JPH0799698A - Speaker system - Google Patents

Abstract

PURPOSE:To provide a speaker system capable of performing feedback using a bridge circuit over a wide band. CONSTITUTION:This system is provided with a cabinet 12, a speaker unit 11 attached to the cabinet 12, a power amplifier 13 for driving the speaker unit 11, the bridge circuit 14 in which a voice coil impedance correction circuit 17 composed of a resistor Rs and a capacitor Cs for detecting a voltage proportional to the vibration system speed of the speaker unit 11 is arranged parallelly to the speaker unit 11 and a feedback circuit 15 for transforming the detection voltage of the bridge circuit 14 and then feeding it back as it is or through a differentiation circuit to the power amplifier 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker system having a feedback circuit for improving bass reproduction capability.

[0002]

2. Description of the Related Art In recent years, with the digitization of audio output devices, it has been desired in recent years to expand the reproduction band of high sound quality, high output, and low sound range. Conventionally, a speaker system equipped with a feedback circuit is often used. It was being done.

A Kelton type speaker system having a conventional feedback circuit will be described below with reference to FIG.

As shown in FIG. 10, a Kelton type cabinet 2 having a port 7 (the inside of the cabinet is formed by a cavity dividing member 2c and a cavity 2a and a cavity 2b).
And a speaker unit 1 is attached to the cavity dividing member 2c, and a voltage proportional to the vibration system speed of the speaker unit 1 attached to a passive radiator or a cabinet in which a port 7 is attached to an opening of the cabinet is applied. , A feedback circuit 5 that detects a voltage by the bridge circuit 4 having the speaker unit 1 as one side and transforms the detected voltage as it is or feeds back negatively to a power amplifier 3 for driving the speaker unit 1 through a differentiating circuit. ing.

[0005]

However, in the above-mentioned conventional structure, when the voltage detected by the bridge circuit 4 is transformed and returned as it is or through the differentiating circuit, the electric impedance of the speaker unit is the voice of the speaker unit. It has a curve that gradually rises from the mid-high range (around 400 Hz) due to the coil inductance, and affects the rise in voltage detected by the bridge circuit and the phase rotation. At this time, particularly when the voice coil inductance of the speaker unit 1 is large, it is not possible to control the rise in the mid-high range of the electric impedance, and when the detected voltage detected by the bridge circuit 4 is fed back to the power amplifier. There is a problem that it becomes a positive feedback and causes the power amplifier to oscillate, and it becomes impossible to apply feedback using a bridge circuit over a wide band.

SUMMARY OF THE INVENTION The first object of the present invention is to provide a speaker system capable of feedback using a bridge circuit over a wide band in order to solve the above-mentioned conventional problems.

A second object is to provide a speaker system capable of feedback using a bridge circuit over a wide band by using a plurality of speaker units having different reproduction bands.

A third object of the present invention is to provide a speaker system in which the bass reproduction limit frequency is made lower than that in the case where a closed cabinet is used and feedback can be performed using a bridge circuit over a wide band.

A fourth object is to lower the bass reproduction limit frequency as compared with the case where a closed cabinet is used, and by using a plurality of speaker units having different reproduction bands,
An object of the present invention is to provide a speaker system capable of feedback using a bridge circuit over a wide band.

A fifth object of the present invention is to provide a speaker system for low frequency reproduction, which can perform feedback using a bridge circuit which does not require a low pass filter.

A sixth object is to provide a speaker system capable of feedback by using a bridge circuit over a wide band by combining a speaker unit for low tone reproduction and a speaker unit having a reproduction band higher than that.

[0012]

In order to achieve the first object, the speaker system of the present invention is such that the cabinet is hermetically sealed except for the sound pressure radiating section, and the speaker circuit has a bridge circuit having one side. A voice coil impedance correction circuit consisting of a resistor and a capacitor is arranged in parallel with the speaker unit, and a feedback circuit for feeding back to the power amplifier driving the speaker unit as it is after transforming the detection voltage of the bridge circuit or through a differentiation circuit is provided. It has a configuration provided (first configuration).

