JPS6041395A - Method of controlling operation of speaker and speaker system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker system, and more specifically, to a speaker system that has low distortion, high output performance, and is supplied with power over a wide band and width. .

Speakers installed in free air conditions and in infinite baffle arrangements, such as those used in automobiles, usually suffer from intermodulation distortion, low sound pressure output, and low efficiency.

at a certain output level (e.g. 10
0(it)), if the loudspeaker driver is optimized for an increased sound pressure level (e.g. 106d
It is known that when a speaker is driven by an input signal corresponding to the minimum dynamic headroom required for reproducing sound with high fidelity, distortion increases. In extreme cases, the erratic movement of the speaker cone may cause the speaker's voice coil to pop out of its gap.
Intermodulation distortion of up to 30% will occur. conventionally,
This problem has been avoided by using stiffer support spiders and converter edges to control the movement of the speaker diaphragm. However, this results in a sharp drop in speaker efficiency and increases the drop in efficiency at low output levels.

For intermediate power amplifiers that are configured to drive a loudspeaker to produce a low sound pressure level, it is almost impossible to optimize the loudspeaker sensitivity (which is a function of support and magnetic flux). It is possible. In this case, the sound pressure level is not linear with increasing power (ie, it increases by 3ab when the power input is doubled).

The specifications and data cited by manufacturers for standard speakers are insufficient to determine whether a speaker is of good quality or bad. At varying power and frequency levels, their specifications usually state that the speaker does not operate at a constant efficiency, but rather operates with constantly varying efficiency. Speakers with the same frequency response characteristics may have different efficiency characteristics.

Furthermore, multi-speaker devices to which multiple signal inputs are applied tend to cause cross-modulation distortion and non-linearity problems.

Conventional speaker systems generally do not solve the problem of efficiency nonlinearity at different output levels. This problem is easily detected when the loudspeaker is operated at various sound pressure levels, indicating that the information reproduced by the loudspeaker is not constant in terms of the frequency content it contains. The fact that at low output levels, the human ear is less sensitive to very low (and high) frequency sounds at low levels, e.g. 5Qdb, than at high levels, e.g. 100 (11). Requires a large low Zhou faction level increase. At high sound pressure levels, the ear/brain strings perceive all frequencies with approximately equal loudness.

If we consider a loudspeaker as a radiator of sound waves, the purpose of which is to transmit the entire sound spectrum to the listener with precise frequency balance, it becomes clear that a linear driver (amplifier) will not achieve that performance. In other words, the driver must be modified and configured to compensate for the reduced performance of the speaker and the changing frequency sensitivity of the ear as a function of size.

Modifying the iso-wavenumber response to compensate for the non-linear dynamic limitations of a loudspeaker is achieved by using a conventional equalizer that raises the level of some frequencies by the same amount, independent of the sound output level setting. Usually done. Therefore, 6
What requires a 1Qdb level increase in odb, the equalizer also increases the level by 100db.

Also, the amplifier can output a power level corresponding to 1ioab, but since the speaker exceeds its linear limit, the speaker can only output a sound pressure level of 1o3db, but half of the sound output is distorted. . lastly,
When the voice coil A/car jumps out of the gap, an avalanche phenomenon occurs in which the magnetic flux of the coil increases in the middle current. As the current increases, the force that forces the coil out of the gap increases, resulting in a very distorted, low-pitched sound from the non-speaker.

The basic approach of the invention is that optimum performance of the speaker/stem is achieved by constructing the amplifier and speaker as an integral unit. The amplifier uses pre-emphasis applied to the input signal to change the frequency response of the drive signal applied to the speaker to compensate for the output limitations of the speaker and the fact that the sensitivity of the human ear varies with the same wave number. including a device for dynamically changing the amount of By combining it with a speaker that is an electronic amplification circuit, its characteristics can be improved, making it possible to increase sound pressure, expand the frequency response curve, and reduce distortion. The degree of pre-emphasis, and therefore the frequency response of the signal to power, can be varied dynamically as a function of the level of the input signal and can be configured to take into account the speaker amplifier system.

The object of the present invention is to control the movement of a loudspeaker coil in a magnetic field under optimal conditions and at various sound pressure levels.
1lJ
[t-control] is to obtain a dynamic electronic circuit controlled by an input signal.

Another object of the invention is to obtain an acoustic radiator which increases the maximum sound output, extends the frequency response curve and substantially eliminates distortion by predetermining the maximum movement of the loudspeaker diaphragm. . Yet another object of the invention is to provide an improved acoustic radiator unit that is simple in construction and inexpensive.

