Loudspeaker system
By using low-pass and high-pass filters to divide the frequency band in the vehicle speaker system, the problem of mid-frequency sound image shift is solved, sound quality is maintained and components are reduced, and frequency band overlap and overcurrent phenomena are avoided.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YAMAHA CORP
- Filing Date
- 2022-11-21
- Publication Date
- 2026-06-23
AI Technical Summary
In a three-way speaker system in a car, the sound image of mid-frequency sounds tends to shift downwards, causing passengers to feel a sense of disharmony due to the inconsistent sound source position, especially when playing singing sounds in the 500Hz to 2kHz frequency range.
Low-pass and high-pass or band-pass filters are used to divide the frequency band in the loudspeaker system to ensure that the frequency response crossover frequency of the low-frequency and mid-frequency loudspeakers is below 300Hz. Impedance is adjusted by resistors to avoid overcurrent, and first-order filters are used to reduce the number of components.
It effectively reduces the downward offset of the mid-frequency sound image, maintains sound quality, reduces the number of components, and avoids sound quality degradation and overcurrent problems caused by frequency band overlap.
Smart Images
Figure CN116198425B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to speaker systems, and more particularly to speaker systems installed in vehicles such as passenger cars. Background Technology
[0002] A multi-channel loudspeaker system includes a channel splitting network that divides the input audio signal into each frequency band, and a dedicated single loudspeaker unit corresponding to each frequency band. Patent Document 1 is cited as prior art related to multi-channel loudspeaker systems. Patent Document 1 describes the use of even-order Butterworth filters or Linkwits-Riley type filters to divide the audio signal into each frequency band.
[0003] Patent Document 1: Japanese Utility Model Application Publication No. 4-67895 Summary of the Invention
[0004] In a three-way car speaker system comprising a tweeter for high-frequency sounds, a mid-frequency speaker for mid-frequency sounds, and a bass speaker for low-frequency sounds, the bass speaker is typically positioned in the lower part of the car door, etc. To ensure that the position of the sound image obtained from the sound played by the mid-frequency speaker corresponds to the ear position of the vehicle occupants, the mid-frequency speaker is usually positioned above the bass speaker located on the vertical axis, above the bass speaker located in the upper part of the car door, etc. In this speaker layout, problems arise if the frequency bands of the sounds played by the bass speaker and mid-frequency speaker are not properly allocated. For example, consider a speaker system that repeatedly distributes sounds with frequency components of 300Hz to 500Hz to play singing sounds. Typically, since the frequency band of singing sounds is 400Hz to 2kHz, the bass speaker with frequency components of 500Hz to 2kHz...
[0005] The vocal frequencies above 500Hz are output solely from the mid-range speaker. Conversely, vocal frequencies below 500Hz are output from both the mid-range and low-frequency speakers. The sound image of vocals with frequency components between 500Hz and 2kHz is obtained solely from the playback sound from the mid-range speaker, thus placing this sound image at the position of the occupant's ears. Conversely, the sound image of vocals below 500Hz is obtained from both the playback sound from the mid-range speaker and the playback sound from the low-frequency speaker, placing this sound image between the mid-range and low-frequency speakers. In other words, the sound image of vocals below 500Hz is shifted to a position lower than the occupant's ears. Therefore, for vocals with frequency components between 500Hz and 2kHz and vocals with frequency components lower than 500Hz and 2kHz, the vehicle occupant may experience a sense of disharmony, as if the sound source positions appear different.
[0006] The present invention was made in view of the above situation, and its solution is to reduce the downward shift of the sound image of the mid-frequency sound in a vehicle speaker system having a first speaker responsible for playing low-frequency sound and a second speaker configured on the vertical axis above the first speaker and responsible for playing mid-frequency sound.