In order to achieve the second object, the speaker system of the present invention has a structure in which speaker units having different reproduction bands are connected in parallel to the speaker unit in addition to the structure of the first speaker system. (Second configuration).

In order to achieve the third object, the speaker system of the present invention has a structure (third structure) in which a passive radiator or a port is attached to a cabinet in addition to the structure of the first speaker system. Have

Further, in order to achieve the above-mentioned fourth object, the speaker system of the present invention is different from that of the above-mentioned first speaker system in that a passive radiator or a port is attached to a cabinet and the speaker unit is different in parallel. This is a configuration in which a speaker unit having a reproduction band is connected (fourth configuration).

In order to achieve the fifth object, the speaker system of the present invention has the same configuration as the first speaker system except the cabinet,
The inside of the cabinet is divided into a cavity 1 and a cavity 2 by a cavity dividing member, the speaker unit is attached to the cavity dividing member, and a structure using a Kelton type cabinet in which a passive radiator or a port is attached to an opening of the cabinet. (Fifth configuration).

Further, in order to achieve the sixth object, the speaker system of the present invention has the same structure as the first speaker system except the cabinet and the speaker unit, but the inside of the cabinet is formed by a cavity dividing member. The speaker unit is divided into a cavity 1 and a cavity 2, the speaker unit is attached to the cavity dividing member, and a Kelton type cabinet in which a passive radiator or a port is attached to the opening of the cabinet is used, and different from the speaker unit in parallel. It is a configuration (sixth configuration) in which a speaker unit having a reproduction band is connected.

[0018]

In the first structure described above, the voice coil inductance of the speaker unit of the bridge circuit having the speaker unit as one side causes the mid-high range (400 Hz).
The gradual increase in the electrical impedance from (in the vicinity) is flattened by the resistor and the capacitor arranged in parallel with the speaker unit, and the increase in the voltage detected by the bridge circuit and the phase rotation are suppressed over a wide band. This allows
The speaker unit can be subjected to speed-type feedback by detecting a voltage proportional to the vibration system speed of the speaker unit and acceleration-type feedback through a differentiating circuit. At this time, the velocity feedback is applied in the direction of keeping the vibration system velocity of the speaker unit constant, and has a function equivalent to strengthening the magnetic circuit of the speaker unit. Further, the acceleration type feedback is applied in the direction in which the vibration system acceleration of the speaker unit is made constant, and has a function equivalent to making the vibration system mass of the speaker unit heavy. Therefore, the above velocity type feedback,
By applying acceleration type feedback together, a flat sound pressure frequency characteristic can be obtained over a wide band and ultra-low range.

Further, in the above-mentioned second structure, the reproduction band can be expanded by using a plurality of speaker units having different reproduction bands.

Further, in the third configuration, part of the sound radiated from the rear surface of the speaker unit is radiated together with the sound radiated from the front surface of the speaker unit through the passive radiator or the port so that the bass reproduction sound pressure is reduced. To reinforce.

In the fourth structure, a part of the sound radiated from the rear surface of the speaker unit is radiated together with the sound radiated from the front surface of the speaker unit through the passive radiator or the port so that the bass reproduction sound pressure is reduced. In addition to increasing the reproduction frequency, the reproduction band can be expanded by using a plurality of speaker units having different reproduction bands.

In the fifth structure, the sound emitted from the speaker unit propagates inside the cavity 1,
It is radiated from the passive radiator or port that is the opening. At this time, due to the resonance of the air compliance components in the cavities 1 and 2 and the vibration system mass component of the speaker unit and the passive radiator or port, the bandpass type acoustic filter of about 12 dB / oct is applied.

