CN214851789U - Automobile rear-loading system based on bass EQ tuning - Google Patents

Abstract

The utility model relates to a car audio system field, specific system after car based on bass EQ tuning that says so, include: the system comprises an original automobile machine, a DSP power amplifier board, a loudspeaker, a terminal, a subwoofer and an audio voltmeter, wherein the original automobile machine, the DSP power amplifier board, the loudspeaker, the terminal, the subwoofer and the audio voltmeter are arranged in an automobile; the original car machine is connected with the DSP power amplification board through a 4-channel power input line, and the DSP power amplification board is connected with the plurality of loudspeakers through a 4-channel power output line; the subwoofer includes: the bass loudspeaker box body and an active bass loudspeaker and a passive bass loudspeaker which are arranged in the bass loudspeaker box body; the DSP power amplifier board is respectively connected with an active loudspeaker and an audio voltmeter of the subwoofer through a subwoofer connecting wire; the DSP power amplification board is provided with a DSP-USB port, and the DSP-USB port is connected with the terminal through a USB connecting wire. The utility model provides a former car dispatch of factory bass EQ default can not adapt to the problem of system after and the upgrading tone quality effect of current car audio system is poor, and is with high costs, the difficult problem of installation and debugging.

Description

Automobile rear-loading system based on bass EQ tuning

Technical Field

The utility model relates to a car audio system field, specific system is adorned after car based on bass EQ tuning that says so.

Background

With the rapid development of the car networking and automatic driving technology, people have higher and higher requirements on the sound quality of car audio, but the existing after-loading products in the prior art cannot meet the requirements of people, so that a brand-new car after-loading sound system with high sound quality and low cost and finished by car owners in DIY is urgently needed.

The traditional technical after-loading automobile sound equipment products are not upgraded with three schemes of replacing loudspeakers, adding subwoofers and adding DSP power amplifiers. The schemes have the defects of poor tone quality upgrading effect, high cost, difficulty in installation and debugging and incapability of finishing DIY by a vehicle owner.

SUMMERY OF THE UTILITY MODEL

Not enough to prior art, the utility model provides a system and tuning method after car based on bass EQ tuning to it is poor to solve current car audio system's upgrading tone quality effect, and is with high costs, the difficult problem of installation and debugging.

The utility model discloses a realize that the technical scheme that above-mentioned purpose adopted is: a vehicle afterloading system based on bass EQ tuning comprising: the system comprises an original automobile machine, a DSP power amplifier board, a loudspeaker, a terminal, a subwoofer and an audio voltmeter, wherein the original automobile machine, the DSP power amplifier board, the loudspeaker, the terminal, the subwoofer and the audio voltmeter are arranged in an automobile;

the original car machine is connected with a DSP power amplification board through a 4-channel power input line, and the DSP power amplification board is connected with a plurality of loudspeakers through a 4-channel power output line;

the subwoofer includes: the subwoofer includes: the bass loudspeaker box body and an active bass loudspeaker and a passive bass loudspeaker which are arranged in the bass loudspeaker box body; the DSP power amplification board is respectively connected with an active loudspeaker and an audio voltmeter of the subwoofer through a subwoofer connecting wire;

the DSP power amplification board is provided with a DSP-USB port, and the DSP-USB port is connected with a terminal through a USB connecting wire.

The subwoofer and the audio voltmeter are connected in parallel.

The DSP power amplifier board includes: the system comprises an EQ processor, a subwoofer volume adjuster, a subwoofer amplifier and a plurality of intermediate frequency series frequency division capacitors, wherein the DSP power amplifier board is provided with an input port and an output port;

the input port is connected with an original car machine through a 4-channel power input line, the input port is connected with the output port through a parallel circuit of a plurality of intermediate frequency series frequency division capacitors, and the output port is connected with a loudspeaker through a 4-channel power output line;

the input port is connected with the subwoofer power amplifier through the EQ processor and the subwoofer volume adjuster in sequence;

the subwoofer amplifier is respectively connected with the subwoofer and the audio voltmeter through a subwoofer connecting wire.