[0007] One aspect of the present invention relates to a loudspeaker system comprising a first loudspeaker, a second loudspeaker, a first filter, and a second filter. The first and second loudspeakers are disposed in a vehicle equipped with the loudspeaker system. The second loudspeaker is positioned above the first loudspeaker along a vertical axis. The first filter is disposed between the output terminal of an amplification device that outputs an audio signal to the loudspeaker system and the first loudspeaker. The second loudspeaker is disposed between the output terminal and the second loudspeaker. The first filter is a low-pass filter. The second filter is a high-pass filter or a band-pass filter. In this loudspeaker system, the crossover frequency between the frequency response of the first output system comprising the first filter and the first loudspeaker and the frequency response of the second output system comprising the second filter and the second loudspeaker is 300 Hz or less. Attached Figure Description
[0008] Figure 1 This is a diagram illustrating a structural example of a loudspeaker system 1A according to an embodiment of the present invention.
[0009] Figure 2 This is a diagram showing an example configuration of a low-frequency speaker 31, a mid-frequency speaker 32A, and a high-frequency speaker 33 in a vehicle C equipped with a speaker system 1A.
[0010] Figure 3 This is a diagram showing an example of the equivalent circuit of a loudspeaker.
[0011] Figure 4 This is a diagram showing an example of the structure of filter 111.
[0012] Figure 5 This is a diagram showing an example of the structure of filter 112.
[0013] Figure 6 This is a graph showing the frequency response of first-order, second-order, third-order, and fourth-order low-pass filters.
[0014] Figure 7 This is a diagram showing an example of the frequency response of filters 111, 112, and 113.
[0015] Figure 8 This is a diagram illustrating a structural example of an existing loudspeaker system 1D.
[0016] Figure 9 This is a diagram illustrating a structural example of a loudspeaker system 1E with a reduced number of components compared to the existing loudspeaker system 1D.
[0017] Figure 10 This is a graph showing an example of the frequency response of the impedance of the speaker system 1E when the cutoff frequency of filter 112 is 464Hz.
[0018] Figure 11 This is a diagram showing an example of the frequency response of the impedance of loudspeaker system 1A.
[0019] Figure 12 This is a graph showing an example of sound pressure level measurements for each frequency of a sound played in loudspeaker system 1A.
[0020] Figure 13 This is a diagram showing a structural example of the loudspeaker system 1B involved in the modified example (3).
[0021] Figure 14 This is a diagram showing a structural example of the loudspeaker system 1C involved in the modified example (4). Detailed Implementation
[0022] A. Implementation Method
[0023] Figure 1 This is a diagram illustrating a structural example of a loudspeaker system 1A according to an embodiment of the present invention. The loudspeaker system 1A is a three-way loudspeaker system comprising a channel splitting network 10A, a low-frequency loudspeaker 31, a mid-frequency loudspeaker 32A, and a high-frequency loudspeaker 33. The low-frequency loudspeaker 31 is responsible for playing low-frequency sounds. The mid-frequency loudspeaker 32A is responsible for playing mid-frequency sounds. The high-frequency loudspeaker 33 is responsible for playing high-frequency sounds. Although in Figure 1 The diagram shows one low-frequency speaker 31, one mid-frequency speaker 32A, and one high-frequency speaker 33. However, the speaker system 1A may also include multiple speaker groups consisting of low-frequency speakers 31, mid-frequency speakers 32A, and high-frequency speakers 33.
[0024] The speaker system 1A is a vehicle-mounted speaker system installed in a vehicle. Figure 2 This diagram illustrates an example configuration of the low-frequency speaker 31, mid-frequency speaker 32A, and high-frequency speaker 33 in a vehicle C equipped with a speaker system 1A. In vehicle C, the driver's seat is located on the right side and the passenger seat on the left side, relative to the direction of travel. Vehicle C is used in Japan, India, the United Kingdom, Australia, and African countries, among others. Furthermore, the configuration of the driver's seat and passenger seat can be reversed. Such vehicles are used in China, Germany, France, Italy, and the United States, among others. Figure 2As shown, the high-frequency speaker 33 is positioned in the console CS of vehicle C closer to the driver's seat than the passenger seat. The low-frequency speaker 31 and the mid-frequency speaker 32A are positioned in the front door D of vehicle C closer to the driver's seat than the passenger seat. More specifically, the low-frequency speaker 31 is positioned in the front door D closer to the floor F than the driver's seat surface SS. On the other hand, in order to make the position of the sound image obtained by the sound played from the mid-frequency speaker 32A correspond to the ear position of the passenger sitting in the driver's seat, the mid-frequency speaker 32A is positioned in the front door D closer to the pillar P than the driver's seat surface SS. That is, the mid-frequency speaker 32A is located higher than the low-frequency speaker 31 in the vertical axis Z along the vertical direction in vehicle C. Furthermore, in Figure 2 The symbol TR refers to the trunk in vehicle C. If the speaker system 1A also includes another set of low-frequency speakers 31, mid-frequency speakers 32A, and high-frequency speakers 33, the other set of low-frequency speakers 31, mid-frequency speakers 32A, and high-frequency speakers 33 can also be located in the front door of vehicle C, closer to the passenger seat than the driver's seat, and in the console CS, closer to the passenger seat than the driver's seat.
