JPH02266700A - Speaker device - Google Patents

Abstract

PURPOSE:To eliminate the effect of a reflecting tone with simple constitution by in stalling two speakers subjected to band split onto a perpendicular line so as to cause a wide trough on the synthesis sound pressure frequency characteristic with the reflecting sound only thereby making the frequency characteristic of the direct sound flat. CONSTITUTION:A 2nd speaker SP2 with a high sound frequency apart by a half the wavelength of a crossover frequency is arranged to a 1st speaker SP1 with a low sound frequency arranged close to a reflection face Re in an orthogonal direction. Then the frequency characteristic of the synthesized sound pressure from virtual sound sources SP1', SP2' being the reflecting sources of both the speakers SP1, SP2 causes a wide trough at the crossover frequency and the frequency characteristic of the synthesized sound pressure of direct sounds is made flat by using a band split filter. Thus, the change in the overall sound pressure frequency characteristic is decreased independently of the presence or absence of the reflection with simple constitution to obtain excellent reproduced sound.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is installed in a place that has a reflective surface such as a wall surface that reflects sound from a speaker either on the side or above and below, and the sound from the speaker is reflected from the reflective surface. The present invention relates to a speaker device that improves disturbances in sound pressure frequency characteristics caused by interference of sound waves due to reflections of sound waves.

[Conventional technology]

There are the following three types of conventional speaker apparatus principles or configurations for improving the disturbance in sound pressure frequency characteristics caused by the reflection of sound waves from reflective surfaces of this type.

The first is a speaker system described in Japanese Patent Publication No. 60-31396, in which a normal speaker device itself is used, and the input electrical signal is processed in advance to equivalently cancel reflected sound. It is.

The second problem is when driving multiple speakers at the same time, such as the speaker system described in Japanese Patent Publication No. 5B-22912 and the speaker device described in Utility Model Application Publication No. 56-63180, their directional characteristics or By making the phase characteristics different, the reflected sound itself is prevented, or by combining the direct sound and the reflected sound, the reflected sound is canceled out.

The third method is to use a plurality of speakers with divided bands, such as the speaker device described in Japanese Patent Publication No. 60-1998 and the speaker system described in Japanese Patent Application Laid-Open No. 6(2008)-208198, and use reflected sound to create a valley. This system compensates for the frequency characteristics by adding a speaker that shares the frequency band that produces this.

[Problem to be solved by the invention]

The above-mentioned first speaker device processes the input electric signal, so an expensive and complicated processing device is required. This requires changing the device and processing conditions, making it difficult for the user to adjust the processing device according to the conditions at the location where the speaker device is installed.

In addition, in the second speaker device, at least one speaker must have extremely unique directional characteristics that do not radiate sound in the direction of the reflecting surface, and the listening position must be far away from the speaker and in the direction of the reflected sound. This is difficult to achieve when the angle formed between the direct sound direction and the directivity angle is small.

Furthermore, in the third speaker device, a dedicated speaker is added that is unnecessary when reflected sound, which is the case when used on a boat, is not taken into account, and a band division filter is also required for this purpose.

In addition, in order to compensate for the synthesis characteristics of direct sound and reflected sound, it is difficult to respond to changes in the conditions of the reflecting surface and the listening position, as in the first speaker device.

[Purpose of the invention]

The present invention solves the problems of each of the above-mentioned speaker devices that take reflected sound into consideration, does not require processing input electrical signals, does not require the addition of a special speaker or its band division filter,
Moreover, it is an object of the present invention to provide a speaker device with a simple configuration that can cope with changes in the conditions of the reflecting surface and the listening position.

[Summary of the invention]

The present invention relates to means for a speaker device for achieving the above-mentioned object, and in which a first speaker in a bass range is arranged close to a reflecting surface and perpendicular to it, and is separated by two or more wavelengths of a crossover frequency. A second high-frequency speaker is placed in the center, and the frequency characteristics of the synthesized sound pressure from the virtual sound source reflected by both speakers produce a wide valley at the crossover frequency, while the frequency characteristics of the synthesized sound pressure of the direct sound are flat. A band division filter is provided.

[Embodiments of the invention]

Next, in order to make it easier to understand the principle of the present invention, an example will be described with reference to FIG. 1 in which the only reflective surface is the floor surface and two speakers are used.

Now, from the listening position MIC to the second high frequency speaker SP
Assume that the distance D2 to t is sufficiently long, and that a phase difference occurs due to a distance difference from another low-frequency first speaker SP, but a distance attenuation difference does not occur.

Furthermore, for the sake of simplicity, the reflectance of the reflective surface Re is assumed to be 1°0 (total reflection), and each of the speakers SPI and SPz is assumed to be non-directional.

If the sound source of the virtual speaker generated by the reflective surface of the first speaker SP for low frequency is SP,', and that of the second speaker SPz for high frequency is SP2', then the listening position fMic is
The synthesized sound pressure Pt from the four sound sources in is expressed as a superposition of four sine waves having different phases.

That is, if the sound pressure from the second speaker SP z is taken as the reference 1, then the synthesized sound pressure Pt is: wave number (=2πf/c) f: frequency C: sound speed d+: D+ Di d+: R, D2 dz: Rz 02 Furthermore, it is understood that the synthesized sound pressure Pd of only the direct sound and the synthesized sound pressure Pr of only the reflected sound can be set as follows: Pd=2 and Pr=O.

However, each of the above equations indicates that the phase changes depending on the frequency, and it is impossible to satisfy the above conditions over a wide range of frequencies.

On the other hand, the configuration of a normal speaker device and the listening position MI
C is HI=500 cylinder in Fig. 1, H2=700mm, D
= about 2m.