The EQ processor is a low-pass filter realized by adopting a DSP chip, and the EQ processor is a DSP chip for adjusting the EQ of bass.

The number of the loudspeaker sound channels is equal to that of the intermediate frequency series frequency division capacitors, and the sound channels of each loudspeaker are correspondingly connected with one intermediate frequency series frequency division capacitor.

The DSP power amplification board is also provided with a wireless system; and the terminal is connected with the EQ processor through a wireless system.

The active bass loudspeaker is embedded into the bass box body, and the mounting plane of the active bass loudspeaker is positioned on the plane of a certain side wall of the box body; the active bass loudspeaker is connected with a bass amplifier of the DSP power amplification board through a bass connecting wire;

the passive woofers are arranged in pairs, and each pair of passive woofers are correspondingly arranged in the bass box body.

The ratio of the diaphragm area of the active woofer to the total diaphragm area of the passive woofer is as follows: 1: 1.5-2.5.

The audio voltmeter is any one of a digital alternating current voltmeter, an analog pointer alternating current voltmeter and a universal meter.

The subwoofer volume adjuster is a physical potentiometer or an electric control volume adjuster.

The utility model has the following beneficial effects and advantages:

1. the utility model discloses the DSP power amplifier is provided with subwoofer volume adjuster, through adjusting this subwoofer volume adjuster, just can make whole back-loading bass, middle pitch and high pitch of stereo set reach the balance, obtain best tone quality.

2. The utility model discloses with low costs, only need hundreds of yuan of RMB just can surpass the traditional car of thousands of yuan of back dress stereo set tone quality.

3. The utility model discloses it is small, light in weight, easy installation, not broken line, really harmless installation, car owner oneself DIY just can accomplish.

4. The utility model discloses a three frequency division electro-acoustic conversion, bass are sent by the subwoofer, and the well pitch is sent by the well woofer that only sends the well pitch, and the high pitch is sent by high pitch loudspeaker, and each speaker full play advantage separately, greatly reduced reduction distortion realizes high-fidelity electro-acoustic reduction, and tone quality is better.

5. The utility model discloses a subwoofer has adopted and has corresponded the setting around the passive woofer in pairs, forms multiple heavy bass and increases, and bass EQ compensates the tuning in addition, makes the bass more mellow and full, and is more flexible, and is thicker and heavier, and it is better than the 15 car subwoofers effects that rise of 8 cun double voice coils of traditional art.

6. The utility model discloses a back dress sound system of car has still followed former car machine and former car speaker, has reduced the distortion, has practiced thrift the spending for the car owner.

Drawings

Fig. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic structural diagram of the present invention with wireless communication function;

FIG. 3a is a partial cross-sectional view of a top view of the subwoofer of the present invention;

FIG. 3b is a front view of the subwoofer of the present invention;

wherein, 1 is former car machine, 2 is 4 sound channel power input lines, 3 is wireless system, 4 are DSP amplificatory board, 5 are EQ treater, 6 are subwoofer amplificator, 7 are DSP-USB port, 8 are the USB connecting wire, 9 are computer USB port, 10 are the computer, 11 are subwoofer output cable, 12 are the subwoofer, 13 are the audio frequency voltmeter, 14 are intermediate frequency series connection frequency division electric capacity, 15 are 4 sound channel power output line subwoofer amplificator, 16 are the speaker, 18 are the subwoofer box, 19 are initiative subwoofer, 20 are passive subwoofer, 21 are subwoofer volume adjuster.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The present invention will be described in detail with reference to the accompanying drawings.

The utility model discloses a sound system behind car based on voltage EQ tuning, including the former car machine 1 that installs respectively in the car, 4 sound track power input lines 2, bluetooth system 3, DSP power amplifier board 4, EQ treater 5, subwoofer power amplifier 6, DSP-USB port 7, USB connecting wire 8, computer USB port 9, computer 10, subwoofer connecting wire 11, subwoofer 12, audio frequency voltmeter 13, intermediate frequency series connection frequency-division capacitor 14, new 4 sound track output line 15, speaker 16, subwoofer volume adjuster 21;

as shown in fig. 1, which is a schematic structural diagram of the present invention, wherein an original car machine 1 is connected to a DSP power amplifier board 4 through a 4-channel power input line 2, and the DSP power amplifier board 4 is connected to a plurality of speakers 16 through a 4-channel power output line 15;

the subwoofer 12 includes: a subwoofer box 18 and an active subwoofer 19 and a passive subwoofer 20 disposed within the subwoofer box 18; the DSP power amplification board 4 is respectively connected with an active bass loudspeaker 19 and an audio voltmeter 13 of a subwoofer 12 through a subwoofer connecting wire 11;

the DSP power amplification board 4 is provided with a DSP-USB port 7, and the DSP-USB port 7 is connected with a terminal through a USB connecting wire 8. The subwoofer 12 is connected in parallel with the audio voltmeter 13, or the subwoofer 12 is not connected, and the audio voltmeter 13 is connected with the subwoofer connecting wire 11, namely, the audio voltmeter 13 measures the low-frequency output voltage in the no-load state.

The DSP power amplifier board 4 includes: the system comprises an EQ processor 5, a subwoofer volume adjuster 21, a subwoofer power amplifier 6 and a plurality of intermediate frequency series frequency division capacitors 14, wherein a DSP power amplifier board 4 is provided with an input port and an output port;

the input port is connected with the original car machine 1 through a 4-channel power input line 2, the input port is connected with the output port through a parallel circuit of a plurality of intermediate frequency series frequency-division capacitors 14, and the output port is connected with a loudspeaker 16 through a 4-channel power output line 15;

the input port is connected with the subwoofer power amplifier 6 through the EQ processor 5 and the subwoofer volume adjuster 21 in sequence;

the subwoofer power amplifier 6 is respectively connected with a subwoofer 12 and an audio voltmeter 13 through a subwoofer connecting wire 11, the subwoofer power amplifier 6 can be directly connected with the audio voltmeter 13, and the subwoofer 12 is replaced by a resistor or is connected with a no-load;

the EQ processor 5 is a low-pass filter implemented using a DSP chip, and the EQ processor 5 is a DSP chip that adjusts EQ of bass.

The number of sound channels of the loudspeaker 16 is equal to that of the intermediate frequency series frequency-dividing capacitor 14, and the sound channel of each loudspeaker 16 is correspondingly connected with one intermediate frequency series frequency-dividing capacitor 14.

As shown in fig. 2, the DSP power amplifier board 4 is further provided with a wireless system 3; the terminal is connected with the EQ processor 5 through the wireless system 3; in this embodiment, the wireless system 3 is a bluetooth device;

as shown in fig. 3 a-3 b, the active woofer 19 is embedded in the subwoofer box 18 and its installation plane is located on the plane of one side wall of the box; the active bass loudspeaker 19 is connected with the bass amplifier 6 of the DSP power amplifier board 4 through a bass connecting wire 11;

the passive woofers 20 are arranged in pairs, with each pair of passive woofers 20 being disposed within the subwoofer cabinet 18 in correspondence with one another.

4 paths of audio power signals (high level) output by the original car machine 1 are input into a DSP power amplification board 4 through a 4-channel power input line 2, 4 paths of intermediate frequency series frequency division capacitors 14 are arranged in the DSP power amplification board 4, each path of the 4 paths of audio power output is connected with one intermediate frequency division capacitor in series, and the intermediate frequency division capacitors are respectively connected to corresponding Front Left (FL), Front Right (FR), Rear Left (RL) and Rear Right (RR) loudspeakers through a new 4-channel output line 15 and an original car wiring harness. Thus, a passive LC physical intermediate frequency divider is formed by the intermediate frequency dividing capacitor C and the loudspeaker voice coil inductance L, and only the intermediate and high pitch signals are allowed to pass through the divider, and the low pitch signal is cut off.

The DSP power amplifier board 4 is provided with an EQ processor 5, and the EQ processor 5 realizes built-in audio DSP and EQ by a DSP chip. In the DSP power amplifier board 4, the wireless system 3 is provided, and in this embodiment, a bluetooth system is adopted to communicate with the smart phone 22, so as to adjust the volume of the low-frequency EQ on the DSP chip and the bass volume on the interface of the smart phone. In addition, this DSP chip passes through DSP-USB port 7 and connects through USB connecting wire 8 and computer USB port, and computer 10 passes through the APP software of DSP and EQ to the realization changes the signal of low and signal mixture to 4 way audio power signals that come from former car machine and carries out subwoofer frequency division DSP bass enhancement and EQ tuning, and the signal after handling is output for subwoofer low frequency signal for subwoofer power amplifier 6, and the EQ tuning here has two functions: the bass frequency divider serving as an active electronic frequency divider passes low-frequency signals in full-frequency audio power signals from the original car machine 1, and blocks middle-pitch and high-pitch audio signals. Secondly, the EQ tuning is used for compensating the difference of the models of the original car machine 1 which leaves the factory EQ so as to meet the frequency requirement of the car audio installed afterwards, so that the bass of the car audio installed afterwards can be adjusted to the best tone quality. For example, some japanese toyota cars, such as: the attenuation of the original car machine EQ of the card roller to 20Hz-70Hz bass is very large, the bass of the after-loading car audio cannot be well represented by 30Hz-70Hz bass, and the difficulty can be effectively solved by adding 30Hz-70Hz bass through the EQ tuning of the after-loading system, so that the after-loading car audio product can be suitable for any car type and year of any car factory all over the world. The subwoofer power amplifier 6 is connected with the subwoofer 12 and the audio voltmeter 13 through a subwoofer connecting wire 11, the subwoofer 12 is connected with the audio voltmeter 13 in parallel, or the subwoofer 12 is not connected and replaced by a resistor when the EQ is tuned in order to reduce the inductive load of the active subwoofer 19, and the requirements can be met under the no-load condition.

The audio voltmeter 13 is an important component of the EQ tuning, the audio voltmeter 13 is used for measuring output voltage values of all frequencies of the low-frequency subwoofers outputted by the subwoofer power amplifier 6 at the end of playing of the original car machine 1, the audio voltmeter 13 can compare the relative sizes of the bass audio voltage values to perform EQ tuning on the computer 10 by comparing with an optimal tuning data table, and finally, under the guidance of an EQ tuning guide book and an optimal tuning data table, the EQ tuning data table meets and is close to the relative amplitude proportion requirement of each low-frequency of the optimal tuning data table, and the optimal tuning data table is the optimal data of the after-loading system, which is given by a post-loading system manufacturer after the company is repeatedly tuned and researched by professional tuners and engineers, and meets and is close to the data table requirement, namely, the data table is equivalent to the EQ tuning reaching a better level. In this way, the subwoofer volume is adjusted by the subwoofer volume adjuster 21 so that the bass, midrange and treble of the aftermount audio system are relatively balanced and the entire aftermount audio system is tuned to the desired state. The audio voltmeter 13 is an ac voltmeter, which may be a digital ac voltmeter, an analog pointer ac voltmeter, or an ac voltage level of a multimeter. The subwoofer volume adjuster 21 may be electronic software or may be a general potentiometer.

The first embodiment is as follows:

as shown in fig. 1, the rear-mounted EQ tuning system for car audio of the present embodiment includes an original car machine 1, a DSP power amplifier board 4, a computer 10, a subwoofer 12, front left, right, rear left and right speakers 16, and an audio voltmeter 13.