[0025] In this embodiment, the impedances of the low-frequency speaker 31, the mid-frequency speaker 32A, and the high-frequency speaker 33 are all 4Ω, the same as those of a typical speaker. The impedances of the low-frequency speaker 31, the mid-frequency speaker 32A, and the high-frequency speaker 33 are based on the following... Figure 3 The equivalent circuit shown was calculated through simulation. Figure 3 This is a diagram showing an example of the equivalent circuit of a loudspeaker. Figure 3 The inductance value of inductor Le1 is a parameter corresponding to the inductance value of the speaker's voice coil, and the resistance value of resistor Re1 is a parameter corresponding to the DC resistance of that voice coil. Figure 3 The capacitance value of capacitor Cms1, the inductance value of inductor Lms1, and the resistance value of resistor Rms1 are parameters determined based on the diaphragm, damper, and edge of the speaker.
[0026] like Figure 1 The channel splitting network 10A shown splits the audio signal Sin input to the speaker system 1A into a low-frequency audio signal S1, a mid-frequency audio signal S2, and a high-frequency audio signal S3. Audio signal S1 is supplied to the low-frequency speaker 31. Audio signal S2 is supplied to the mid-frequency speaker 32A. Audio signal S3 is supplied to the high-frequency speaker 33.
[0027] In addition to speaker system 1A Figure 1The diagram also shows an amplification device 2 that supplies the sound signal Sin to the speaker system 1A. The amplification device 2 has an output terminal 20 that outputs the sound signal Sin. The output terminal 20 is connected to a channel splitting network 10A. Sound signals from in-vehicle audio devices such as CD (Compact Disk) players are supplied to the amplification device 2. Figure 1 The diagram omits the in-vehicle audio device that supplies the sound signal to the amplification unit 2. The sound signal supplied from the in-vehicle audio device to the amplification unit 2 is, for example, a sound signal representing singing. The amplification unit 2 amplifies the sound signal supplied from the in-vehicle audio device. The amplification unit 2 outputs the amplified sound signal as the sound signal Sin from the output terminal 20.
[0028] like Figure 1 As shown, the channel splitting network 10A includes filters 111, 112, 113, resistor 121, and resistor 122. In this embodiment, resistor 121 has a resistance of 0.5Ω, and resistor 122 has a resistance of 1Ω. Filter 111 and resistor 121 are connected in series between the output terminal 20 of the amplifier 2 and the low-frequency speaker 31. Filter 111, resistor 121, and low-frequency speaker 31 constitute the output system SL1, which outputs low-frequency sound. Filter 112 and resistor 122 are connected in series between the output terminal 20 and the intermediate frequency speaker 32A. Filter 112, resistor 122, and intermediate frequency speaker 32A constitute the output system SL2, which outputs intermediate-frequency sound. Filter 113 is disposed between the output terminal 20 and the high-frequency speaker 33. In this embodiment, filter 113 and high-frequency speaker 33 constitute the output system SL3, which outputs high-frequency sound.
