JPS6326198A - Stereo reproducing equipment - Google Patents

Abstract

PURPOSE:To obtain an excellent location sense on a wide listening position in a nearby sound field by preparing three speakers facing the front, inner side and outer side with respect to one channel, constituting similarly with respect to other channels and adjusting the amplitude and phase of a signal fed to respective speakers. CONSTITUTION:When a right channel signal is noticed, since a level difference due to distance attenuation depending on the difference in path length between a speaker 9 and a listening position 21 and between a speaker 17 and a listening position 21 exists, an amplifier 6 is adjusted to correct the level difference thereby radiating a sound wave toward the listening position 21. Furthermore, with respect to a speaker 7, it is directed slightly outward to the listening position 19 and the amplifier 4 is adjusted to cause the presence in the listening position 19. Since the distance attenuation and time difference exist depending on the difference in the path length between the speaker 8 and the listening position 19 and between the speaker 16 and the listening position, a time delay is given by a delay device 3 to correct them and the level is corrected by an amplifier 5 to obtain the location sense.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stereo reproduction device that provides a good sense of localization to a wide listening position in a near-field sound field of a speaker.

[Conventional technology]

In general, a two-channel stereo playback device works best in a somewhat heated position, such as in front of the center of the two speakers, for example, where the two speakers and the listening position are at the vertices of an equilateral triangle. A sense of localization (
It is possible to obtain positional perception of the sound image generated by stereo reproduction) and a sense of presence.

This is because the sense of localization of a sound image is obtained by the relationship between the sound pressure difference between both ears and the time difference. in this case.

When the distance between the speakers and the listening position is large, there is little disturbance in the relationship between the sound pressure difference and time difference between the ears due to the difference in path length from the two speakers to the listener, so a good sense of localization can be achieved over a relatively wide range. can get. However, as the distance between the speakers and the listening position becomes smaller, the disturbances in the sound pressure difference and time difference between the two ears due to the difference in path length to reach the listener become less pronounced. It will be limited to. In such a case, if an attempt is made to obtain a good sense of localization in areas other than the center, the position where a good sense of localization can be obtained can be moved by controlling the sound pressure difference and time difference of the left or right channel signals.

[Problem that the invention seeks to solve]

However, when two sound sources emit sound at the same time, the human ear localizes the sound source in the direction in which the sound arrives. There is a characteristic of so-called advance sound localization, and it is actually difficult to move the position where a sense of localization can be obtained.

[Means for solving problems]

In order to solve these problems, the present invention provides speakers for left and right channels that have directivity in the front direction.
A speaker whose directivity is directed from the right channel speaker position to the left channel speaker listening position, a speaker whose directivity is directed from the left channel speaker position to the right channel speaker listening position, and a speaker whose directivity is directed from the right and left channel speaker positions. Each of the speakers is configured with outward facing speakers, and is provided with means for controlling the amplitude and phase of the signals input to these speakers.

[Effect]

The sound waves from each speaker are combined to expand the localization range of the sound image.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, 1 is the right channel signal input terminal, 2, 12
is a polarity inverter, 3, 11 is a delay device, 4-6, 13-15
7 to 9 are amplifiers, 16 to 1B are speakers, 10 is a left channel signal input terminal, 19 to 21 are listening positions, 22.
23 represent the main axes of acoustic radiation of the right channel and the left channel, respectively.

Figure 2 shows the configuration of the left channel speaker, with θ
1 is the installation angle on the outside in the forward direction, and θ2 is the installation angle on the inside in the forward direction. Each speaker is rotatable around a vertical axis, and the right channel speaker has a similar structure.

Focusing on the right channel signal in the device configured in this way, the difference in the level of υ distance attenuation is due to the difference between the path length between the speaker 9 and the listening position 21 and the path length between the speaker 17 and the listening position 210. Therefore, in order to correct this, the amplifier 6 is adjusted and a sound wave is emitted toward the listening position 21. Further, the speaker T is directed slightly outward from the listening position 19, and the amplifier 4 is adjusted so that in-head localization occurs at the listening position 19. In addition, speaker 8 and listening position 190
There is a distance attenuation and a time difference due to the difference in the path length between the speakers 16 and the listening position 19, so in order to compensate for this, the delay device 3 provides a time delay, and the amplifier 5 corrects the level. so that a sense of localization can be obtained.