The original car machine 1 is the existing car radio of the original car, also called car multimedia playing system or car CD machine, the DSP power amplifier board 4 is a PCB board, on which there are the intermediate frequency series frequency dividing capacitor 14, DSP and EQ processor 5, subwoofer volume adjuster 21, subwoofer power amplifier 6. The original car machine 1 is connected with the DSP power amplifier board 4 through a 4-channel power output line 2, namely, four paths of high-level power signals of Front Left (FL), Front Right (FR), Rear Left (RL), Rear Right (RR) and four paths of high-level power signals output by the audio power amplifier of the original car machine are input into the DSP power amplifier board 4, each of the four input paths is connected in series with a middle frequency series frequency-dividing capacitor (14), and is respectively transmitted to a front left loudspeaker 16, a front right loudspeaker 16, a rear left loudspeaker 16 and a rear right loudspeaker 16 through an original vehicle wiring harness of a new 4-channel output line 15, wherein the front left loudspeaker 16, the front right loudspeaker 16, the rear left loudspeaker 16 and the rear right loudspeaker are middle bass loudspeakers and high pitch loudspeakers of an original vehicle, or the loudspeakers of the original vehicle are replaced by new loudspeakers, the woofer of the 4 paths of loudspeakers in about 6 inches is arranged at the lower part of 4 vehicle doors or on a vehicle rear window platform, or on the front instrument desk, the high pitch loudspeaker is arranged on the upper parts of the left and right A columns or the vehicle door, or on the front instrument desk. The high pitch loudspeaker is connected in series with a capacitor of 2.2-4.7 microfarads, the capacitor C and the voice coil inductance L of the high pitch loudspeaker form an LC passive high pitch frequency divider, the frequency divider is about 5KHz, namely, the audio frequency higher than 5KHz is input to the high pitch loudspeaker through the frequency divider, and the audio frequency lower than 5KHz cannot pass through the frequency divider.

Each path of the midrange frequency divider is a passive midrange frequency divider formed by one capacitor C of a midrange series frequency dividing capacitor 14 and respective front left, right, rear left and right midrange loudspeaker voice coil inductors L, the capacitance of each path of the frequency dividing capacitor C is about 40-200 microfarads, the embodiment is a 100 microfarad nonpolar capacitor, thus the frequency dividing point is about 120Hz, namely, a middle and high frequency signal higher than about 120Hz passes through, a low frequency signal lower than about 120Hz cannot pass through, and the larger the capacitance is, the lower the frequency dividing point is; the smaller the capacitance, the higher the frequency of the frequency division point.

The original car machine 1 inputs 4 sound track power signals of DSP power amplifier board 4, input to DSP and EQ processor 5 at the same time, here should carry on the high-level signal of these 4 sound tracks to turn high to low (namely high level turn low level) first, then input DSP and EQ processor 5 after mixing these 4 low level signals, form the bass low frequency signal after the active bass low frequency divider of DSP and EQ processor 5 is processed, finish the volume adjustment of the bass by the volume adjuster 21 of the bass, then input to the bass power amplifier 6, carry on the low-frequency power amplification; the subwoofer power output by the subwoofer power amplifier 6 is transmitted to the subwoofer 12 and the audio voltmeter 13 through the subwoofer connecting wire 11, and the audio voltmeter 13 is connected with the subwoofer 12 in parallel. Or the subwoofer 12 is unloaded, namely the subwoofer 12 is not connected, the subwoofer connecting wire 11 is only connected with the audio voltmeter 13, and the effect is the same. The audio voltmeter 13 is a general AC voltmeter, which may be a digital AC voltmeter, an analog pointer AC voltmeter, or an AC voltage range of a multimeter, and the range thereof is only AC 10V. The embodiment is an alternating voltage gear of the digital multimeter.

The DSP and EQ processor 5 is also connected with a computer 10 through a DSP-USB port 7, a USB connecting line 8 and a computer USB port 9. Thus, the DSP and EQ processor 5 can be tuned by software on the computer 10. The tuned value of the software package becomes the default value of the subwoofer EQ of the automobile audio equipment. The terminal 10 may be a notebook computer or a desktop computer. The embodiment adopts a notebook computer.