[0029] Filter 111 is a low-pass filter. In this embodiment, the cutoff frequency of filter 111 is set to 288Hz. Filter 111 attenuates frequency components in the audio signal Sin supplied from amplification device 2 that are higher than 288Hz, thereby generating audio signal S1. The cutoff frequency refers to the frequency at the boundary between the passband and stopband of the filter. More specifically, the cutoff frequency is the frequency at which the output signal of the filter is attenuated by 3dB relative to the input signal.
[0030] Filter 112 is a high-pass filter. In this embodiment, the cutoff frequency of filter 112 is set to 276Hz. Filter 112 attenuates frequency components in the audio signal Sin supplied from amplification device 2 that have frequencies below 276Hz, thereby generating audio signal S2. Filter 113 is also a high-pass filter, similar to filter 112. In this embodiment, the cutoff frequency of filter 113 is set to 9.8kHz. Filter 113 attenuates frequency components in the audio signal Sin supplied from amplification device 2 that have frequencies below 9.8kHz, thereby generating audio signal S3.
[0031] In this embodiment, the cutoff frequency of filter 111 is 288Hz, but it is not limited to 288Hz as long as the cutoff frequency of filter 111 is below 300Hz. If the cutoff frequency of filter 111 is above 300Hz, sounds with frequencies around 300Hz are output from the low-frequency speaker 31 at a high sound pressure level. In this embodiment, sounds in the frequency band above 300Hz are mainly output from the mid-frequency speaker 32A. Assuming that the cutoff frequency of filter 111 is above 300Hz, sounds with frequencies around 300Hz are output from the low-frequency speaker 31. As a result, the position of the sound image of the sound around 300Hz is shifted downwards along the vertical axis Z from the position of the passenger's ear in the driver's seat. Therefore, in order to reduce the downward shift of the position of the sound image of the sound around 300Hz, the cutoff frequency of filter 111 is preferably below 300Hz.
[0032] Figure 4 This is a diagram showing an example of the structure of filter 111. Besides filter 111, Figure 4 The middle diagram shows the amplifier 2, resistor 121, and low-frequency speaker 31. (As shown...) Figure 4 As shown, filter 111 is a second-order low-pass filter composed of inductor L1 and capacitor C1. Figure 5 This is a diagram showing an example of the structure of filter 112. Besides filter 112, Figure 5 The image also shows an amplifier 2, a resistor 122, and an intermediate frequency loudspeaker 32A. (For example...) Figure 5 As shown, filter 112 is a first-order high-pass filter consisting only of capacitor C2. Filter 113 is also a first-order high-pass filter, just like filter 112.
[0033] Figure 6 This is a graph showing the frequency response of first-order, second-order, third-order, and fourth-order low-pass filters. Figure 6 In this context, the symbol FC represents the cutoff frequency. The symbol FL represents the lower limit frequency of the octave band centered at the cutoff frequency, and the symbol FH represents the upper limit frequency of that band. This can be represented as... Figure 6 The frequency responses shown are obtained by flipping them left and right around the cutoff frequency to obtain the frequency responses of first-order, second-order, third-order, and fourth-order high-pass filters. For example... Figure 6 As shown, compared to low-order filters, high-order filters exhibit a steeper attenuation in the stopband. Furthermore, the number of passive components constituting the filter increases with higher-order filters compared to low-order filters.
[0034] Typically, low-frequency speakers can output sound up to 4kHz. Therefore, to reduce the downward shift of the sound image from the occupant's ear position caused by the mid-frequency speaker 32A, the attenuation in the stopband of filter 111 is preferably steep. This is because the frequency bands of the sound from the mid-frequency speaker 32A and the low-frequency speaker 31 preferably do not overlap. For this purpose, in this embodiment, a second-order low-pass filter is used as filter 111. Compared to a first-order low-pass filter, the attenuation in the stopband of a second-order low-pass filter is steeper.
[0035] On the other hand, since filter 112 is a first-order high-pass filter, the sound signal S2 output from filter 112 may contain signal components with frequencies lower than the cutoff frequency of filter 112 without being sufficiently attenuated. Therefore, interference may occur between the playback sound from low-frequency speaker 31 and the playback sound from mid-frequency speaker 32A in the frequency band below the cutoff frequency of filter 112. However, the playback sound from mid-frequency speaker 32A typically attenuates in the frequency band below 200Hz. Furthermore, since the frequency band below 200Hz is below the lower limit of the singing sound frequency band, i.e., 400Hz, it has no particular impact on the sound quality of the singing sound played in speaker system 1A.
