JPS59211399A - Device for correcting group delay characteristic for speaker - Google Patents

Abstract

PURPOSE:To make the group delay characteristic constant independently of a frequency by dividing an audible frequency band signal into plural frequency band signals and adding a signal having a different delay time respectively to this signal so as to synthesize the plural signals. CONSTITUTION:The device consists of a filter 30, delay circuits 32, 34, 36 and an adder circuit 38. The filter 30 divides an audible frequency band signal Si into three frequency band signals S1, S2 and S3 of high, medium and low frequency bands. The delay circuits 32, 34, 36 provide respectively different delay times T1, T2a, T3 to the three signals S1, S2, S3 whose frequency bands are divided by the filter 30. The adder circuit 38 synthesizes three outputs S11, S12 and S13 obtained through the delay circuits 32, 34, 36. A synthesized signal S0 is inputted to a speaker system of the multi-way system via an amplifier 42 for driving speaker from an output 40.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a group delay characteristic correction device for speakers, and particularly to a device for correcting group delay phenomena occurring in multiway speaker systems.

FIGS. 1A, 1C, and 1C illustrate the concept of group delay characteristics of a multiway speaker system.

First, FIG. 1(fL) shows the relative positional relationship of each speaker with respect to the listening point 70. In the speaker system shown in the figure, three types of speakers 12 and l-6-120, each having a different frequency band for reproduction, are installed in a cabinet 10.
attached to the front baffle of the This allows the first
As shown in the figure (kl), the whole has one wide reproduction frequency characteristic (response). In the figure, the distance between the dome baffle and the listening point 70 is shown. Also, fl, f, each speaker 12.16.20
Indicates the cutoff frequency (crossover) of

Here, the distances d5, d between the baffle collars of each voice coil 14.18.22 of the three speakers 12.16.20
7 and d4 are different from each other, as shown in FIG. 1(a). Therefore, as shown in FIG. 1(C), the delay time at the listening point 70 differs for each frequency band. That is, the distance d4, d of each speaker 12.16.20 to the baffle of the voice coil 14.18.22
2, d3 and the distance d from the baffle to the listening point 70.

Accordingly, at the listening point 70, T for each divided frequency band is
. A delay time of +T1, To+'r, and To+T3 occurs. Here, T1, T2, T are distances dIsd2,
d, To is the distance d. This is the delay time caused by

As described above, in the multiway speaker system, the group delay time of the output sound pressure reaching the listening point from each speaker is different. Therefore, the position of the front baffle of the speaker cabinet 10 was changed to speaker +2.16.2 as shown in Fig. 2.
A multi-way speaker system has been proposed in which the positions of the voice coils 14, 18, and 22'j are made constant by changing the number of zeros in stages for each type. However, in this system, since the cabinet has a special shape, its structure becomes complicated, and there are disadvantages such as poor space utilization and a large installation space required. Furthermore, since the baffle is formed in a step-like shape, a diffraction phenomenon occurs in the baffle, which causes a serious drawback in that it disturbs the sound pressure characteristics or the waveform transmission characteristics and deteriorates the aurally reproduced sound quality.

This invention was made in view of the above problems.
The purpose of this is to maintain the group delay characteristics constant regardless of frequency, whether it is a speaker system using a normal cabinet or a conventional multi-way speaker system, without using a specially shaped cabinet. As a result, sound pressure characteristics or waveform transmission characteristics can be made more faithful, and high-quality playback sound can be obtained.
Another object of the present invention is to provide a group delay characteristic correction device for a speaker that can clarify sound image localization.

To achieve the above object, the present invention includes a filter that divides an audio frequency band signal into a plurality of frequency band signals;
This filter divides the frequency band and is characterized by having a delay circuit that gives different delay times to a plurality of signals, and an adder circuit that combines the plurality of outputs obtained through this delay circuit.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 3 shows an embodiment of a group delay characteristic correction circuit for speakers according to the present invention. Particularly, FIG. 4(a) shows its circuit configuration, and FIG. 2(b) and (C) show its characteristics.

First, the device shown in FIG. 8 (8) is composed of a filter 30, delay circuits 32, 34, 36, and an adder circuit 38. The filter 30 converts the audio frequency band signal S] into three frequency band signals "'IX"2 of high, middle and low frequencies.
,S,. The delay circuits 32, 34, and 36 provide different delay times T5 to the three signals S1, "'2,"'3 whose frequency bands are divided by the filter 30, respectively.
, T2, and T3 are given.

