved surface is matched with a vibrating diaphragm of the intermediate frequency driver.