[0036] Furthermore, in this embodiment, both filters 112 and 113 are first-order high-pass filters, so interference may occur between the playback sound from the intermediate frequency speaker 32A and the playback sound from the high frequency speaker 33. However, in the frequency band where the playback sound from the intermediate frequency speaker 32A and the playback sound from the high frequency speaker 33 overlap, the frequency is high enough that the effect of phase interference is small, so no particular problem arises.
[0037] exist Figure 7 The diagram shows the frequency response curves G1 for filter 111, G2 for filter 112, and G3 for filter 113. The crossover frequency between the frequency responses of output system SL1 and output system SL2 is determined by the intersection point P1 of curves G1 and G2. The crossover frequency refers to the frequency at which the frequency responses of output system SL1 and output system SL2 intersect. In this embodiment, to keep this crossover frequency below 300Hz, the cutoff frequency of filter 112 is set to 276Hz.
[0038] In explaining the effects of this embodiment, a conventional three-way speaker system will be described in comparison. Figure 8This diagram illustrates the structure of a speaker system 1D, an example of an existing three-way speaker system. Comparing speaker system 1D and speaker system 1A, the difference between speaker system 1D and speaker system 1A is that speaker system 1D has a channel splitting network 10D instead of channel splitting network 10A. The channel splitting network 10D differs from channel splitting network 10A in the following three ways: First, a second-order high-pass filter 133 is used to generate sound signal S3. Second, a band-pass filter 132 is used to generate sound signal S2. The band-pass filter 132 is constructed by connecting a second-order high-pass filter and a second-order low-pass filter in series. Third, resistors 121 and 122 are absent.
[0039] When installing a three-way speaker system in vehicle C, it is necessary to reduce the number of components constituting the speaker system. To reduce the number of components in the existing speaker system 1D, it is conceivable to replace the high-pass filter 133 with filter 113, and the band-pass filter 132 with filter 112, such as... Figure 9 As shown in the speaker system 1E, by replacing the high-pass filter 133 with filter 113, an inductor can be omitted; by replacing the band-pass filter 132 with filter 112, the low-pass filter can be omitted, and another inductor can be omitted. Furthermore, even if a first-order high-pass filter is used to generate sound signal S3 and a first-order high-pass filter is used to generate sound signal S2, as mentioned earlier, no particular problems will occur in terms of sound quality. (Comparison) Figure 9 and Figure 1 It is evident that the channel splitting network 10E in the loudspeaker system 1E differs from the channel splitting network 10A in that it lacks resistors 121 and 122.
[0040] However, in such Figure 9In the loudspeaker system 1E shown, the cutoff frequency of filter 112 needs to be set to a frequency sufficiently high compared to the cutoff frequency of filter 111. The reason is as follows: In loudspeaker system 1E, when the cutoff frequencies of filter 112 and filter 111 are approximately equal, sound signals with frequencies close to these cutoff frequencies are supplied to the low-frequency speaker 31 and the mid-frequency speaker 32A. Because filter 112 is a first-order high-pass filter, the mid-frequency speaker 32A and the low-frequency speaker 31 are effectively connected in parallel at frequencies near the aforementioned cutoff frequency. When the low-frequency speaker 31 and the mid-frequency speaker 32A are connected in parallel to the amplifier 2, the combined impedance is lower than the impedance of a single low-frequency speaker 31 or a single mid-frequency speaker 32A. With this decrease in impedance, overcurrent may occur in the amplifier 2. To reduce the occurrence of this overcurrent, the cutoff frequency of filter 112 needs to be set sufficiently high compared to the cutoff frequency of filter 111 in loudspeaker system 1E.