Further, in the sixth structure, the sound radiated from the speaker unit propagates inside the cavity 1 and is radiated from the passive radiator or port which is the opening. At this time, cavity 1 and cavity 2
Resonance of the air compliance component in the cavity of the speaker unit and the vibration system mass component of the speaker unit and the passive radiator or port puts the bandpass type acoustic filter of about 12 dB / oct into the state in which it is in addition to the state in which a plurality of different reproduction bands are provided. The reproduction band can be expanded by using the speaker unit.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. 11
Is a speaker unit having an effective vibration radius of 65 mm, an effective vibration mass of 12.5 g, a direct current resistance of 5.1Ω, and a minimum resonance frequency of 40 Hz and a diameter of 17 cm. The speaker unit 11 is attached to a cabinet 12 which is closed except for the portion where the speaker unit 11 is attached, and the internal volume is 13.8 liters. The speaker unit 11 is driven by the power amplifier 13, and R1 =
56KΩ, R2 = 1.6KΩ, R3 = 0.1Ω, and the bridge circuit 14 with the speaker unit 1 as one side, and the impedance correction circuit 17 with Rs = 27Ω and Cs = 27μF in parallel with the speaker unit 11 are inserted. There is.
16 is a signal source.

The detected voltage from the bridge circuit 14 is directly proportional to the speed of the vibration system of the speaker unit 11, and the feedback circuit 15 transforms the detected voltage as it is and the one transformed through the differentiating circuit. They are combined and fed back to the power amplifier 13. At this time, a voltage proportional to the vibration system acceleration is obtained by passing the differential circuit once. In addition, the impedance correction circuit 17 arranged in parallel with the speaker unit 11 controls the mid-high range (400H) due to the voice coil inductance of the speaker unit 11.
The gradual increase in the electrical impedance from (around z) is flattened, and the increase in the voltage detected by the bridge circuit 14 and the phase rotation are suppressed. Thereby, when the detected voltage is fed back from the feedback circuit 15 to the power amplifier 13, the detected voltage becomes positive feedback and the power amplifier 13 is prevented from oscillating.

In the speaker system configured as described above, MFB (motional feedback) is applied to the speaker unit 11, and the electromagnetic braking resistance of the speaker unit 11 (= (magnetic flux density × effective conductor length) ² / DC resistance) The effective oscillating mass can be made very large equivalently,
The bass reproduction limit frequency can be lowered. FIG. 2 shows the sound pressure frequency characteristics of the speaker system having the above configuration. a
Is the characteristic before feedback is applied, b is the characteristic after feedback is applied,
In c, the sound pressure of 200 Hz or higher in b is raised according to the sound pressure of 200 Hz or higher in a, and it can be seen that the bass reproduction band is lower by 1 oct or more than before the feedback is applied.

Next, a second embodiment of the present invention will be described with reference to FIG.
Will be explained. It is the same as the first embodiment except the cabinet 22 and speaker units 28a and 28b. The cabinet 22 includes a speaker unit 21 and two speaker units 28a and 28b having a reproduction band different from that of the speaker unit 21.
The speaker unit 28b has a structure of y and is connected in parallel to the speaker unit 21 via the capacitor C. The capacitor C is a high-pass filter of the speaker unit 28b and determines the cross frequency with the reproduction band of the speaker unit 21.

