JPH03214894A - Acoustic signal reproducing system - Google Patents

Abstract

PURPOSE:To prevent a virtual sound source position from being moved even when a listener moves by receiving an acoustic signal transmitted from a transmitting means, finding a transfer characteristic, processing it and supplying to a headphone unit. CONSTITUTION:A sound source device 20 receives reference signals S1 and S2 for detecting a head part position transmitted from transmitting parts 18L and 18R of a headphone device 10 side by a receiving part 21. Based on a receiving output by the receiving part 21, a transfer characteristic is operated by an acoustic signal processing circuit 26 and signal processing which is made to correspond to the change of the transfer characteristic with the movement of a listener and the rotation of the head part in real time is performed to acoustic signals SL and SR of left and right channels. Then, the acoustic signals SL' and SR' of the left and right channels processed by the circuit 26 are transmitted to a receiving part 11. The receiving part 11 supplies received signals to headphone units 15R and 15L of the left and right channels. Thus, natural sound image localization feeling of which a virtual sound source does not move can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an audio signal reproducing system for reproducing an audio signal using a headphone device. B. Summary of the Invention The present invention provides an audio signal reproducing system for reproducing an audio signal using a headphone device, which includes a transmitting means for transmitting a reference signal for detecting the position of a listener's head, and a transmitting means for receiving the audio signal and supplying the received audio signal to a headphone unit. A receiving means is provided on the headphone device side, a receiving means for receiving a reference signal for head position detection transmitted from the transmitting means on the headphone device side is provided on the sound source device side, and a transfer characteristic is determined based on the received output by the receiving means. an acoustic signal processing means for calculating and processing the left and right channel acoustic signals respectively based on the transfer characteristics;
By providing transmitting means for transmitting the left and right channel sound signals processed by the sound signal processing means to the receiving means on the headphone device side, wireless pinaural reproduction is made possible.

C. Prior Art Conventionally, as in the case of a headphone device that reproduces acoustic signals using a headphone unit, a pair of headphone units supported in correspondence near the pinnae of both ears is attached to the listener's head. The pinaural method is known as a method that improves the sense of direction of the sound image and the sense of localization outside the head when reproducing acoustic signals using the Pinaural method. The sound reproduction system that uses this pinaural method is
For example, as described in Japanese Patent Publication No. 53-283, predetermined signal processing is performed on the acoustic signal reproduced by the headphone device 1 in advance.

Here, the sense of direction of the sound image, the sense of localization outside the head, etc. are determined by the volume difference, time difference, phase difference, etc. between the sounds heard by the left ear and the right ear. The above-mentioned signal processing refers to, for example, when reproducing sound using a speaker device placed at a distance from the listener, the distance from the sound source, that is, the speaker device to the left and right ears of the listener, is adjusted based on the difference in distance and the proximity of the listener's head. This is signal processing that produces an acoustic effect equal to the acoustic effect caused by reflection, diffraction, etc., in the acoustic output reproduced by a headphone device. Such signal processing is performed, for example, by convolving and integrating the impulse responses corresponding to the above-mentioned acoustic effects with the acoustic signals for the left ear and the right ear. By the way, when sound is reproduced using a speaker device placed at a distance from the listener, the absolute position of the sound image does not change even if the listener moves or rotates the direction of the head. , the relative direction and position of the sound image perceived by the listener changes. On the other hand, when playing back sound using a pinaural method using a headphone device, when the listener rotates the direction of the head, the headphone device also rotates with the head, so the relative sound image perceived by the listener is The direction and position of the object do not change.

When performing binaural playback using a headphone device in this way, a sound field is formed inside the listener's head due to differences in the displacement state of the sound image in response to changes in the direction of the listener's head, and the sound image is distorted. There are reconnaissance situations in which it is difficult to localize the sound in front of the listener, and moreover, the sound image in front of the listener rises.