[0041] Figure 10 This is a diagram showing an example of the frequency response of the speaker system 1E's impedance as observed from the output terminal 20 when the cutoff frequency of filter 111 is 288Hz and the cutoff frequency of filter 112 is set to 464Hz. Figure 10 In the example shown, the impedance in the 200-500Hz frequency band is sufficiently high compared to the impedance of the low-frequency speaker 31 or the mid-frequency speaker 32A, which is 4Ω, thereby reducing the overcurrent flowing through the amplifier 2 in this frequency band.
[0042] However, in speaker system 1E, if the cutoff frequency of filter 112 is set sufficiently high compared to the cutoff frequency of filter 111, the connection between the frequency band of the sound output from mid-frequency speaker 32A and the frequency of the sound output from low-frequency speaker 31 deteriorates, thus causing problems with sound quality. Even if the cutoff frequency of filter 112 is set to approximately the same value as the cutoff frequency of filter 111, resistors 121 and 122 in speaker system 1A are provided to prevent the aforementioned overcurrent. Figure 11 This is a graph illustrating an example of the frequency response of the impedance of loudspeaker system 1A. Figure 10 In the example shown, the impedance in the 200–500 Hz frequency band is sufficiently high compared to the impedance of the low-frequency speaker 31 or the mid-frequency speaker 32A, which is 4 Ω. Therefore, the overcurrent flowing through the amplifier 2 in this frequency band is reduced.
[0043] Figure 12 This is a diagram illustrating an example of the sound pressure level measurements for each frequency of sound played through speaker system 1A inside vehicle C. Furthermore, Figure 12The curve GW shows the measurement results for the playback sound of the low-frequency speaker 31 unit. Figure 12 The GS curve shows the measurement results for the playback sound of the 32A mid-range loudspeaker unit. Figure 12 The medium curve GT shows the measurement results for the playback sound of the high-frequency loudspeaker 33 unit. Figure 12 Curves GA1 and GA2 show the measurement results for the sound obtained by superimposing the playback sounds of the low-frequency speaker 31, the mid-frequency speaker 32A, and the high-frequency speaker 33. More specifically, curve GA1 shows the measurement results when the playback sounds of the low-frequency speaker 31 and the mid-frequency speaker 32A are in phase, and curve GA2 shows the measurement results when the playback sounds of the low-frequency speaker 31 and the mid-frequency speaker 32A are out of phase. (Reference) Figure 12 As shown by curves GA1 and GA2, there are no frequency bands with a significant drop in sound pressure in the playback sound played by speaker system 1A, and therefore the sound quality in a specific frequency band is not significantly degraded.
[0044] The speaker system 1A according to this embodiment reduces the downward shift of the sound image obtained from the playback sound from the intermediate frequency speaker 32A. Furthermore, the speaker system 1A according to this embodiment allows for the construction of a three-way speaker system using fewer components than conventional speaker systems. Additionally, according to this embodiment, sound quality degradation caused by a deterioration in the connection between the frequency band of the sound output from the intermediate frequency speaker 32A and the frequency band of the sound output from the low frequency speaker 31 is avoided, and the occurrence of overcurrent in the amplification device 2 is reduced.
[0045] B. Deformation
[0046] The above-described implementation methods can be modified as follows.
[0047] (1) The filter 112 in the loudspeaker system 1A is a high-pass filter, but the filter 112 can also be a band-pass filter. However, since the band-pass filter is constructed by connecting the high-pass filter and the low-pass filter in series, using the high-pass filter as the filter 112 in this embodiment reduces the number of components constituting the loudspeaker system 1A compared to using the band-pass filter as the filter 112.
[0048] (2) Both filters 112 and 113 in the loudspeaker system 1A are first-order filters, but either or both of filters 112 and 113 can also be second-order filters. However, since a second-order filter is composed of more components than a first-order filter, by using both filters 112 and 113 as first-order filters as in this embodiment, the number of components constituting the loudspeaker system 1A can be reduced compared to using either or both of filters 112 and 113 as second-order filters.