Example two:

as shown in fig. 2, the present embodiment is different from the first embodiment in that: the DSP-USB port 7, the USB connecting wire 8, the computer USB port 9 and the computer 10 of the first embodiment are cancelled, the Bluetooth system 3 and the smart phone 22 are replaced, namely the Bluetooth is arranged on the DSP power amplifier board 4, the wireless connection between the DSP and EQ processor 5 and the smart phone 22 is realized through the Bluetooth system 3, an EQ tuning and subwoofer volume adjustment APP interface is arranged on the smart phone 22, a user can operate on the interface to complete the EQ tuning and subwoofer volume adjustment, the final result is stored in the DSP and EQ processor 5, a default value is formed, and then the set EQ and subwoofer volume is obtained when the car is started every time. The rest is the same as the first embodiment.

Example three:

as shown in fig. 3a and 3b, the subwoofer 12 of the automobile afterloading system of the present embodiment is composed of a subwoofer box 18, an active woofer 19 and a passive woofer 20. The passive woofers 20 are correspondingly arranged in pairs, and the subwoofer box 18 is a closed cavity which can be made of metal materials or plastics, and in this embodiment, the subwoofer box is made of aluminum profiles and plastics. The volume of the automobile super-thin seat is about 2.7 liters, which is only half of the volume of a subwoofer under a traditional automobile super-thin seat, and the automobile super-thin seat is 298mm long, 199mm wide, 199mm thick and 66mm thick, so that the automobile super-thin seat is easier and more convenient to install in an automobile with limited space. The ratio of the diaphragm area of the active woofer 19 to the diaphragm area of the passive woofer 20 is 1:1.5 to 2.5, in this embodiment, 1:2, that is, the active woofer 19 is a 1-4 inch woofer unit, the passive woofer 20 is a 2-4 inch passive woofer unit, and the pair of passive woofers are symmetrically arranged in front of and behind each other or in a top-bottom manner.

The manufacturing cost of the subwoofer 12 is only 20% of that of the subwoofer under the ultrathin seat of the automobile in the traditional technology, but the bass tone quality of the subwoofer is far better than that of the subwoofer under the ultrathin seat of the automobile in the traditional technology, and the bass effect of the subwoofer is better than that of the subwoofer of the automobile with the 8-inch double voice coils and the 20-liter volume high-end in the traditional technology.

The utility model discloses a theory of operation does:

when the original car machine 1 plays a low-frequency sinusoidal audio signal of 40Hz … … 120Hz, the audio voltmeter 13 measures and tabulates voltage values of various frequencies, compares the relative voltage values of various frequencies, finds out the relative difference, compares with the optimal tuning data table of the merchant, performs EQ tuning on the terminal, and repeats the above processes repeatedly. Until the relative proportion of the low frequency frequencies reaches the relative proportion shown in the best tuning data table provided by the merchant.

The method specifically comprises the following steps: 1) playing the audio frequency of the low-frequency sinusoidal constant amplitude signal with the same level at the original car machine 1; the original car machine 1 transmits the audio frequency to the DSP power amplifier board 4 through the 4-channel power input line 2;

2) each sound channel power amplification signal passes through a corresponding intermediate frequency series frequency division capacitor 14, and after the intermediate frequency divider 13 separates out the middle pitch and the high pitch, the sound channel power amplification signal respectively drives a corresponding sound channel loudspeaker 16 in a corresponding original vehicle through a 4-channel power output line 15 to complete the electro-acoustic conversion of the middle pitch and the high pitch;

3) the EQ processor 5 inputs the audio frequency of the low-frequency sinusoidal constant amplitude signal into a subwoofer power amplifier 6; the low-frequency power output by the subwoofer amplifier 6 drives the subwoofer 12 through the subwoofer connecting wire 11 to complete the bass-electric-to-sound conversion.

4) Measuring the voltage value of each bass frequency in the low-frequency sinusoidal constant amplitude signal through an audio voltmeter 13, and recording a list;

5) comparing the relative values of the voltages recorded in the list in the step 4) according to the EQ tuning instruction and the relative values of the optimal tuning data table to obtain a comparison relative difference value;

6) and according to the comparison relative difference, performing EQ adjustment and data storage on the terminal.

Therefore, different factory EQ tuning values of the original car machine of different car models and different year styles can be tuned and compensated to the requirements of the rear sound gun system of the car of the merchant so as to achieve the optimal sound quality corresponding to different car families (Japanese, American, European, domestic and the like) all over the world.