The adder circuit 38 outputs the three outputs SI+, +1! obtained through all the delay circuits 32, 34, and 36. , "+3. Then, the synthesized signal S is input from the output 40 to the multi-way speaker system via the speaker driving amplifier 42.

Here, the delay circuits 32, 34, and 36 are circuits that provide a fixed delay time for each band, and include delay lines, BB
A constant delay element such as D (charge transfer element) is used. Further, the same effect can be obtained with a circuit that generates a relative delay time difference by a combination of phase shift circuits such as a CR (capacitor and resistor) circuit and an LC (inductor and resistor) circuit. The above delay time TI, 121% T3,
In relation to the group delay times T, , T2, and T3 in the multiway beaker system of FIG. 1, T0n = T,
+T3-T.

There is a relationship between That is, the group delay time T11Tl! which occurred in the speaker system of FIG. 1! , T0n, T, such that T3 is corrected and made constant.
is set.

FIG. 3(b) shows the delay time characteristics at the output 40 of the above device. The output S has such characteristics. When given to the speaker system in Figure 1, the listening point is 70.
The arrival time of the sound pressure from each speaker 12, 16, 20 is approximately constant (T++T
s).

As a result, the sound pressure characteristics or waveform transmission characteristics are made more faithful, and the sound image localization becomes clearer.

Furthermore, by making the division frequency of the frequency division filter 30 variable, it is possible to easily accommodate speaker systems with different cut-off frequencies or with different characteristics of speakers constituting a multiway system.

Delay times T1, T, given to the signals S1, S2, S3 divided into a plurality of frequency bands by the filter 20
By making a and T variable, it becomes possible to easily accommodate differences in the structure of cabinets, speakers, etc.

Furthermore, the cutoff frequency f7, f of the filter 30.

and a delay time T5 given to the signals S1, S7, and S3 divided into a plurality of frequency bands by this filter 30,
By making both T and aXT variable, it becomes possible to easily support a multi-way speaker system of any configuration.

Note that the above-described embodiment is applied to a 3-way speaker system, and can also be configured to be applied to a 7'vJEs 2-way or 4-way or more system.

As described above, the group delay characteristic correction device for speakers according to the present invention can be applied to a group delay characteristic correction device for speakers without using a specially shaped cabinet, in a speaker system using a normal cabinet, or even in a conventional multi-way speaker system. The delay characteristics can be made constant regardless of the frequency, which makes it possible to faithfully reproduce sound pressure characteristics or waveform transmission to obtain high-quality reproduction sound, and to clarify sound image localization. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a multi-way speaker system, in which (a) is a cross-sectional structural diagram, (1))
, (C) is a diagram showing its characteristics, and Figure 2 is a multi-sea urchin r
A cross-sectional structural diagram showing another example of the system speaker system,
FIG. 3 is a diagram showing an embodiment of the group delay characteristic correction device for speakers according to the present invention, where (=) is a circuit diagram thereof;
(1)) and (C) are diagrams showing the characteristics. Identical members in each figure are given the same reference numerals, 10 is a speaker cabinet, 12.16.20 is a speaker, 14.
18.22 is the voice coil, T3, T7, T, a, T
3 is a delay time, 20 is a filter, 32, 34, 36 is a delay circuit, 38 is an adder circuit, and f8 and f2 are cutoff frequencies. Agent: Masuo Oiwa, patent attorney

Claims (1)

[Claims] +11 A filter that divides an audio frequency band signal into a plurality of frequency band signals, a delay circuit that gives different delay times to each of the plurality of signals whose frequency bands are divided by the filter, and a 1. A group delay characteristic correction device for a speaker, comprising an adder circuit for synthesizing a plurality of obtained outputs. (2) A group delay characteristic correcting device for a speaker, characterized in that the cut-off frequency of the frequency division filter is made variable in the device according to claim fl. (3) A group delay characteristic correction device for speakers according to claim (1) or (2), characterized in that the delay time given to the signal divided into a plurality of frequency bands by the filter is variable. . (4) In the device according to any one of claims il+, (2), and (3), both the cutoff frequency of the filter and the delay time given to the signal divided into a plurality of frequency bands by the filter are variable. A group delay characteristic correction device for speakers, characterized in that: