JPH02265400A - Loudspeaker - Google Patents

Abstract

PURPOSE:To vary the directivity in response to the purpose and applications by dividing lots of vibrators arranged on a same plane into plural sets in a ring and adjusting properly a phase delay angle of a modulation signal resulting from modulating a carrier high frequency signal with a sound signal applied to each vibrator. CONSTITUTION:Lots of vibrators 11, 12, 13, 14 arranged on a same plane (mounting plate 11) are divided into plural sets in a ring and a modulation signal fm resulting from a carrier high frequency signal fo with a sound signal fs is applied to the vibrators 11, 12, 13, 14 via phase delay devices 51, 52, 53, 54 respectively and phase delay angles theta1, theta2, theta3, theta4 of the said phase delay devices 51, 52, 53, 54 are adjusted properly to adjust the directivity by using a directivity adjustment means. Two ultrasonic waves (f1, f2) generated respectively corresponding to upper and lower side bands radiate in air and the sound of the audible tone of the difference frequency (f1-f2), that is, the original sound signal fs is reproduced by nonlinear interaction of both the ultrasonic waves in air.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a loudspeaker whose directivity can be changed.

[Prior Art] Figures 7 and 8 show a portable loudspeaker (portable megaphone) using a trumpet speaker.
2, an amplifier 13 that amplifies the audio signal output from the microphone 12, and a trumpet speaker 15 with a horn 15a driven by the signal amplified by the amplifier 13.
The amplifier 13 is connected to the amplifier 13 via a push-on power switch 16.
The trumpet speaker 15 amplifies the sound collected by the microphone 12 and generates a loud sound from the trumpet speaker 15. The sound volume can be adjusted with a volume control volume 14. Reference numeral 14 in the figure is a volume control volume.

[Problems to be Solved by the Invention] However, in the above conventional example, in order to prevent howling and to make the sound reach a long distance, the trumpet speaker 15 with the horn 15a is used to provide appropriate directivity. However, since a large horn 15a is required, there is a problem that the shape becomes large.

In addition, the directivity of the horn 15a is adapted to convey information to a relatively wide area nearby, and since the directivity is fixed, it is necessary to convey information to people in a specific narrow area far away. There was a problem in that case.

On the other hand, if a parametric speaker with sharp directivity is used as a loudspeaker, it is possible to convey information only to people in a specific narrow area far away, but on the other hand, when you want to convey information to people in a relatively wide area nearby. There was a problem that it was not possible to respond to

The present invention has been made in view of the above points, and its purpose is to be able to transmit information by changing the directivity depending on the purpose and use, to be versatile, and to be compact. Our goal is to provide loudspeakers.

[Means for Solving the Problems] The loudspeaker of the present invention divides a large number of vibrators disposed on the same plane into a plurality of sets in an annular shape, and modulates a carrier high frequency with an audio signal, and then modulates each modulated signal with a phase delay. Directivity adjusting means is provided for adjusting the directivity by applying an electric current to each set of vibrators through a device and suitably adjusting the phase delay angle of the phase delay device.

[Function] The present invention is constructed as described above, in which a large number of transducers arranged on the same plane are divided into a plurality of groups in an annular shape, and the carrier high frequency applied to each group of transducers is converted into an audio signal. This device is equipped with a directivity adjustment means that adjusts the directivity by appropriately adjusting the phase delay angle of the modulated signal, and can transmit information by changing the directivity depending on the purpose and application. This makes it possible to provide a highly versatile and compact loudspeaker.

[Embodiment] FIGS. 1 to 4 show an embodiment of the present invention, in which a large number of vibrators 1. ．． 1
□, is, and 14 are divided into a plurality of groups (four groups in the embodiment) in a circular manner, and the modulated signal fm obtained by modulating the carrier high frequency f0 with the audio signal fs is transmitted to each group through phase delayers 51, 52, 53, and 54, respectively. The voltage is applied to the set of oscillators 11+ 1t+ 13114, and the phase delay device 5. .

52.53.54 phase delay angle θ1. θ2. θ1. θ.