[0049] (3) In loudspeaker system 1A, by setting resistors 121 and 122, the occurrence of overcurrent caused by setting the cutoff frequency of filter 112 to be equal to the cutoff frequency of filter 111 is reduced. However, if the impedance of the intermediate frequency loudspeaker 32A is high, resistor 122 is not needed. Furthermore, if the DC resistance component of the voice coil in the low-frequency loudspeaker 31 also serves the function of resistor 121, then resistor 121 is not needed. That is, resistors 121 and 122 can be omitted. For example, as... Figure 13 The difference between speaker system 1B and speaker system 1A is that speaker system 1B lacks resistors 121 and 122, and a mid-range speaker 32B is used instead of mid-range speaker 32A. The impedance of mid-range speaker 32B is higher than that of a typical speaker, specifically adjusted to 5Ω. In speaker system 1B, the DC resistance component of the voice coil in low-frequency speaker 31 functions as resistor 121.
[0050] (4) Speaker system 1A and speaker system 1B are examples of applications of the present invention for a three-channel vehicle speaker system. However, the application of the present invention is not limited to a three-channel vehicle speaker system; the present invention can also be applied to a two-channel vehicle speaker system. Figure 14 This diagram illustrates a structural example of a loudspeaker system 1C, which is an application example of the present invention of a two-way vehicle loudspeaker system consisting of a low-frequency loudspeaker 31 and a mid-frequency loudspeaker 32. Figure 14 and Figure 13 By comparison, it becomes clear that loudspeaker system 1C differs from loudspeaker system 1B in the following two ways. The first difference is that loudspeaker system 1C does not include a tweeter 33. The second difference is that loudspeaker system 1C has a channel splitting network 10C instead of channel splitting network 10B. The channel splitting network 10C differs from channel splitting network 1B in that channel splitting network 10C does not have a filter 113.
[0051] In the above embodiment, the low-frequency speaker 31 is located in the front door D of the vehicle C, closer to the driver's seat than the passenger seat, but it can also be located between the console CS and the floor F, or in the trunk TR of the vehicle C. Additionally, the mid-frequency speaker 32A can also be located on the pillar P of the vehicle C. The pillar P is the pillar connecting the roof, i.e., the roof, and the vehicle body. In short, the mid-frequency speaker 32A can be located above the low-frequency speaker 31 on the vertical axis Z.
[0052] C. The methods that can be grasped from various implementation methods and variations
[0053] This invention is not limited to the above-described embodiments and variations, and can be implemented in various ways without departing from its spirit. For example, this invention can also be implemented in the following ways. In order to solve some or all of the problems of this invention, or to achieve some or all of the effects of this invention, the technical features corresponding to the technical features in the embodiments described below can be appropriately replaced or combined. In addition, if a technical feature is not described as essential in this specification, it can be appropriately deleted.
[0054] One aspect of the present invention relates to a loudspeaker system 1A having a low-frequency loudspeaker 31, an intermediate-frequency loudspeaker 32A, a filter 111, and a filter 112. The low-frequency loudspeaker 31 and the intermediate-frequency loudspeaker 32A are disposed in a vehicle C equipped with the loudspeaker system 1A. The low-frequency loudspeaker 31 is an example of a first loudspeaker in the present invention. The intermediate-frequency loudspeaker 32A is located above the low-frequency loudspeaker 31 on the vertical axis Z along the vertical direction. The intermediate-frequency loudspeaker 32A is an example of a second loudspeaker in the present invention. The filter 111 is a low-pass filter. The filter 111 is disposed between the output terminal 20 of the amplification device 2 that outputs the sound signal Sin and the low-frequency loudspeaker 31. The filter 111 and the low-frequency loudspeaker 31 constitute an output system SL1. The filter 111 is an example of a first filter in the present invention. The output system SL1 is an example of a first output system in the present invention. The filter 112 is a high-pass filter or a band-pass filter. The filter 112 is disposed between the output terminal 20 and the intermediate-frequency loudspeaker 32A. Filter 112 and intermediate frequency speaker 32A constitute output system SL2. Filter 112 is an example of a second filter in this invention. Output system SL2 is an example of a second output system in this invention. In this speaker system 1A, the crossover frequency between the frequency responses of output system SL1 and output system SL2 is below 300Hz. According to speaker system 1A, while avoiding sound quality degradation of the playback sound played through low-frequency speaker 31 and intermediate frequency speaker 32A, the downward shift of the sound image obtained from the playback sound from intermediate frequency speaker 32A is reduced. Furthermore, low-frequency speaker 31 can be disposed in the door of vehicle C, between the console and the floor, or in the trunk, and intermediate frequency speaker 32A can be disposed in the door of vehicle C or the pillar of vehicle C.
[0055] Filter 112 is preferably a high-pass filter. If filter 112 is a high-pass filter, the number of components constituting the loudspeaker system 1A can be reduced compared to the case where filter 112 is a band-pass filter.
[0056] The loudspeaker system 1A may include a high-frequency loudspeaker 33 and a filter 113 disposed between the output terminal 20 and the high-frequency loudspeaker 33, the filter 113 preferably being a high-pass filter. According to this method, the downward shift of the sound image position can be reduced, and a three-way loudspeaker system can be constructed with fewer components than existing loudspeaker systems. The high-frequency loudspeaker 33 is an example of a third loudspeaker in this invention. The filter 113 is an example of a third filter in this invention.
[0057] Preferably, at least one of filter 112 and filter 113 is a first-order filter. This method reduces the number of components constituting the loudspeaker system 1A compared to a method where both filter 112 and filter 113 are second-order filters.
[0058] The loudspeaker system 1A may further include at least one of a resistor 121 connected in series between the filter 111 and the low-frequency speaker 31, and a resistor 122 connected in series between the filter 112 and the mid-frequency speaker 32A. Resistor 121 is an example of a first resistor in this invention. Resistor 122 is an example of a second resistor in this invention. According to this method, overcurrent flowing through the amplifier 2 can be prevented because the crossover frequency between the frequency responses of the output system SL1 and the output system SL2 is less than 300Hz.
[0059] The intermediate frequency speaker 32A can be replaced by an intermediate frequency speaker 32B with an impedance exceeding 5Ω. In this case, it is possible to prevent overcurrent from flowing through the amplifier 2 due to the crossover frequency between the frequency responses of the output system SL1 and the output system SL2 being below 300Hz.
[0060] Explanation of the label
[0061] 1A, 1B, 1C, 1D, 1E... loudspeaker system; 10A, 10B, 10C, 10D, 10E... channel splitting network; 111, 112, 113... filters; 121, 122... resistors; 2... amplifier; 20... output terminal; 31... low-frequency loudspeaker; 32A, 32B... mid-frequency loudspeaker; 33... high-frequency loudspeaker.
Claims
1. A loudspeaker system comprising: The first speaker, which is located in the vehicle, is responsible for playing low-frequency sounds; The second speaker, which is disposed in the vehicle and located above the first speaker on the vertical axis along the vertical direction, is responsible for playing mid-frequency sounds; A first filter is disposed between the output terminal of the amplification device that outputs the sound signal and the first speaker; as well as A second filter is disposed between the output terminal and the second speaker. The first filter is a second-order low-pass filter; The second filter is a high-pass filter or a band-pass filter; The crossover frequency between the frequency response of the first output system, which includes the first filter and the first speaker, and the frequency response of the second output system, which includes the second filter and the second speaker, is below 300 Hz.
2. The loudspeaker system according to claim 1, comprising: The third speaker; and A third filter is disposed between the output terminal and the third speaker. The third filter is a high-pass filter.
3. The loudspeaker system according to claim 2, wherein, At least one of the second filter and the third filter is a first-order filter.
4. The loudspeaker system according to any one of claims 1 to 3, wherein, It also has at least one of a first resistor and a second resistor. The first resistor is connected in series between the first filter and the first speaker, and the second resistor is connected in series between the second filter and the second speaker.
5. The loudspeaker system according to any one of claims 1 to 3, wherein, The impedance of the second speaker is 5Ω or higher.
6. The loudspeaker system according to any one of claims 1 to 3, wherein, The first speaker is located between the vehicle's doors, console, and floor, or in the trunk. The second speaker is disposed in the door or the pillar of the vehicle.