The present invention provides a self-powered speaker system that dynamically modifies the audio signal with an electronic control circuit before it is applied to the speaker coil driving power amplifier.
The purpose is a method for controlling the performance of speakers in a system.

Hereinafter, the present invention will be described in detail with reference to the drawings.0 With reference to FIG. attached to the back. (If desired, the control circuitry can be physically separated from the power amplifier and speaker.) The drive includes a heat sink 14. Since this radiator is located between the cone diaphragm 16 and the drive, the advantage is that the air drum generated by the movement of the diaphragm helps cool the drive. Connection 18 between the drive and the two loudspeakers for high and low frequency ranges
is provided.

Refer now to FIG. The drive device 10 includes a preamplifier 20
including. This preamplifier receives an input signal and provides the input signal to a constant speed control circuit, cva21-\. This aVC includes a branching unit 22. This splitter separates the input signal into a high frequency range and a low frequency range. The high frequency signal from the splitter is applied to a first DC converter/time constant network 24, which provides low Ii! The tI wave signal is provided to a second DC converter/time constant network 26. The two networks produce a DC output signal that is a function of the magnitude of the input signal. Those DC converters/time constant circuit networks 2
The DC output signal of 4.26 is used to control the high frequency active voltage regulator shaping circuit 28 and the low frequency active voltage I11 regulator shaping circuit 30, respectively. The outputs of these active suppression #shaping circuits 28, 30 are provided to a constant velocity equalizer 32. This equalizer receives the recombined audio input signal from frequency divider 22 and changes its frequency response as a function of the output of active voltage controlled shaping circuit 28.30. The output of the equalizer drives a power amplifier 36, which drives the speaker 12. A power supply 37 provides supply voltage to the preamplifier 20, CVA 21, and power amplifier 36. Therefore, the frequency response of the isograph 320 is the same as the high frequency active voltage control @shaping circuit 28 and the low frequency active voltage control. circuit 30
is controlled by the output of These active voltage control 11 shaping circuits are controlled by a DC voltage proportional to the magnitude of the audio input signal. For low level input signals,
The active voltage control shaping circuit increases the level of the lowest and highest frequencies on the isolator, firing maximum effect. When the level of the input signal is high (the level rise decreases and eventually the low frequency cutoff is moved upwards), the cutoff frequency moves upwards because the speaker cone moves the most at low frequencies. The total output level of the loudspeaker can be increased without exceeding the maximum travel limit of its cone.Thus, the device dynamically equalizes the loudspeaker as a function of the magnitude of the input signal. The purpose of the transformer is to control the movement of the speaker diaphragm regardless of the mechanical flexibility of the speaker diaphragm, and to prevent the speaker voice coil from moving out of the optimal magnetic flux region. This greatly improves efficiency and allows the speaker to reproduce distortion-free waveforms at high sound pressure levels.

%t1111141 circuit 10 and speaker system 12
is an integrated device, and the details of the magnitude of the input signal and its varying power and speed are determined by the mechanical and structural limits of the loudspeaker and the movement of the coil in the magnetic field. - determined according to the limits of mechanical properties of -.

The high frequency operation controlled by converter 24 and active voltage leg shaping circuit 28 is performed to maintain balance in the overall sound reproduction of the speaker system, rather than by taking into account the movement of the speaker cone. It will be destroyed.

Low frequency response is achieved by converter 26 and active voltage control shaping circuit 3.
0 in conjunction with the equalizer 26, there may be an imbalance between high and low frequencies in the reproduced signal.

Since the low frequency response is controlled, the rise characteristics of the high frequency spectrum should also be controlled.

The converter 24 is configured such that the device enters dynamic control of the high frequency range when the high frequency portion of the input signal reaches a level corresponding to a sound pressure level higher than about 8 db at 4KH2.
The high frequency active voltage control shaping circuit 28 operates. This prevents high frequencies from masking low frequencies at high output levels. The purpose of the high@wave control part of this device is not to control the movement of the speaker coil (
The aim is to optimize the balance between the high and low frequency ranges (because in the high frequency range too much movement of the diaphragm is not important).

Reference is now made to FIG. 3 in which a more detailed circuit diagram of the present invention is shown. Pad 38 containing resistors R1, R21R3
An input signal is given to. The signal from this pad is applied to a preamplifier 20, which includes a resistor 01 and a resistor "4r R5. The output of this preamplifier is fed to a high frequency network 22.
a and a low-frequency circuit network 221). The high frequency circuit network consists of capacitors c1, R2 and resistor aR.
Includes 9°R10 and engineering C3. The low-pass network includes capacitor C3, resistor R6PR7#R8, and resistor C2.

