JPH01223895A - Acoustic reproducing device - Google Patents

Abstract

PURPOSE:To suppress the deviation of the frequency characteristic of reproduction environment by giving an output of a noise generating circuit generating a low frequency range to 1st and 2nd speakers to apply reproduction, collecting sound by a microphone provided at a listening position and adjusting the phase of an acoustic signal reproduced from the 2nd speaker in response to the level of the low frequency range. CONSTITUTION:Plural speakers are divided into two groups (1st and 2nd) F, R, and an output of a noise generating circuit 5 generating a low frequency range is given to the speakers F, R to attain reproduction. On the other hand, a microphone 12 is provided at the listening position and the phase of the acoustic signal reproduced by the speakers R of the 2nd group is varied and adjusted corresponding to the level of the low frequency range collected by the microphone 12. Thus, the deviation of the frequency characteristic of the reproduction environment is suppressed or the frequency characteristic desired by a listener is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is suitably implemented as a vehicle, and more specifically, the present invention adjusts the phase of the sound emitted from a plurality of speakers, especially in the bass range, and performs sound reproduction. The present invention relates to a sound reproduction device that can obtain different acoustic characteristics depending on the reproduction environment in which the sound is played, and sound 1iF characteristics according to the listener's preference.

Conventional technology In in-vehicle sound reproduction devices, due to the acoustic characteristics of the vehicle interior, depending on the listening position, mutual interference may occur between the sound 9g signals reproduced from multiple speakers, making it difficult to actually hear the sound. The resulting sound pressure level will deviate from the frequency of the reproduced sound, and the level in the bass range will particularly decrease.

For example, in the case of a so-called 3D system, methods to eliminate such mutual interference in the bass range include inverting the phase of the acoustic signal reproduced from the woofer, or installing speakers in the front and rear of the passenger compartment. If installed, playback is performed with the signals from the rear speakers in reverse phase.
It was.

Problems to be Solved by the Invention In the above-mentioned prior art, it is always difficult to completely match the phase of the entire audio frequency band, depending on the vehicle type, the number of passengers, etc., and the interior environment of the vehicle. In addition, if the speakers used are so-called full-range speakers, an unnatural feeling may occur in the mid-to-high range when the notes are played in reverse phase as described above. It is difficult.

An object of the present invention is to adjust the phase of sound IF signals reproduced from a plurality of speakers in accordance with the reproduction environment in which sound is reproduced, and to eliminate deviations in frequency characteristics due to acoustic characteristics specific to the reproduction environment. Alternatively, it is an object of the present invention to provide a sound reproduction device capable of reproducing acoustic characteristics according to the listener's preferences.

Means for Solving the Problems The present invention divides a plurality of speakers into two groups, a first and a second group, applies the output of a noise generation circuit that generates at least a low frequency range to these speakers, and provides the speakers at a listening position. The sound reproduction device r is characterized in that it is provided with means for changing and adjusting the phase of the speakers of the second group in accordance with the level of the bass range picked up by the microphone.

Effect 1 According to the present invention, a plurality of speakers are divided into two groups, a first and a second group, and the output of a noise generation circuit that generates a low frequency range is supplied to these speakers for reproduction. On the other hand, a microphone is provided at the listening position, and the phase of the acoustic signal reproduced from the second group of speakers is changed and adjusted in accordance with the level of the bass range picked up by the microphone.

Therefore, it is possible to change the phase of the second group of speakers in response to different acoustic characteristics depending on the reproduction environment, suppressing mutual interference between the reproduced sounds of the first and second speakers at the listening position, In this way, deviations in the frequency characteristics of the reproduction environment can be suppressed, or the frequency characteristics desired by the listener can be obtained.

Embodiment 1 I21 is a block diagram showing the configuration of a sound reproduction device 1 according to an embodiment of the present invention. Two groups of speakers are provided in the vehicle cabin 10, one on the front side and the other on the rear side.The front side, for example, the instrument panel 2, has two groups of speakers on the left and right. 5U L 7 F h '1-7. = )h
'fit It 91.7 and 911. ,.

For example, on the rear tray 3 on the opposite side of the vehicle interior 10, two left and right speakers (generally referred to as R) are provided. These speakers F and R are so-called full-range speakers that can reproduce the entire audible frequency band.

Speaker F has the sound (
The acoustic signal 4g from the S signal source 4 or the so-called pink noise from the noise generating port n5 is applied to the power amplifier 6 fr. The sound C signal or pink noise which is switched and derived by the changeover switch S1 has its phase adjusted by a phase shifter 7 and is sent to a speaker R via a power amplifier 8.
given to.

The phase shifter 7 may be a digital signal processing device called DSP, or may be configured using an analog method in which a volume is rotated by a motor.

In order to measure the acoustic characteristics of the vehicle interior 10, a microphone 12 is provided, for example, in the driver's seat 11 serving as a listening position, and the output of the microphone 12 is applied to a bandpass filter 14 via an amplifier 13. This bandpass filter 14 has a plurality of pass frequency bands, and one of the bands is selected by a processing circuit 15 implemented by a microcomputer or the like. The output No. 13 of the microphone 12 for each frequency band selected in this way is included in the processing circuit]5, and the processing circuit F! ? ! 1
5 adjusts the amount of change of the phase shifter 7 according to its output.

In the sound reproduction device 1 configured as described above, the acoustic characteristics of the vehicle interior 10 are adjusted as follows.
Sign. In other words, first turn the selector switch SL to the noise generation time l.
Conductive to the i'35 side, at least in the bass range (50 to 150
The pink noise containing the 1(z) component is transmitted to the speaker F.
, R respectively.

The reproduced pink noise is collected by the microphone 12, and the bandpass filter 14 divides the low frequency component into, for example, three frequency bands j1 to f3.
A signal representing the sound pressure level in each frequency band is provided to the processing circuit 15.

The detection results detected in this way are shown in, for example, Figure 2 (
1), the processing circuit 15 adjusts the amount of change in the phase shifter 7 based on this detection result, and for example, the second
As shown in FIG. 2, the output sound pressure level of each frequency band f1 to f3 is 1ulled so as to be flat. Speaker F is close to the listener, so it is easier to obtain a natural hearing sensation by changing the phase of speaker R than by changing the phase of speaker F. When the adjustment is completed in this way, switch S1 is turned By switching to the signal source 4 side, an acoustic signal whose phase has been changed by the phase shifter 7 in accordance with the acoustic characteristics of the vehicle interior 10 is reproduced from the speaker R.

In this way, even if the playback environment differs depending on the vehicle model or the number of occupants, it is possible to eliminate deviations in frequency characteristics and achieve good sound reproduction without feeling the lack of low frequencies as mentioned in the related section of the conventional technology. It can be performed.

Further, as shown in FIG. 2 (3), the phase can be adjusted to obtain frequency characteristics according to the listener's preference. In this way, the sound reproducing device 1 according to the present invention can correspond to various acoustic characteristics of the vehicle interior 10, and therefore can be installed in a wide range of vehicle types regardless of the type of vehicle, and can be installed at the so-called manufacturing stage of the vehicle. , not only genuine products that are standard equipment, but additional equipment can be added even after manufacturing. Furthermore, as mentioned above, it is not limited to the case where the left and right channel speakers are arranged in the front and rear of the vehicle interior 10, respectively.
Similar effects can be obtained even when used in a so-called 3D system and configured to change the phase of the woofer.

Effects of the Invention As described above, according to the present invention, the output of a noise generation circuit that generates at least a low frequency range is given to the speakers divided into two groups, the first and the second, to perform reproduction, and the reproduced sound is listened to. The sound is collected by a microphone placed at the
Since the phase of the acoustic signal reproduced from the second group of speakers is changed and adjusted according to the level of the bass range, even for acoustic characteristics that differ depending on the reproduction environment,
Mutual interference between the sounds reproduced by the speakers can be suppressed, and deviations in the frequency characteristics of the reproduction environment can be suppressed, or frequency characteristics desired by the listener can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a sound reproduction device 1 according to an embodiment of the present invention, and FIG. 2 is a graph showing the frequency characteristics of the sound pressure level in the vehicle interior 10 due to phase changes. 1... Sound reproduction device, 4... Sound signal source, 5...
Noise generating circuit, 6.8... Power amplifier, 7... Phase shifter, lO... Vehicle interior, 11... Driver's seat, 12... Microphone, 171... Bandpass filter, 15...
・Processing circuit, F. R...Speaker, Sl...Selector switch agent
Patent attorney number of strokes Keiichi = 8-

Claims (1)

[Scope of Claims] A plurality of speakers are divided into two groups, a first and a second group, and the output of a noise generation circuit that generates at least a low frequency range is applied to these speakers, by a microphone provided at a listening position. A sound reproducing device comprising means for changing and adjusting the phase of the second group of speakers in accordance with the level of the collected bass sound.