In this case, d+'; 10mm, d+"; 330mm, d
z': 440 mm.

However, at a frequency where each of the above distances is 2 of the wavelength λ, the sound pressure from the first speaker SP + and the sound pressure from the other speakers SPz and SPI 'tspz' are 1.
They become a phase difference of 80 degrees, cancel each other out, and form a valley in the sound pressure frequency characteristic.

In the above case, d can be ignored, but since d, / and d2' are relatively close, their average frequency fd = 380
A relatively wide valley is generated around the frequency 440H2 where mm=λ/2.

In addition, in the case of a normal speaker device, the first speaker SP
+ and the crossover frequency f of the second speaker SP2
c is often set to 440H2 or more of the average frequency fd.

Therefore, in the present invention, the crossover frequency fc is set near the average frequency fd, the first speaker SP is placed closest to the reflecting surface, and the above-mentioned dlyd1' and d
By setting 2' and crossover conditions as shown below, the conditions of Pd=2 and Pr=O described above are approximated.

That is, the phase difference (lead) of the first speaker SP with respect to the second speaker SP at the crossover frequency fc
If ψ is 0〈Δψ−kd, <30°45°〈Δψ−kd, '<30°−210°〈Δψ−kd+kdz'＜150
It is sufficient to set the following conditions.

For example, H1=150mm, H,=700 plates, D==2
200+nm, fc=300Hz, first speaker SP
, with a 4.4 dB attenuation at the crossover frequency fc12
Pass through a dB10ct low-pass filter LPF, and pass a 6dB10at bypass filter HPF that attenuates by 3 dBN at the crossover frequency to the second speaker SP2.
Both filters LPF and HPF at crossover frequency fc
are connected so that the absolute values of the output levels are the same and the phases are different by 180°.

Then, ψ, = -67,5° (ψ,: Phase of first speaker SP at fc) ψz = +45° - 180° = -135° (ψ2: fc
phase of the second speaker SP2) ψ2−ψ, = −67,5°, °, Δψ=67.5“
That is, the first speaker SP has a phase lead of 67.5° with respect to the second speaker SP.

Also, d+=140mm, °, kd,=45°t
L'=260mm,',kcL=
84°d, =550mm,',kd2
= 177°λ c = 970peng, so if the direct sound from the second speaker SP is taken as reference 1, then +1 + j (sin (22,5°)) = 1.
'92+j 0.38,', Pd = 1.96 = cos (-16,5°) + cos (-17
7° )++ j (sin(-16,5°)
+5in(-177°)=-0,04-j O
,34 ,', Pr =0.34 Therefore, the absolute value R of the ratio of reflected sound PrO to direct sound Pd
Also, the synthesized sound pt of the direct sound Pd and the reflected sound Pr is Pt=P,
+Pr-(1,92+30.38)+(-0,04
-jo, 34) = 1.88 +30.04 1Pt = 1.88 Thus, at the crossover frequency fc, there is almost no change in the level of the direct sound and the level of the synthesized sound, and the influence of the reflected sound It can be seen that has been removed.

A simulation of the sound pressure frequency characteristics of the conventional example as described above is shown in FIG. 3, and that of the above-mentioned embodiment of the present invention is shown in FIG.
The actual measurements are shown in Figure 5.

In the above embodiment, two speakers were housed in one cabinet, but a port other than the speaker can be used as a sound source, and the cabinet also has separate ports for low and high frequencies. You may also use

In the figure, A is the total synthesized sound pressure, B is the direct synthesized sound pressure,
C indicates the reflected sound synthesized sound pressure.

In this case, it is also possible to use a speaker housed in a small cabinet as a sound source for high frequencies and place it on a large cabinet for low frequencies to form a speaker device in the form of a stand.

〔Effect of the invention〕

In the present invention, by rearranging the two band-divided speakers on a line perpendicular to the reflecting surface and setting the crossover condition to a constant condition, the synthesized sound pressure of only the reflected sound is achieved. A wide valley is created on the frequency characteristics, and the frequency characteristics of the direct sound are made flat.

Therefore, there is little change in the overall sound pressure frequency characteristics between the presence and absence of reflection, and it is possible to obtain high-quality reproduced sound.

In addition, unlike conventional speaker devices that take this type of reflective surface into consideration, there is no need to add a special speaker or use an electrical processing device to process the input signal of the speaker, making it easy and environmentally friendly. It is possible to provide an economical speaker device that can respond to changes in the conditions of the reflecting surface.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram thereof, Fig. 3 is a simulation diagram of sound pressure frequency characteristics of a conventional speaker device, and Fig. 4 is an embodiment of Fig. 1. Figure 5 is a simulation diagram of sound pressure frequency characteristics, and Figure 5 is an actual measurement diagram. S P +...first speaker, SPt...second speaker, MIC...listening position, Pd...synthesized sound pressure of direct sound only, Pr...synthesized sound pressure of reflected sound only , Pt
...Fully synthesized sound pressure. Figure 1

Claims (1)

[Claims] A first speaker for bass range reproduction is arranged perpendicularly to a reflective surface that reflects sound from the speaker and is located close to the reflective surface, and the reproduction band is crossed over to the first speaker. and a second speaker for high frequency reproduction that is separated from the first speaker by at least 1/2 wavelength of the crossover frequency, and synthesis from only the virtual sound source of both speakers generated by the reflection of sound from the reflecting surface. Input a crossover frequency, cut-off characteristic, and phase to each speaker such that the frequency characteristic of sound pressure produces a wide valley near the crossover frequency, and the frequency characteristic of the synthesized sound pressure from only both speakers is flat. A speaker device comprising a band division filter.