(The output terminals of 32 and xa3 are mixed resistors R29 and R3.
0 respectively. The common connection of these resistors is connected to the input terminal of the constant speed equalizer 04. Labor 0
2. The output terminal of the circuit 3 is also coupled to the DC converter/time constant network 24,26.

The network 24 includes an isolation resistor R11 and a full wave rectifier. The full wave rectifier includes diodes D1 and D2. The negative DC' voltage from diode D2 is connected to an RC circuit consisting of resistor R13, charging capacitor C4, and discharging resistor R15.
High frequency active voltage control I11 shaping circuit 2 through the circuit network
80 input terminal. The voltage across the terminals of the capacitor C4 is a DC voltage proportional to the magnitude of the high frequency portion of the input signal, and is used to control the high frequency active voltage control shaping circuit 28.

The DC converter 26 includes resistors R12, R14, R16 and a diode D3. D 4 and capacitor C5, operating similarly to capacitor 24. The operating speed of this device is determined by resistor R15 and capacitor C4 of converter 24, and resistor R16 and capacitor C5 of converter 2G. .

The output of the converter 24 is connected to the high frequency active voltage control shaping circuit 2.
8, especially the FK of the high frequency active voltage control shaping circuit 28
The high frequency active voltage controlled shaping circuit 28, which is the control input to the TI, operates as an active conductor. This active conductor resonates as a function of the value of the input signal to FET1.

The high frequency active voltage control shaping circuit 28 is connected to resistors R17 to R2.
0, capacitor c6, R7, and transistor TR1
including. FETI operates as a voltage controlled resistor, the resistance of which varies depending on the value of the DC output signal of converter 24. High wave active cage oppression till
The shaping circuit 28 applies the DC output signal to the inverting input terminal of xc4 of the constant speed equalizer 32 via the resistor R20.

Transistor TR1 operates as a resonator. The resonance point of the resonator changes as a function of the drive signal applied to the FETI.

Low local wave active voltage control@l The shaping circuit 30 uses high frequency active voltage f
It operates similarly to the tjlJ H shaping circuit 28, with 1jT2 varying its resistance as a function of the input No. 16 from the DC converter 26. This low frequency active voltage regulating #shaping circuit 30 includes resistors R21 to R24 and a capacitor 08109.
and a transistor TR2. This transistor T
The resonance point of R2 changes as a function of the drive signal applied to FFI:T2.

FF1Tl and FI! When the input voltage to i, T2 is low, i.e. when the amplitude of the input signal is low, the resonator is connected to the constant velocity equalizer 32 (comprised by 104 and feedback resistor R25) at maximum The reason is that the resistance value of the PET is low and the resonator is connected to the feedback resistor R.
This is because it can exert an effect on 25. When the input voltage to the active voltage control shaping circuit 28.30 is high (F
The resistance value of FET2 becomes high, and therefore the effect of the resonator on the constant velocity equalizer 32 becomes weak. Therefore, the frequency response of the output signal of the constant velocity equalizer 32 is dynamically varied and becomes dependent on the level of the input signal.

Once done, constant velocity equalizer 32 produces an output signal that varies in frequency response as a function of the magnitude of the input signal.

A portion of the input signal is provided directly to IO4, and the remaining input signal is used to generate a control signal to vary the response of the rc4 and resistor R25 combination. IO
The output terminal of 4 is coupled to output pad 40. Its output pad includes resistors R26 and R27. The output signal is provided to a power amplifier.

The operation of an active voltage-controlled shaping circuit is such that at low volumes, the resonator increases the level of the still and low frequencies in the output of the velocity equalizer. To limit motion, the level enhancement of high wavenumbers and low frequencies in the output of the constant velocity equalizer is reduced as the input signal becomes larger.

Next, reference is made to FIG. In the present invention, a pair of eves can be used in a double amplification configuration. In such a configuration, the input signal is provided to a preamplifier 42.\ and the output of the preamplifier is provided to an electronic crossover 44. This electronic crossover divides the signal applied to it into a high frequency part and a low frequency part. Their signal parts are given to the first cya46 and the second CVC487, respectively ◇The CVCs are cya2 shown in Figure 3.
1 (i.e., a pair of DC converters and
Each 0Vq46.48 includes a high frequency active voltage control @l shaping circuit, a low frequency active voltage control shaping circuit, and a constant speed equalizer]. The output of cya 46 is provided to power amplifier 50. This power amplifier drives a high frequency speaker 52.