Next, a third embodiment of the present invention will be described with reference to FIG.
Will be explained. It is the same as the first embodiment except for the cabinet 32. The cabinet 32 includes a passive radiator 38 in addition to the speaker unit 31. The passive radiator 38 causes a part of the sound radiated from the back surface of the speaker unit 31 to pass through the passive radiator 38 in phase with the sound radiated from the front surface of the speaker unit 31, thereby enhancing the bass reproduction sound pressure. To do. With this configuration, the reproduction limit frequency can be lowered as compared with the first embodiment. FIG. 5 shows the sound pressure frequency characteristics of the speaker system having this configuration. a is a characteristic before feedback is applied, b is a characteristic after feedback is applied, and c is 2 of b.
It is understood that the sound pressure of 00 Hz or more is raised according to the sound pressure of 200 Hz or more of a, and the bass reproduction band is lower by about 1 oct than that before the feedback is applied. The amount by which the sound pressure is increased at this time is smaller than that in the first embodiment, and the superiority of the low sound range due to the structure of the cabinet 32 is shown (however, the frequencies below 40 Hz are excluded). In this embodiment, the part that radiates a part of the sound radiated from the back surface of the speaker unit 31 is the passive radiator, but this may be a port.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
Will be explained. It is the same as the first embodiment except for the cabinet 42, the passive radiator 48 and the speaker units 49a and 49b. Cabinet 42
In addition to the speaker unit 41, two speaker units 49a having a reproduction band different from that of the speaker unit 41,
The speaker unit 49b is connected in parallel to the speaker unit 41 via the capacitor C, and has a 3-way structure in which 49b is attached. The capacitor C is a high-pass filter of the speaker unit 49b and determines the cross frequency with the reproduction band of the speaker unit 41. In this embodiment, the portion that radiates a part of the sound radiated from the back surface of the speaker unit 41 is the passive radiator 48, but this may be a port. Also,
In FIG. 6, the passive radiator 48 is connected to the speaker unit 4
Although it was attached to the back of No. 1, it is not limited to the back.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
Will be explained. It is the same as the first embodiment except for the cabinet 52. The interior of the cabinet 52 has a cavity 5 with a cavity dividing member 52c.
2a and the cavity 52b are divided, the speaker unit 51 is attached to the cavity dividing member 52c, and the passive radiator 5 is provided in the opening of the cabinet 52.
Eight. In this configuration, the speaker unit 51
Sound radiated from propagates inside the cavity 52a,
The bandpass type acoustic filter of about 12 dB / oct is applied by the resonance of the air compliance component in the cavities 52a and 52b and the vibration system mass component of the speaker unit 51 and the passive radiator 58, which is radiated from the passive radiator 58 which is the opening. It will be in a state of being. FIG. 8 shows the sound pressure frequency characteristics of the speaker system having this configuration. a is a characteristic before feedback is applied, b is a characteristic after feedback is applied, and 1 oc is obtained by applying feedback.
It can be seen that the characteristics are flat over t or more. In this embodiment, the portion from which sound is radiated is a passive radiator, but this may be a port.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
Will be explained. It is the same as the first embodiment except for the cabinet 62, the passive radiator 68 and the speaker units 69a and 69b. The cabinet 62 is
In addition to the speaker unit 61, two speaker units 69a having a reproduction band different from that of the speaker unit 61,
The speaker unit 69b has a three-way structure with the 69b attached, and the speaker unit 69b is connected in parallel to the speaker unit 61 via a capacitor. This capacitor is a high-pass filter of the speaker unit 69b and determines the cross frequency with the reproduction band of the speaker unit 61.
In this embodiment, the portion from which sound is radiated is a passive radiator, but this may be a port.

[0033]

As described above, in the speaker system of the present invention, since the voice coil impedance correction circuit composed of the resistor and the capacitor is arranged in parallel in the speaker unit which is one side of the bridge circuit, the voice coil inductance of the speaker unit causes It is possible to suppress the rise of the detection voltage and the phase rotation and to perform power amplification using a bridge circuit over a wide band. Moreover, since a plurality of speaker units having different reproduction bands are used, the reproduction band can be expanded. In addition, since the phase inversion type cabinet composed of the speaker unit and the passive radiator or port is used, the bass reproduction sound pressure can be enhanced. Further, since the Kelton type cabinet composed of the speaker unit and the passive radiator or the port is used, the band pass type acoustic filter can be applied.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a speaker system according to a first embodiment of the present invention.

FIG. 2 is a sound pressure frequency characteristic diagram of the speaker system of the first embodiment.

FIG. 3 is a block diagram showing a configuration of a speaker system according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a speaker system according to a third embodiment of the present invention.

FIG. 5 is a sound pressure frequency characteristic diagram of the speaker system of the third embodiment.

FIG. 6 is a block diagram showing a configuration of a speaker system according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a speaker system according to a fifth embodiment of the present invention.

FIG. 8 is a sound pressure frequency characteristic diagram of the speaker system of the fifth embodiment.

FIG. 9 is a block diagram showing the configuration of a speaker system according to a sixth embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a Kelton type speaker system using a conventional bridge circuit.

[Explanation of symbols]

1, 11, 21, 31, 41, 51, 61 Speaker unit 2, 12, 22, 32, 42, 52, 62 Cabinet 2a, 52a, 62a Cavity 12b, 52b, 62b Cavity 2c, 52c, 62c Cavity division Member 3,13,23,33,43,53,63 Power amplifier 4,14,24,34,44,54,64 Bridge circuit 5,15,25,35,45,55,65 Feedback circuit 6,16, 26, 36, 46, 56, 66 Signal source 7 port 17, 27, 37, 47, 57, 67 Impedance correction circuit 28a, 28b, 49a, 49b, 69a, 69b Mid-high range speaker unit 38, 48, 58, 68 Passive radiator

Claims (6)

[Claims] 1. A cabinet hermetically sealed except for a sound pressure radiating section, a speaker unit attached to the cabinet, a power amplifier for driving the speaker unit, and a voltage proportional to a vibration system speed of the speaker unit. A bridge circuit in which a voice coil impedance correction circuit composed of a resistor and a capacitor is arranged in parallel with the speaker unit, and a feedback circuit that feeds back the voltage detected by the bridge circuit to the power amplifier as it is or through a differentiation circuit. A speaker system comprising: 2. A cabinet hermetically sealed except for a sound pressure radiating section, a plurality of speaker units attached to the cabinet and having different reproduction bands, a power amplifier for driving the speaker unit, and a vibration system of the speaker unit. A bridge circuit in which a voice coil impedance correction circuit composed of a resistor and a capacitor for detecting a voltage proportional to the speed is arranged in parallel with the speaker unit, and the detection voltage of the bridge circuit is transformed, or as it is, or through a differentiating circuit. A speaker system comprising a feedback circuit for feeding back to a power amplifier. 3. A phase inversion type cabinet composed of a speaker unit and a passive radiator or a port, a power amplifier for driving the speaker unit, and a resistor for detecting a voltage proportional to a vibration system speed of the speaker unit. A bridge circuit in which a voice coil impedance correction circuit composed of a capacitor and a capacitor is arranged in parallel with the speaker unit; and a feedback circuit that feeds back the voltage detected by the bridge circuit to the power amplifier as it is or through a differentiating circuit. A speaker system characterized by the above. 4. A phase inversion type cabinet comprising a plurality of speaker units having different reproduction bands and a passive radiator or a port, a power amplifier for driving the speaker unit, and a vibration system speed of the speaker unit. A bridge circuit in which a voice coil impedance correction circuit composed of a resistor and a capacitor for detecting the voltage is arranged in parallel with the speaker unit, and the voltage detected by the bridge circuit is transformed, as it is, or through a differentiation circuit to the power amplifier. A speaker system comprising a feedback circuit for returning. 5. A Kelton type cabinet composed of a speaker unit and a passive radiator or port, a power amplifier for driving the speaker unit, and a resistor for detecting a voltage proportional to the vibration system speed of the speaker unit. A voice coil impedance correction circuit composed of a capacitor arranged in parallel with the speaker unit; and a feedback circuit for returning the voltage detected by the bridge circuit to the power amplifier as it is or through a differentiating circuit. Speaker system characterized by. 6. A Kelton type cabinet composed of a plurality of speaker units having different reproduction bands and a passive radiator or port, a power amplifier for driving the speaker unit, and a vibration system speed proportional to the speaker unit. A bridge circuit in which a voice coil impedance correction circuit composed of a resistor and a capacitor for detecting a voltage is arranged in parallel with the speaker unit, and the detection voltage of the bridge circuit is transformed and then fed back to the power amplifier as it is or through a differentiation circuit. And a feedback circuit for controlling the speaker system.