The utility model discloses realized the high-fidelity electroacoustic reduction of three frequency division electroacoustic conversion in the car, the car owner is under no any stereo set EQ tuning technique and experience, and DIY oneself accomplishes the tuning, makes the afterloading car audio system EQ special car of trade company join in marriage, reaches best tone quality.

Claims (10)

1. An after-loading system for a vehicle based on bass EQ tuning, comprising: the system comprises an original car machine (1) arranged in a car, a DSP power amplifier board (4), a loudspeaker (16), a terminal, a subwoofer (12) and an audio voltmeter (13);

the original car machine (1) is connected with the DSP power amplification board (4) through a 4-channel power input line (2), and the DSP power amplification board (4) is connected with a plurality of loudspeakers (16) through a 4-channel power output line (15);

the subwoofer (12) comprises: a subwoofer box body (18), and an active subwoofer (19) and a passive subwoofer (20) which are arranged in the subwoofer box body (18); the DSP power amplification board (4) is respectively connected with an active bass loudspeaker (19) of a subwoofer (12) and an audio voltmeter (13) through a subwoofer connecting wire (11);

the DSP power amplification board (4) is provided with a DSP-USB port (7), and the DSP-USB port (7) is connected with a terminal through a USB connecting wire (8).

2. The bass EQ tuning-based after-loading system in a vehicle according to claim 1, wherein the subwoofer (12) and the audio voltmeter (13) are connected in parallel.

3. The system for afterloading a bass EQ tuning-based vehicle according to claim 1, wherein the DSP power board (4) comprises: the system comprises an EQ processor (5), a subwoofer volume adjuster (21), a subwoofer power amplifier (6) and a plurality of intermediate frequency series frequency division capacitors (14), wherein the DSP power amplifier board (4) is provided with an input port and an output port;

the input port is connected with an original car machine (1) through a 4-channel power input line (2), the input port is connected with an output port through a parallel circuit of a plurality of intermediate frequency series frequency division capacitors (14), and the output port is connected with a loudspeaker (16) through a 4-channel power output line (15);

the input port is connected with a subwoofer power amplifier (6) through an EQ processor (5) and a subwoofer volume adjuster (21) in sequence;

the subwoofer power amplifier (6) is respectively connected with the subwoofer (12) and the audio voltmeter (13) through a subwoofer connecting wire (11).

4. The afterloading system for bass EQ tuning according to claim 3, wherein the EQ processor (5) is a low-pass filter and the EQ processor (5) is a DSP chip for EQ adjustment of bass.

5. The system as claimed in claim 1 or 3 wherein the number of channels of loudspeakers (16) is equal to the number of midrange series crossover capacitors (14) and one midrange series crossover capacitor (14) is associated with each channel of loudspeakers (16).

6. The system for afterloading a bass EQ tuning-based automobile according to claim 1, wherein a wireless system (3) is further arranged on the DSP power amplifier board (4); and the terminal is connected with the EQ processor (5) through a wireless system (3).

7. The bass EQ tuning-based after-loading system in a vehicle according to claim 1, wherein the active woofer (19) is embedded in the subwoofer box (18) with its mounting plane in the plane of one of the side walls of the box; the active bass loudspeaker (19) is connected with a bass amplifier (6) of the DSP power amplification board (4) through a bass connecting wire (11);

the passive woofers (20) are arranged in pairs, and each pair of the passive woofers (20) are correspondingly arranged in the subwoofer box body (18).

8. The bass EQ tuning-based after-loading system of claim 1, wherein the ratio of the diaphragm area of the active woofer (19) to the total diaphragm area of the passive woofers (20) is: 1: 1.5-2.5.

9. The system in claim 1, wherein the audio voltmeter (13) is any one of a digital ac voltmeter, an analog pointer ac voltmeter and a multimeter.

10. The bass EQ tuning-based after-loading system in a vehicle according to claim 3, wherein the subwoofer volume adjuster (21) is a physical potentiometer or an electrically controlled volume adjuster.

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