close

Вход

Забыли?

вход по аккаунту

?

JPH05183978

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH05183978
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
motional feedback (hereinafter referred to as "MFB") speaker apparatus provided with a passive
radiator in order to improve bass reproduction capability.
[0002]
2. Description of the Related Art In recent years, it has been desired to improve characteristics
such as high sound quality, high output, and expansion of a bass region with the digitization of
audio output equipment in the speaker device, and an MFB speaker device is conventionally used
for this application. ing. Hereinafter, a conventional MFB speaker device will be described.
[0003]
FIG. 4 is a block diagram showing an example of a conventional MFB speaker device. As shown in
the figure, an audio signal from an audio input signal source 1 is amplified by a power amplifier
2 and given to a phase inversion type speaker 3. The phase inversion type speaker 3 has a
speaker unit 5 and a bass reflex port 6 opened at the lower part of the mounting surface in the
phase inversion cabinet 4, and is a speaker capable of reproducing bass with a relatively small
internal volume. The bass reflex port 6 emits the phase-reversed sound radiated from the rear
surface of the diaphragm of the speaker unit 5 to emphasize the bass range.
08-05-2019
1
[0004]
A detector 7 is attached to the dust cap of the diaphragm of the speaker unit 5. The detector 7 is
a sensor that detects the vibration acceleration of the speaker unit 5 and converts it into a
voltage, and the output thereof is given to the feedback circuit 8. If the detector 7 detects, for
example, the velocity of the diaphragm of the speaker unit 5, the feedback circuit 8 generates a
velocity signal, an acceleration signal obtained by differentiating the velocity signal, and a
position signal (amplitude) obtained by integrating the velocity signal. And a circuit that changes
the gain and phase of these signals to output a feedback signal. The output of the feedback
circuit 8 is provided to the power amplifier 2 as a negative feedback signal.
[0005]
In the MFB speaker apparatus having such a configuration, the amplitude and phase of the audio
signal input to the power amplifier 2 are controlled so that resonance or anti-resonance is
suppressed at each specific portion of the reproduction frequency, and the reproduction
characteristics in the low band portion While compensating for the distortion of the high
frequency part. FIG. 5 is a diagram showing the frequency characteristic of the speaker unit 5
alone and the resonance frequency characteristic of the bass reflex port 6. The curve A shows the
frequency characteristic of the speaker unit 5 itself, and the vibration drops sharply around 50
Hz. Curve B shows the resonance frequency characteristic of the cabinet 4 having the bass reflex
port 6 and has a resonance peak near 50 Hz.
[0006]
However, in such a conventional configuration, the air vibration in front of the speaker unit 5 can
be detected by the detector 7 attached to the diaphragm of the speaker unit 5, but from the bass
reflex port 6 The emitted air vibration could not be detected. Therefore, when MFB is applied to
the phase inversion type speaker 3 composed of the speaker unit 5 having the frequency
characteristic as shown in FIG. 5 and the bass reflex port 6, the phase of the speaker unit 5
becomes unstable at the antiresonance frequency (around 50 Hz). Become. That is, when a
feedback signal is generated by the feedback circuit 8 by the output of the detector 7, the
feedback signal may be in the same phase where it should be in the opposite phase at the input
of the power amplifier 2. This causes a problem that MFB control in the vicinity of this frequency
08-05-2019
2
becomes unstable. Furthermore, there is also a problem that distorted sound such as wind noise
from the bass reflex port 6 is generated.
[0007]
The present invention has been made in view of such conventional problems, and in the phase
inversion type speaker, the antiresonance frequency of the speaker unit 5 when the MFB is not
applied matches the resonance frequency of the bass reflex port 6 However, it is an object of the
present invention to realize an MFB speaker device which can stably apply MFB and is excellent
in low frequency characteristics with little distorted sound.
[0008]
According to a first aspect of the present invention, there is provided a baffle plate for dividing
an interior of a cabinet into first and second spaces, and a baffle plate having openings in the
first space. A speaker unit that emits air vibration to the divided second space, a speaker having a
passive radiator at the front opening of the second space of the cabinet, and low frequency
characteristics of the audio output of the input signal source corrected Characteristic correction
circuit, a power amplifier for amplifying the power of the output of the characteristic correction
circuit to drive the speaker unit, a detector attached to the diaphragm of the passive radiator to
detect its vibration, and the amplitude of the output signal of the detector And a feedback circuit
that generates a feedback signal based on the phase and provides the feedback signal to the
power amplifier.
[0009]
The invention of claim 2 of the present application relates to a baffle plate that divides the
interior of the cabinet into first and second spaces, and a second space that is attached to the
opening of the baffle plate in the first space and divided. Speaker unit for radiating air vibration,
speaker having passive radiator at front opening of second space of cabinet, characteristic
correction circuit for correcting low frequency characteristics of audio output of input signal
source, characteristic correction circuit Power amplifier for driving the speaker unit by power
amplification of the output of the speaker, a first detector and a second detector attached to the
diaphragm of the speaker unit and the passive radiator to detect the vibration thereof, and a first
detection Based on the amplitude and phase of the output signal of the second detector, and
generating a feedback signal based on the amplitude and phase of the output signal of the There
generates a feedback signal, is characterized in that it comprises a second feedback circuit
providing a power amplifier of the feedback signal.
[0010]
08-05-2019
3
According to the present invention having such a feature, the sound signal from the input signal
source is corrected by the characteristic correction circuit for the sound pressure in the low
frequency range, and is applied to the power amplification circuit.
When the power amplification circuit drives the speaker unit, the detector detects the vibration
of the diaphragm of the speaker unit or passive radiator.
The feedback circuit then generates a feedback signal based on the amplitude and phase of the
detector output signal and provides it to the power amplifier.
The feedback signal output from the feedback circuit and the original audio signal are
synthesized, and the power amplifier outputs a drive signal corrected for the bass range to the
speaker unit. Next, the sound pressure radiated from the speaker unit is output to the outside
through the passive radiator. As a result, the bass reproduction limit frequency of the speaker is
expanded, and feedback is applied to the harmonic components, so that the harmonic distortion
is also reduced in the high-tone reproduction frequency band.
[0011]
The first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of an MFB speaker apparatus according to a
first embodiment of the present invention. In the figure, the input signal source 1, the power
amplifier 2 and the speaker unit 5 are the same as those in the prior art. A characteristic
correction circuit 9 is provided between the input signal source 1 and the power amplifier 2. The
characteristic correction circuit 9 corrects the frequency characteristic of the audio input signal,
and in particular is a circuit for emphasizing the audio signal in the low frequency band shown in
FIG.
[0012]
Unlike the prior art, the speaker 10 is divided into upper and lower first and second spaces by
the baffle plate 11a. The central portion of the baffle plate 11a is opened, and the speaker unit 5
08-05-2019
4
is mounted in the lower second space so that air vibration can be radiated from the opening to
the upper first space. Also, a passive radiator 12 is attached to the front opening of the upper
space of the cabinet 11. The passive radiator 12 is a diaphragm having no drive coil, converts air
vibration in the upper space into a reciprocating motion of a flat plate, and radiates the sound
pressure to the outside by a wide-area vibrating flat plate. A detector 13 is attached to the
diaphragm of the passive radiator 12. The detector 13 detects the vibration acceleration of the
diaphragm, and its output is given to the feedback circuit 14.
[0013]
The feedback circuit 14 generates an acceleration signal output from the detector 13, a velocity
signal obtained by integrating the acceleration signal, and a position signal (amplitude) obtained
by further integrating the velocity signal, as in the feedback circuit 8 shown in FIG. It is a circuit
that changes the gain and phase to output a feedback signal. The output of the feedback circuit
14 is provided to the power amplifier 2 as a negative feedback signal.
[0014]
In the MFB speaker apparatus having such a configuration, the difference in the frequency
characteristic of the phase inversion type speaker 10 according to the presence or absence of the
feedback of the signal of the detector 13 attached to the passive radiator 12 is shown in FIG.
Curve C shows the frequency characteristics when the MFB of the MFB speaker 10 is not applied.
A curve D shows the frequency characteristics when MFB is applied without using the
characteristic correction circuit 9, and a curve E shows frequency characteristics when MFB is
applied using the characteristic correction circuit 9.
[0015]
When MFB feedback is not applied, a peak occurs in the frequency band of 30 to 50 Hz as shown
by curve C, but when feedback is applied, it is flat at an ultra low frequency band of 30 to 80 Hz
as shown by curve D. Sound pressure characteristics can be obtained. This is because the
acceleration of the diaphragm of the speaker unit 5 and the passive radiator 12 is controlled to
be constant by negatively feedbacking the acceleration of the passive radiator 12 to the power
amplifier 2 of FIG. That is, as the effective vibration mass of the passive radiator 12 is increased,
the reproduction limit of the speaker for reproducing the low frequency sound is expanded.
08-05-2019
5
Further, by inputting the audio signal of the input signal source 1 to the characteristic correction
circuit 9, it is understood that the gain is increased by 5 db or more in the low range of 30 to
100 Hz as shown by the curve E.
[0016]
As described above, according to the present embodiment, by applying the MFB, the bass
reproduction limit frequency of the speaker is expanded and the sound pressure level is also
increased, and the harmonic component is also fed back, so that the harmonic distortion in the
high sound reproduction area is also It can be reduced. Also, by using a passive radiator instead
of the bass reflex port, not only distortion noise such as wind noise generated from the bass
reflex port is eliminated, but also sound waves can be emitted from a wider cross-sectional area
compared with the bass reflex port. You can get a bass with a sense of volume.
[0017]
Next, an MFB speaker apparatus according to a second embodiment of the present invention will
be described. FIG. 3 is a block diagram showing the configuration of an MFB speaker apparatus
according to a second embodiment of the present invention. In the figure, the input signal source
1, the power amplifier 2, the speaker 10, and the characteristic correction circuit 9 are the same
as those of the first embodiment, and the description thereof will be omitted. Unlike the first
embodiment, the speaker unit 5 and the passive radiator 12 attached to the cabinet 11 are
respectively provided with a first detector 13a and a second detector 13b for detecting the
vibration. The detectors 13a and 13b are the same as the detector 13 of FIG. 1, and are sensors
that detect the vibration acceleration of each diaphragm.
[0018]
The outputs of the detectors 13a and 13b are applied to a first feedback circuit 14a and a second
feedback circuit 14b. Similar to the feedback circuit 14 shown in FIG. 1, the feedback circuits 14a
and 14b respectively generate an acceleration signal of the diaphragm output from the detectors
13a and 13b, a velocity signal obtained by integrating the acceleration signal, and a position
signal obtained by further integrating the velocity signal. Is a circuit that changes the gain and
phase of these signals and outputs a feedback signal. The outputs of feedback circuits 14 a and
14 b are added together and provided to power amplifier 2.
08-05-2019
6
[0019]
As described above, in the sound pressure frequency characteristics of only the speaker unit 5 of
the speaker 10 when MFB is not applied, even if there is a sharp drop in sound pressure of the
speaker unit 5 at the same portion as the resonant frequency of the passive radiator 12 The
acceleration signals of the speaker unit 5 and the passive radiator 12 are processed and fed back
together. Then, the change in phase of the passive radiator 12 is detected by the detector 13b, so
that the rapid change in phase of the speaker unit 5 and the passive radiator 12 can be
suppressed, and the frequency characteristic at MFB can be made flat.
[0020]
In the first and second embodiments, the detectors 13, 13b and 13a respectively detect the
accelerations of the passive radiator 12 and the speaker unit 5, but these detectors may be the
velocity, the amplitude or the diaphragm of the diaphragm. These combined signals may be
detected. If the sensor is a sensor that detects the speed of the diaphragm, it is effective to
increase the damping of the speaker unit 5 equivalently, and if the sensor is a sensor that detects
the amplitude, the suspension of the speaker unit 5 It is effective when you want to stiffen
equivalently.
[0021]
As described above, according to the present invention, it is possible to expand the bass
reproduction limit frequency of the speaker device and to reduce the harmonic distortion in the
high-tone reproduction region. In particular, even if the sound pressure frequency characteristics
of the speaker unit when MFB is not applied drop sharply near the resonance frequency of the
bass reflex port or the passive radiator, if the vibration of the passive radiator is detected and a
feedback signal is given to the power amplifier, The abrupt phase change of the diaphragm of the
speaker unit can be suppressed to stabilize the MFB feedback characteristic. Furthermore, by
extracting the sound pressure from the passive radiator to the outside, the sound wave can be
emitted from a wide cross-sectional area, so that an excellent MFB speaker device with a sense of
auditory sense can be realized.
08-05-2019
7
[0022]
Brief description of the drawings
[0023]
1 is a block diagram showing the configuration of the MFB speaker apparatus in the first
embodiment of the present invention.
[0024]
2 is a graph showing the sound pressure frequency characteristics of the first embodiment of the
present invention and the conventional MFB speaker device.
[0025]
<Figure 3> It is the block diagram which shows the constitution of the MFB speaker device in
2nd execution example of this invention.
[0026]
4 is a block diagram showing an example of a conventional MFB speaker apparatus.
[0027]
FIG. 5 is a graph showing the sound pressure frequency characteristics of the speaker unit and
the bass reflex port or the passive radiator when MFB is not applied.
[0028]
Explanation of sign
[0029]
Reference Signs List 1 input signal source 2 power amplifier 5 speaker unit 9 characteristic
correction circuit 10 speaker 11 cabinet 11a baffle plate 12 passive radiators 13, 13a, 13b
detectors 14, 14a, 14b feedback circuit
08-05-2019
8
Документ
Категория
Без категории
Просмотров
0
Размер файла
17 Кб
Теги
jph05183978
1/--страниц
Пожаловаться на содержимое документа