A directivity adjustment means is provided for adjusting the directivity by appropriately adjusting the directionality. In the embodiment, the directivity adjustment means includes a directivity adjustment volume 6 and a delay angle setting circuit 71 .
72, 73, and 74. Also, oscillator 2
The carrier high frequency f0 generated at is input to the modulator 3,
The audio signal fs output from the microphone 12 is modulated by a signal amplified by an amplifier 4. Furthermore, the drive signals appropriately delayed by the phase delayers 51152, 53, and 54 are transmitted to amplifiers 88, 8□, and 83, respectively.
It is amplified at ゜84 and vibrator 11.12.1-. 1-, and the amplification degree of the amplifier 81182.8*, 84 is set by the volume control volume 9 and the amplification degree setting circuit 1010□,
10s, 104. In the embodiment, four sets of vibrators 11+12.1, 1° are used, but n sets of vibrators 15,1□ arranged in a ring are used.
...1n may be used.

The operation of the embodiment will be described below. Figure 5 shows the operating principle of a parametric speaker that uses the nonlinear interaction (nonlinear parametric action) of sound waves in the air.
, is radiated into the air as shown in Figure 5(a), and this 2
By interfering two sound waves fl+f2 in the air (using the nonlinearity of air), the sound waves f + + f2, ft f2, which have a sum frequency and a difference frequency, are generated as shown in Fig. 5(b).
Here, two sound waves fl+
By setting fz to be an ultrasonic wave and making the difference frequencies f and -f audible, the audible sound generated in the air can be sent to a specific area with sharp directivity.

By the way, in the embodiment, the vibrator 1 is activated by a modulated wave fm obtained by amplitude-modulating a carrier high frequency f with an audio signal (audible sound signal) fs.
3.1□, 1i+14 is driven, and this modulated wave f
As shown in FIG. 5(c), m has an upper side band wave and a lower side band wave, and two ultrasonic waves (f I + f t) generated corresponding to the upper and lower side band waves are The sound wave is radiated into the air, and the audible sound at the difference frequency (ft-rz), that is, the sound corresponding to the original sound signal fs, is reproduced by the nonlinear interaction of the image sound wave in the air.

Here, in the embodiment, by adjusting the directivity adjustment volume 6 provided on the back of the loudspeaker You can set it narrowly (sharp directivity) to transmit information to a specific area far away, or you can set the area where audible sound is played relatively wide and set the directivity to be relatively wide, as shown in Figure 6(b). wide) can be set to transmit information to a large nearby area. Therefore, the directivity can be changed depending on the purpose and use, and a versatile loudspeaker X can be provided. Furthermore, since sharp directivity is achieved without using the large horn 15a as in the conventional example, a compact loudspeaker X can be realized.

[Effects of the Invention] The present invention is configured as described above, in which a large number of transducers disposed on the same plane are divided into a plurality of sets in an annular shape, and the carrier high frequency applied to each set of transducers is converted into an audio signal. It is equipped with a directivity adjustment means that adjusts the directivity by appropriately adjusting the phase delay angle of the modulated signal, and can transmit information by changing the directivity depending on the purpose and use. This has the effect of providing a versatile and compact loudspeaker.

[Brief explanation of drawings]

FIG. 1 is a front view of the main parts of an embodiment of the present invention, FIG. 2 is a side view of the main parts of the same, FIG. 3 is a block circuit diagram of the same, and FIG.
&) is a cross-sectional view of the same as above, FIG. 4(b) is a front view of the same as above, FIG. 4(e) is a rear view of same as above, FIGS. &) is a cross-sectional view of the conventional example, FIG. 7<b> is a front view of the same as above, and FIG.
FIG. 8 is a block circuit diagram same as the above. 1+, lx, Is, 14 is a vibrator, 2 is an oscillator, 3 is a modulator, 4 is an amplifier, 51.51515- is a phase delayer,
6 is a directivity adjustment volume. Agent Patent Attorney Ishi 1) Chief 7 Figure 4 (a) (b) Figure 1 Figure 2 (C) Figure 5 (a) (b) (C)

Claims (1)

[Claims] (1) A large number of vibrators arranged on the same plane are divided into a plurality of groups in an annular shape, and a modulation signal obtained by modulating a carrier high frequency with an audio signal is applied to each group of vibrators via a phase delay device,
A loudspeaker comprising a directivity adjustment means for adjusting directivity by appropriately adjusting the phase delay angle of the phase delay device.