Therefore, conventionally, Japanese Patent Application Laid-open No. 42-227 and Japanese Patent Publication No. 54
As described in Publication No. 19242, by detecting changes in the direction of the listener's head and changing the signal processing state based on the detection results, a headphone device can achieve a good sense of forward localization. An acoustic signal reproduction system has been devised to achieve this. In such an acoustic signal reproduction system, a direction detection device such as a so-called gyro compass or a magnetic needle is disposed on the listener's head.

Then, based on the detection result by the direction detection device, the level adjustment circuit, delay circuit, etc. that process the acoustic signal are controlled, similar to the sound reproduction by the subica device placed away from the listener. Problem to be Solved by the Invention However, in the conventional pinaural playback system in which a headphone device is equipped with a direction detecting device such as a gyro compass as described above, A good sense of sound image localization can be obtained by controlling the content of signal processing applied to the acoustic signal according to changes in the direction of the listener. Because it was large and heavy, it was necessary to adopt a stationary configuration with a fixed listening position.

In other words, direction detection devices such as the gyrocompass mentioned above have the problem of being too large and heavy to be worn together with headphone devices on the head of a freely moving listener. Not suitable for practical use. In conventional pinaural playback systems, the listener must wear a headphone device on his or her head that receives an acoustic signal from the sound source device via a signal cable, so if the listener is configured to be mobile, Moreover, the movement of the listener is restricted by the signal cable.

Therefore, in view of the conventional situation as described above, the present invention has been developed by attaching a headphone device to the head of a freely moving listener.
The purpose of this invention is to provide an acoustic signal reproduction system that can perform pinaural reproduction of an acoustic signal wirelessly using a headphone device, with the aim of achieving stable pinaural reproduction. E! Means for Solving the Problem In order to achieve the above-mentioned object, the acoustic signal reproduction system according to the present invention includes a transmitting means for transmitting a reference signal for detecting the position of the listener's head, and a transmitting means for receiving the acoustic signal. a headphone device comprising a receiving means for supplying the signal to the headphone unit;
A receiving means for receiving a reference signal for head position detection transmitted from the transmitting means on the headphone device side, and a transfer characteristic is calculated based on the reception output of this receiving means, and a transfer characteristic is calculated for the left and right channels based on the transfer characteristic. A sound source device comprising an acoustic signal processing means for processing each acoustic signal, and a transmitting means for transmitting the left and right channel acoustic signals processed by the acoustic signal processing means to the receiving means on the headphone device side. It is characterized by F. Effect In the acoustic signal reproduction system according to the present invention, the sound source device receives a reference signal for head position detection transmitted from the transmitting means on the headphone device side using the receiving means, and based on the reception output by the receiving means. , the acoustic signal processing means calculates the transfer characteristics and processes the left and right channel acoustic signals respectively. Then, the left and right channel audio signals processed by the audio signal processing means are transmitted by the transmitting means to the receiving means on the headphone device side. Further, on the headphone device side, a reference signal for detecting the position of the listener's head is transmitted by the transmitting means to the receiving means on the sound source device side, and an acoustic signal transmitted from the transmitting means on the sound source device side is received. The signal is received by the means and supplied to the headphone unit.

G. Example Hereinafter, an example of the audio signal reproduction system according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the acoustic signal reproduction system according to the present invention includes a hesodophone device 1 (10) and a sound source device (20) that wirelessly transmit and receive signals.

The headphone device (10) includes the sound source device iF (2
0), which receives a stereo acoustic signal optically transmitted, for example. The received output from this receiving section (l1) is detected by a detection circuit (12) and supplied to a multiplexer (13). This multiplexer (
l3) forms left and right channel acoustic signals S L' + S II' from the detection outputs of the detection circuit (l2). Left and right channel audio signals S L ′ + S I1′ obtained by the multiplexer (13)
is the above amplifier (14L). (14R) is supplied to the henodophon unit (15L) (15R). The headphone device (10) also includes reference signals S, S! for detecting the position of the listener's head. first and second forming
Reference signal oscillator (16L). (16R) is provided. These reference signal oscillators (16L). (16R), the reference signal S+, Si formed by the synchronization adjustment section (l
7), the first and second
is supplied to the transmitting sections (17L) and (17R). The first and second transmitting sections (17L) and (17R) transmit reference signals S1, S, for detecting the head position of the listener. Here, the first and second transmitting sections (17L) . (
17R) are each configured with an ultrasonic speaker, and transmit the reference signal S.17R) for position detection. ,S. As shown in A and B of FIG. 2, a burst wave in which ultrasonic waves of a predetermined level are intermittently transmitted at a predetermined time interval, or
An ultrasonic wave whose phase can be detected is transmitted, such as a so-called level modulated wave whose level fluctuates in a predetermined manner at a predetermined period.

In this embodiment, the headphone device (10) includes:
As shown in Figure 3, a pair of hesodophone units (15L) and (15R) are installed near the listener's left and right auricles.
The headband (1) supports the listener's head (M
). In addition, in the above-mentioned band (1),
2 with protruding support arms (3L) and (311)
Sliders (4L). (4R) is slidably attached to the first and second transmitting sections (18L),
(18R) is the support arm (3L). (3R)
It is provided at the tip of the. That is, the first and second transmitting sections (18L) . (18R) is a slider (4L) that is slidably attached to the headband (1).
)． (4tl) with a protruding support arm (3L)
), by being provided at the tip of (3R),
The headband (1) and a pair of headphone units (15L). (151?) The above support arm (3L). (3R). Further, at the top of the headband (1), there is provided a support arm (3) having the receiving section (11) at its tip.
has been erected.

The receiving section (l1) and the first and second transmitting sections (18L)
, (18R) are supported by the support arms (3), (3L), and (3R) at positions distant from the headphone body, so even if the listener moves or rotates his/her head, The acoustic signal transmitted from the sound source device (20) can be stably and reliably received by the receiving section (l1) without being in the shadow of the listener's head, and the first and second 2 transmitter (18L),
(18R), the reference signals St, St for position detection can be stably and accurately transmitted.

Note that the first and second transmitting sections (18L) . (1
8R) can be adjusted to the optimum position for detecting the reference signal for position detection by sliding the slider <4L), (411) along the headband (1).

For example, the headband (1) may be attached to the listener's head (M
) and supported near the listener's left and right auricles (15I, ), (15
The position of the headphone unit (R) depends on the shape and size of the listener's head (M) and varies from person to person.
5L), (15R), the first and second transmitting sections (18L) . Adjust the position of (18R).

Further, as shown in FIG. 1, the sound source device (20) includes:
The first and second transmitting sections (18L) on the headphone device (10) side. A receiver (2) receives the reference signals St, Sz for position detection transmitted from (18R).
1). The received output by this receiving section (21) is
The wave is detected by the detection circuit (22) and sent to the position detection circuit (23).
).

Here, the received output of the reference signals Sl, St for position detection by the receiving section (21) is $1°. As shown in B and C in FIG. 2, S2 includes the receiving unit (21) and the first and second transmitting units (
l81, ), (18R), that is, the time delay ΔT according to the rotational angular position of the listener's head (M)
It will have the following.

The position detection circuit (23) calculates the rotation angle θ of the head (II) from the information of the time delay ΔT, and obtains current position information of the head (M) with respect to a desired virtual sound source position. demand.

The current position information of the listener's head (gate) obtained by the position detection circuit (23) is supplied to the control 11 circuit (21).

The acoustic signal reproducing apparatus of this embodiment includes a storage circuit (25) that stores transfer characteristic information for each predetermined angle indicating the transfer characteristic from the virtual sound source to both ears of the listener.

The control circuit (21) then controls the angle calculation circuit (
Based on the current position information calculated in step 20), transfer characteristic information corresponding to the current position is read out from the storage circuit (25), and this transfer characteristic information is sent to the acoustic signal processing circuit (26).
supply to.

The acoustic signal processing circuit (26) includes an acoustic signal supply s
(27) left channel and right channel audio signals SL. SR is supplied.

Note that the audio signal supply source (27) is a device that outputs predetermined left channel and right channel audio signals SL, SR, and is, for example, a variety of recording disk playback devices, recording tape playback devices, or a radio wave reception device. equipment, etc.

The acoustic signal processing circuit (26) provides a signal that imparts predetermined transfer characteristics from the virtual sound source to both ears of the listener to the left channel and right channel acoustic signals SL and SR sent from the acoustic signal supply source (27). It is a circuit that performs processing,
First to fourth signal processing units (28a), (28a) to which transfer characteristic information obtained by the control circuit (24) is supplied;
28b). (28c) and (28d). Each of these signal processing units (28a), (28b)
．． (28c), (28d), the above control circuit (
24) Based on the transfer characteristic information supplied from ,S. The impulse response that expresses the transmission characteristics to each ear of the listener when playing music is set.

That is, the first signal processing section (28a) generates an impulse response (h++++(
t. θ)}. The second signal processing section (28b
) is an impulse response [
Set h*L(t, θ)}. The third signal processing unit (28C) sets an impulse response (ht←1θ) that expresses the transfer characteristics of the sound reproduced from the left channel sound signal SL to the right ear. The fourth signal processing section (28d) includes a left channel acoustic signal S.
An impulse response {hLL(t, θ)} expressing the transfer characteristics of the sound reproduced by L to the left ear is set.

The right channel acoustic signal S, is transmitted to the first and second signal processing sections (28a). (28b). The first signal processing section (28a) performs signal processing on the right channel acoustic signal S by convolution integral of the impulse response (hB(L, θ)}. In step 28b), the right channel acoustic signal S8 is subjected to signal processing by convolution integration of the impulse response (hxt(t, θ)).

Furthermore, the left channel acoustic signal S is sent to the third and fourth signal processing sections (28c) and (28d). The third signal processing section (28c) performs signal processing on the left channel acoustic signal SL by convolution integration of the impulse response {hci(t.θ)}.

Further, the second signal processing section (28d) performs signal processing on the left channel acoustic signal SL by convolution integral of the impulse response [htL(t, θ)}. The output signals of the first signal processing section (28a) and the third signal processing section (28c) are then output to the right side adder (29R).
) and are added together. This adder for the right side (2
The output signal of the right channel correction circuit (30R)
) is supplied to the mixer circuit (31).

Further, the output signals of the second signal processing section (28b) and the fourth signal processing section (28d) are output from the left side adder (29L).
) and are added together. This adder for the left side (2
The output signal of the left channel correction circuit (30L)
) is supplied to the mixer circuit (3l). The mixer circuit (31) includes a correction circuit (
30L) and (30R) from the acoustic signal processing circuit (26), the acoustic signals SL'+SR' whose transfer characteristics have been processed are mixed and supplied to the transmitter (32). The transmitter (32) is, for example, an optical transmitter that uses infrared rays as a carrier wave, and is configured to receive left and right channel acoustic signals S. ,S. The infrared rays are modulated with a mixed signal and transmitted optically. That is, the sound source device (20) receives reference signals S, S. is received by the receiving section (21), and based on the reception output from the receiving section (2), the acoustic signal processing circuit (26) calculates the transfer characteristics to determine the movement of the listener and the head (M). Signal processing that corresponds to changes in transfer characteristics due to rotation in real time is performed on the left and right channel acoustic signals SL and S.
Apply to l. Then, the left and right channel sound signals S L' + processed by this sound signal processing circuit (26)
S l' is optically transmitted by the transmitter (32) toward the receiver (11) on the headphone device (10) side. The headphone device (10) transmits the reference signals St, St for detecting the position of the listener's head to the transmitter (18L).
), (18R) to the receiving section (21) on the sound source device (20) side, and the acoustic signal SL''.s.' transmitted from the transmitting section (32) on the sound source device (20) side. The signal is received by the receiving section (11) and supplied to the left and right channel hesodophone units (15L) and (15R).

The left and right channel audio signals SLZSR' received by the receiver (l1) on the headphone device (10) side are transmitted to the audio signal processing circuit (26) on the sound source device (20) side.
Since the headphone unit (15L) is subjected to signal processing that corresponds in real time to changes in the transfer characteristics accompanying the movement of the listener and the rotation of the head (M), the headphone unit (15L),
(15R) enables pinaural reproduction. For example, as shown in A, B, and C of Fig. 4, which show the relative positional relationship between the virtual sound source and the listener, A pair of subica units (SL) are installed in front of the vehicle.
)． (SR) provides a good sense of external localization, forward localization, and backward localization in which the virtual sound source does not move, as in the case of reproducing an acoustic signal.

Here, in FIG. 4, a listener (P) is connected to a pair of stereoscopic devices (SL). (SR) That is, A for the virtual sound source.
B shows a state in which the listener (P) approaches the virtual sound source from the position shown in FIG. There is. In the acoustic signal reproduction system according to the present invention, as described above, the sound source device (20) side performs signal processing that corresponds in real time to changes in transfer characteristics accompanying movement of the listener and rotation of the head (M). By using the signal processing circuit (26), it is possible to obtain a good sense of localization outside the head and a sense of forward localization without moving the virtual sound source, and it is compatible with any of the states A, B, and C in Fig. 4 above. Pinaural playback can be performed wirelessly. H. Effects of the Invention As described above, in the acoustic signal reproduction system according to the present invention, the reference signal for detecting the position of the listener's head is transmitted by the transmitting means provided in the headphone device, so that the sound source device side can detect the head position of the listener. The receiving means receives a reference signal for detecting the head position transmitted from the side transmitting means, and based on the reception output of the receiving means, the acoustic signal processing means deduces the transfer characteristics and generates the left and right channel acoustic signals. can be processed respectively. Then, the sound source device transmits the left and right channel audio signals processed by the audio signal processing means to the receiving means on the headphone device side by means of the transmitting means, so that the headphone device side receives the left and right channel acoustic signals processed by the sound signal processing means from the transmitting means on the sound source device side. By receiving the transmitted acoustic signal by the receiving means and supplying it to the phone unit, the virtual sound source position does not move even if the listener moves, and an extremely natural sound image localization feeling can be obtained. Pinaural playback can be performed wirelessly.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically showing the configuration of the acoustic signal reproduction system according to the present invention, and FIG. Time chart showing discharge,
FIG. 3 is an external perspective view showing a state in which a listener wears the headphone device in the audio signal reproduction system on the head;
FIG. 4 is a plan view showing the relative positional relationship between a virtual sound source and a listener to explain the operation of pinaural reproduction by the acoustic signal reproduction device 1. 10) ・・・・・・・・・・・・ 11) ・・・・・・・・・・・・ 15L) . (15R) ...18L) ,
(18R) 20) 21) 23) 24)・・・・・・・・・・・・ (25)・・・・・・・・・・・・ (26)・・・・・・・・・・・・ (27)・・・・・・・・・... (32) ...... Headphone device Receiving section on the headphone device side Headphone unit Transmitting section on the headphone device side Sound source device Receiving section on the sound source device side Position detection circuit system 1n circuit storage circuit Acoustic signal Processing circuit Acoustic signal supply source Transmitting unit on the sound source device side

Claims (1)

[Scope of Claims] A headphone device comprising a transmitting means for transmitting a reference signal for detecting a listener's head position, and a receiving means for receiving an acoustic signal and supplying it to a headphone unit; a receiving means for receiving a reference signal for head position detection transmitted from the transmitting means; a transfer characteristic is calculated based on the received output by the receiving means; and the acoustic signals of the left and right channels are respectively processed based on the transfer characteristic. and a sound source device provided with an acoustic signal processing means for processing the audio signals, and a transmitting means for transmitting the left and right channel acoustic signals processed by the acoustic signal processing means to the receiving means on the headphone device side. Sound reproduction signal system.