Next, focus on the left channel, and do the same with amplifier 1.
3. Amplifier 15. Amplifier 14. Adjust the delay device 11.

The effectiveness of this invention at each listening position is as follows. At the listening position 19, first, the sound waves from the speakers 7 and 9 arrive at the same time, and they interfere with each other to form valleys in the directivity pattern.The level of unnecessary sound from the speaker 9 decreases, and the sound waves are opposite to the listener's ears. Because the phase signal is incident, the listener localizes a low-volume sound image in his or her head. However, immediately after that, a sound with a louder volume than this sound is heard from the speakers 8 and 16, and the listener localizes the sound image between the speakers 8 and 16.

On the other hand, although the sound from the speaker 17 is comparable to the sound from the speaker 16, it arrives with a delay of 1 ms or more, so it is not detected due to the effect of advance sound localization. Speaker 1
The sound from 8 is heard at listening position 21 depending on the directional characteristics of the speaker.
Since the sound is radiated to the outside of the sound source, its magnitude can be ignored as a direct sound at the listening position 19. At the listening position 20, the sound from the speakers 9 and 16 can be heard first.

The listener localizes the sound image by this. However, the sounds from the speaker T and the speaker 18 are radiated to the outside of all listeners due to the directional characteristics of the speakers, so they cannot be heard as direct sounds. The sounds from the speakers 8 and 17 that arrive next arrive after a delay of 1 ms or more, so they are not detected due to the effect of advance sound localization.

At the listening position [21], first, sounds from the speakers 16 and 18 arrive at the same time, interfere with each other, and form valleys in the directivity pattern. A signal of opposite phase enters the ear. However, immediately after that, a louder sound from the speakers 9 and 17 is heard, and the listener localizes the sound image between the speakers 9 and 17. On the other hand, although the sound from the speaker 8 has the same volume as the sound from the speaker 9, it arrives with a delay of 1 ms or more, so it is not detected due to the effect of advance sound localization. The sound from the speaker 7 is radiated to the outside of the listening position 19 due to the directional characteristics of the speaker.

At the listening position 21, the volume is negligible as a direct sound.

As a result, at listening position 19, speaker 8 and speaker 16
A sound image is localized by the sound from the speakers 9 and 16 at the listening position 20, and by the sounds from the speakers 9 and 17 at the listening position 21. Since the sounds from the speakers 8 and 17 are delayed by υ compared to the original input signal, the sounds from the speakers 9 and 17 are delayed by υ compared to the original input signal.
It has the same effect as the sound of No. 16, and the sound image is localized at the listening positions 19 and 21 in the same way as the listening position 20. That is, the sound image is localized even outside the speaker center line in the same state as when listening on the speaker center line in conventional two-channel stereo.

Figures 3 and 4 show a device to which this invention is applied.

This is an example of a subjective evaluation test result of a conventional device. Figure 3 shows the case of the central listening position (listening position 20 in Figure 1), the horizontal axis of the figure is the actual sound source position when sound is collected, and the vertical axis is the localization position. υ, L60, R60 are It shows 0.6rn on the left side + 0.6m on the right side. The circle marks are the results obtained by the conventional two-channel stereo reproduction device, and the square marks are the results obtained by the device of the present invention.If the test result is on the dashed-dotted line in the 45-degree line direction in the figure, it means that the test result is good. FIG. 4 shows the case of the listening position on the right side (listening position 19 in FIG. 1). The results of this invention are closer to the dashed-dotted line in the diagonal direction of 45 degrees than the results of the conventional two-channel stereo reproduction device, indicating its effectiveness.

As is clear from this result, the present invention can provide a good sense of localization to a wide listening position in the near-field sound field of the reproduction speaker. Furthermore, although the listening positions are divided into three, in reality they can be considered to change smoothly, and it is sufficient if the listener is inside the listening positions 19 and 21.

Figure 5 shows an example of controlling the installation angle of speakers 7 to 9 or speakers 16 to 18 (the angle indicated by symbol θ in Figure 2) by remote control. The left channel system has a similar configuration.

In the figure, 30 is a remote control system, 311 to 31n are operating units, 32 and 36 are control units, 33 is a modulation unit, 34 is a transmitting unit,
35 is a receiving section, 3T is an amplifier, 38 is a motor, 39 is a drive transmission system, and 40 is a speaker system.

The remote control system 30 is used to adjust the installation angles of the speakers 7 to 9 to positions in front of the speakers that are distant from the speaker position. The operation unit 31 is an input means such as a numeric keypad, and the number of key presses corresponds to the rotation angle of the speaker. This operation section has various keys and can also be used to adjust the volume, etc. The control unit 32 gives an identification code for each function key to the input signal (adjustment i) from the operation unit 31, and the modulation unit 33 modulates the output from the control unit 32.
I'll send it out. The transmission signal is, for example, infrared light, and in this case, the transmitter 34 serves as an infrared light emission source. speaker system 4
0 is built into the speaker housing. Receiving section 35
Then, the signal sent from the remote control system 30 is received, demodulated, and converted into a signal consisting of an identification code and an adjustment amount. The control unit 36 determines the identification code and outputs a volume signal or drive control signals 81 to S3. The signal S1 is for driving the motor 38 for rotating the speaker 7, and the signal 32. Although S3 is not shown, the speakers 8,
It is used for driving the motor to rotate 9.

Note that speakers 5 to 7 and speakers 16 to 1B are the sixth
As shown in the figure, even if they are installed in two parts and only the speaker 8 is rotated, the installation angle θ1. θ2 can be changed.

In this manner, by rotating the speaker by remote control, continuous adjustment can be performed in real time, and changes before and after adjustment can be clearly identified, allowing for smooth adjustment.

〔Effect of the invention〕

As explained above, the present invention provides three speakers facing the front, inside, and outside for one channel, and has a similar configuration for the other channel, and adjusts the amplitude and phase of the signal supplied to each speaker. So,
This has the effect that a good sense of localization can be obtained for a wide listening position in a near-field sound field.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a perspective view showing an example of a speaker, FIGS. 3 and 4 are graphs showing subjective evaluation results at the center and right listening positions, FIG. 5 is a block diagram of the speaker rotation device, and FIG. The figure is a perspective view showing another embodiment of the speaker. 2.12...Polarity inverter, 3.11...Delay device, 4~6.13~15...Φ・Amplifier, 7~9, 16~
18so...Speaker, 19-21...Listening position,
32.36...Control unit, 33...Modulation unit, 34
...Transmission section. 35...Receiving part, 38...Motor, 39...
・Drive transmission system. Patent applicant: Nippon Telegraph and Telephone Corporation Agent Masaki Yamakawa (and one other person) Figure 5 30 Figure 6

Claims (2)

[Claims] (1) a first right channel speaker for reproducing an amplified right channel signal, a second right channel speaker for reproducing a delayed right channel signal, and a second right channel speaker for reproducing an amplified and phase inverted right channel signal; The right channel system consists of the right channel speaker of 3, and the right channel system has the same configuration as the right channel system, but the original input signal is for the left channel,
It consists of a left channel system in which the three types of speakers are the first, second, and third left channel speakers, where the first speaker faces toward the inside of the front, the second speaker faces toward the front, and the third speaker faces toward the front. The speakers are directed toward the outside of the front, and the amplification amount and phase delay amount are set so that the audible sound image is localized in the range from the front front of the second right channel speaker to the front front of the second left channel speaker. Characteristic stereo playback device. (2) a first right channel speaker for reproducing the amplified right channel signal, a second right channel speaker for reproducing the delayed right channel signal, and a second right channel speaker for reproducing the amplified and phase inverted right channel signal; The right channel system consists of the right channel speaker No. 3, and the right channel system has the same configuration as the right channel system, but the original input signal is for the left channel,
Consisting of a left channel system in which the three types of speakers are first, second, and third left channel speakers, an adjustment mechanism that independently controls the directivity direction of each speaker, and means for remotely controlling this adjustment mechanism. The first speaker faces the front inside, the second speaker faces the front front, the third speaker faces the front outside, and the amplification amount and phase delay amount are set in front of the second right channel speaker. 1. A stereo playback device characterized in that a listening sound image is localized in a range from the front to the front front of a second left channel speaker.