The output of ava4B is given to power amplifier 54. This power amplifier drives a low frequency speaker 56. C'JC
The components composing the speakers 46 and 48 are selected to suit the characteristics of the speakers 52 and 56, respectively. Therefore, C! V
The low frequency active 'torque suppression' shaping circuit of O46 is connected to the speaker 52.
Cv
The C48's low frequency power@voltage controlled shaping circuit operates to ensure that the maximum travel limit of the speaker 52 cone is not exceeded. In this way, the multi-speaker system can be controlled to compensate for the characteristics of the valley speakers in the multi-speaker system.

[Brief explanation of the drawing]

FIG. 1 is a vertical half-sectional view of the acoustic radiation of the integrated amplifier and speaker unit, FIG. 2 is a block diagram of the speaker/amplifier device of the present invention, and FIG. 3 is the speaker/amplifier device shown in FIG. A circuit diagram showing an example of a circuit configuration of an amplifier device,
FIG. 4 is a block diagram showing an embodiment of the dual amplification configuration of the present invention. 10...Electronic drive device, 20.42-...-11 position amplifier, 21.46.48-...Constant speed control circuit, (c
ya), 22... Frequency divider, 24.26... DC converter/time constant circuit network, 28... High frequency active voltage control shaping circuit, 30... Low frequency active voltage control shaping circuit, 3
2... Constant speed equalizer, 36.54... Power amplifier,
44...Electronic crossover. Applicant's agent Takahisa Kimura Procedure:? 10 Masatomo (Method) 1981/81] 30th, 1988 Mochiju F Application No. 68921 2, Title of Invention Method and Speaker System for Controlling the Operation of Speakers 3, Matters for Making Amendments A'1 Relationship Special Br (Applicants 1 to Meeka, Friedman 4, Agents (〒104) 2TI, Ginza, Chuo-ku, Tokyo:, 111ffi
No. 2 July 11, 1980 (Shipping port: July 31, 1982)

Claims (7)

[Claims] (1) generating a control signal as a function of the magnitude of the audio input signal; applying the control signal to the isolator network to change the frequency response of the isolator network; The process of dynamically correcting the frequency response of an audio input signal as a function of its magnitude by passing it through an equalizer network and providing a corrected signal to a power amplifier that drives a loudspeaker system. 1. A method of controlling speaker operation in a self-powered speaker system comprising: (2) A speaker, a power amplifier for driving the speaker, and a control for supplying an audio drive signal to the power amplifier.
a control circuit that receives an audio input signal and includes an element that dynamically modifies the frequency response of the audio input signal as a function of its magnitude, and the modified input signal is connected to a power amplifier. A speaker system characterized in that it is a driving signal to. (3) A powered speaker system according to claim 2, comprising a converter circuitry for generating a DC control signal as a function of the magnitude of an audio input signal, and having a frequency response that is DC. an equalization circuit controlled by a control signal, and an audio input signal is passed through the equalization circuit before being applied to a power amplifier. (4) A powered speaker system according to claim 3, wherein the control circuit includes a splitter for dividing the audio input signal into a high frequency range and a low frequency range; The network includes separate controllers for generating first and second DC control signals applied to the equalization network to separately control the high and low frequency responses of the equalization network. A speaker system characterized by including a (5) a first speaker, a first power amplifier for driving the first speaker, a second speaker, and a second power amplifier for driving the second speaker; a control circuit for receiving an audio input signal that is divided into a high frequency range and a low frequency range, the control circuit dynamically correcting the high frequency range of the audio input signal; a first equalization network that dynamically corrects the low frequency range of the audio input signal and provides it to a second power amplifier; What is claimed is: 1. A dual-amplified, self-powered speaker system comprising: (6) The speaker system according to claim 5, wherein the first equalization circuitry has a frequency response of a relatively high frequency portion and a relatively low frequency portion of a high frequency range of the audio input signal. The g20 equalization circuitry includes elements for separately modifying the frequency response of relatively high frequency portions and relatively low frequency portions of the lower frequency range of the audio input signal. A speaker system comprising: (7) The speaker system according to claim 6, wherein each of the first and second equalization circuit networks divides the range of the audio input signal applied thereto into a high frequency portion and a low frequency portion. a splitter for dividing, first and second DC converters for generating first and second control signals as a function of the respective magnitudes of the high frequency part and the low frequency part, and the response of the equalization network. a first iso-wavenumber shaper for modifying the response of the equalization network as a function of the first DC control signal; and an h-wavenumber shaper for modifying the response of the equalization network as a function of the second DC 1filJ ial signal. A speaker system featuring: