JP5817182B2 - Speaker device and electronic device - Google Patents

Description

  The present invention relates to a speaker device and an electronic apparatus.

  As a technique for preventing others from listening to sound, a parametric speaker using ultrasonic waves as a carrier wave has been developed. Since ultrasonic waves are highly directional, using a parametric speaker can form a sound field only in a specific direction, such as near the user.

  For example, in Patent Document 1, an ultrasonic transducer array including a plurality of ultrasonic transducers is used as a parametric speaker, and sound directivity is controlled by individually controlling the ultrasonic transducers. It is disclosed. Patent Document 1 also describes changing the frequency of a carrier wave in accordance with the distance to an area where audible sound is to be reproduced.

JP 2008-113190 A

  As the frequency of the carrier wave increases, the parametric speaker also increases the frequency at which the sound pressure is highest among the reproduced audible sounds. For this reason, if a plurality of frequencies are used as the carrier frequency, the quality of the audible sound can be improved. On the other hand, when a carrier wave having a plurality of frequencies is used, the average frequency of the carrier wave becomes high, which causes a problem that the power consumption of the speaker becomes high.

  The objective of this invention is providing the speaker apparatus and electronic device which can make the quality of an audible sound high as needed, and can suppress that power consumption becomes high.

According to the present invention, a plurality of parametric speakers to which a modulation signal obtained by modulating an audio signal into an ultrasonic band is input;
Based on the audio quality required for the audio signal, it is determined whether or not the frequency of the modulation signal is different between the plurality of parametric speakers, and based on the determination result, the frequency at each of the plurality of parametric speakers is determined. A frequency setting means for setting the frequency of the modulation signal;
Modulation means for generating the modulation signal of the set frequency;
With
The frequency setting means includes
When the voice quality is high, the frequency of the modulation signal is made different among the plurality of parametric speakers,
Provided is a speaker device in which when the voice quality is low, the frequency of the modulation signal is matched among the plurality of parametric speakers and lower than the highest frequency among the frequencies when the voice quality is high. .

  According to the present invention, an electronic apparatus having the above-described speaker device is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the quality of an audible sound can be made high as needed, and it can suppress that power consumption becomes high.

It is a figure which shows the function structure of the speaker apparatus which concerns on 1st Embodiment. It is a figure which shows how the sound pressure of the frequency of the sound to demodulate changes with the frequency of a modulation signal. It is a figure for demonstrating the effect of embodiment. It is a block diagram which shows the structure of the speaker apparatus which concerns on 2nd Embodiment. It is a figure which shows the 1st example of a structure of a people detection part. It is a figure which shows the 2nd example of a structure of a people detection part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

(First embodiment)
FIG. 1 is a diagram illustrating a functional configuration of the speaker device according to the first embodiment. The speaker device includes a frequency setting unit 120, a modulation unit 130, and a plurality of parametric speakers 140. The parametric speaker 140 receives a modulation signal obtained by modulating an audio signal in the audible range into an ultrasonic band. The frequency setting unit 120 acquires information indicating the voice quality required for the voice output from the parametric speaker 140. Then, the frequency setting unit 120 determines whether or not to change the frequency of the modulation signal among the plurality of parametric speakers 140 based on the acquired information indicating the voice quality. Then, the frequency setting unit 120 sets the frequency of the modulation signal in each of the plurality of parametric speakers 140 based on the determination result. The modulation unit 130 generates a modulation signal having a frequency set by the frequency setting unit 120. This modulated signal is input to each parametric speaker 140.

  FIG. 2 shows how the sound pressure at the frequency of the audio to be demodulated varies with the frequency of the modulation signal. As shown in this figure, as the frequency of the modulation signal increases, the frequency at which the sound pressure of the demodulated sound is maximized increases.

  For this reason, as shown in FIG. 3, when the frequencies of the modulation signals in the plurality of parametric speakers 140 are different from each other, the frequency dependence of the sound pressure of the demodulated sound is lowered. Therefore, the quality of the demodulated sound is increased.

  The speaker device is built in an electronic device, for example, a portable electronic device such as a portable communication terminal. For this reason, the parametric speaker 140 is also required to have low power consumption. Here, when the frequency of the modulation signal is increased, the impedance of the parametric speaker 140 is decreased, so that the power consumption of the parametric speaker 140 is increased.

  On the other hand, in the present embodiment, the frequency setting unit 120 varies the frequency of the modulation signal among the plurality of parametric speakers 140 when the required voice quality is high. Further, when the required voice quality is low, the frequency setting unit 120 matches the frequency of the modulation signal among a plurality of parametric speakers. Then, the frequency setting unit 120 sets the frequency at this time to be lower than the highest frequency among the frequencies when the voice quality is high. Therefore, the amount of power consumed by the parametric speaker 140 can be reduced. Note that the frequency setting unit 120 may lower the frequency of the modulation signal when the required voice quality is low than the average frequency when the voice quality is high.

  The parametric speaker 140 has vibration means for outputting sound waves, for example, an ultrasonic vibrator such as a piezoelectric vibrator. The plurality of parametric speakers 140 are arranged in an array, for example. The frequency setting unit 120 stores a basic resonance frequency of the ultrasonic transducer in advance, and selects a frequency that is an integral multiple of the basic resonance frequency. For example, when the required voice quality is low, the frequency setting unit 120 sets the basic resonance frequency as the frequency of the modulation signal. In addition, when the required voice quality is high, the frequency setting unit 120 sets the fundamental resonance frequency and a frequency N times the fundamental resonance frequency (where N ≧ 2 and an integer) to each modulation signal of the plurality of parametric speakers 140. Set as the frequency. The frequency setting unit 120 sets N in ascending order.

  The modulation unit 130 modulates an audio signal to be reproduced by the parametric speaker 140 into a modulation signal for the parametric speaker. At this time, the frequency of the carrier wave of the modulation signal is set to the frequency set by the frequency setting unit 120.

  The frequency setting unit 120 may directly input the audio quality required for the audio signal from the user, or may determine the audio quality based on attribute information of the audio signal to be reproduced. The attribute information here is, for example, the genre (music, movie sound, meeting, etc.) to which the audio signal belongs.

  As described above, according to the present embodiment, the quality of the sound output from the parametric speaker 140 can be increased as necessary. Further, an increase in power consumption of the parametric speaker 140 can be suppressed.

(Second Embodiment)
FIG. 4 is a block diagram illustrating a configuration of the speaker device according to the second embodiment. This speaker device has the same configuration as that of the speaker device according to the first embodiment, except that the speaker device 110 is provided.

  The directivity of the sound output from the parametric speaker 140 is preferably changed depending on the number of people located around the electronic device. For example, when there is only a user of the electronic device around the electronic device, the directivity may not be so high. However, when there is a person other than the user around the electronic device, it is necessary to increase directivity so that the voice other than the user cannot hear.

  In the present embodiment, the number-of-people detection unit 110 detects the number of people located around an electronic device having a speaker device. The frequency setting unit 120 sets the frequency of the modulation signal when the required voice quality is low based on the number of people detected by the number of people detection unit 110. Specifically, the frequency setting unit 120 sets the frequency higher when the number of people detected by the number of people detection unit 110 is more than that when the number of people detected is one. This is because, as described above, the directivity of the sound output from the parametric speaker 140 increases as the frequency of the modulation signal increases. The directivity of the sound output from the parametric speaker 140 increases as the frequency of the modulation signal increases. Therefore, according to this embodiment, the above-described needs can be satisfied.

  FIG. 5 is a diagram illustrating a first example of the configuration of the number-of-people detection unit 110. In this example, the number detection unit 110 includes an imaging unit 112 and an image processing unit 114. The imaging unit 112 is a camera attached to an electronic device, for example, and generates image data by imaging the periphery of the electronic device. The image processing unit 114 detects the number of people located around the electronic device by processing the image data generated by the imaging unit 112.

  FIG. 6 is a diagram illustrating a second example of the configuration of the number-of-people detection unit 110. In this example, the number detection unit 110 includes a sound acquisition unit 116 and a sound processing unit 118. The sound acquisition unit 116 is, for example, a microphone attached to the electronic device, and converts sound around the electronic device into sound data. The audio processing unit 118 processes the audio data generated by the audio acquisition unit 116 and recognizes the number of sound sources determined to be a person, thereby detecting the number of people located around the electronic device. Since the parametric speaker 140 is used, the region where the audible sound is demodulated can be separated from the microphone. In this case, an acoustic echo canceller is not required because an acoustic echo is hardly generated.

  Note that the number-of-people detection unit 110 preferably includes two microphones that are separated from each other. If it does in this way, the number detection part 110 can also identify a sound source using BSS (Blind Source separation) technique, and can recognize that this sound source is a person who should output an audio | voice. Thereby, the position of the user of the electronic device incorporating the speaker device can be detected in real time without using equipment such as a headset.

  Further, the number detection unit 110 may use the method shown in FIG. 5 and the method shown in FIG.

  Also according to this embodiment, the same effect as that of the first embodiment can be obtained. Further, the frequency setting unit 120 sets the frequency of the modulation signal based on the number of people detected by the number of people detection unit 110. Therefore, if the required voice quality is low, if there is only a user of the electronic device around the electronic device, the directivity is lowered, and if there are people other than the user around the electronic device, the directivity is reduced. Can be high.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

110 Number of people detection unit 112 Image pickup unit 114 Image processing unit 116 Audio acquisition unit 118 Audio processing unit 120 Frequency setting unit 130 Modulation unit 140 Parametric speaker

Claims (8)

A plurality of parametric speakers to which a modulation signal obtained by modulating an audio signal into an ultrasonic band is input;
Based on the audio quality required for the audio signal, it is determined whether or not the frequency of the modulation signal is different between the plurality of parametric speakers, and based on the determination result, the frequency in each of the plurality of parametric speakers is determined. A frequency setting means for setting the frequency of the modulation signal;
Modulation means for generating the modulation signal of the set frequency;
With
The frequency setting means includes
When the voice quality is high, the frequency of the modulation signal is made different among the plurality of parametric speakers,
A speaker device in which when the voice quality is low, the frequency of the modulation signal is matched between the plurality of parametric speakers, and lower than the highest frequency among the frequencies when the voice quality is high. The speaker device according to claim 1,
The parametric speaker has vibration means for outputting sound waves,
The frequency setting means selects a frequency that is an integral multiple of the resonance frequency of the vibration means as at least one of the frequencies, and the basic resonance of the vibration means as the frequency of the modulation signal when the audio quality is low A speaker device for setting a frequency. The speaker device according to claim 1,
The parametric speaker has vibration means for outputting sound waves,
Furthermore, it has a number of people detection means for detecting the number of people located around,
The frequency setting means selects a frequency that is an integral multiple of the resonance frequency of the vibration means as the frequency, and, when the voice quality is low, based on the number of people detected by the number of people detection means, the modulation signal Speaker device for setting the frequency of the. The speaker device according to claim 3, wherein
The frequency setting means is a speaker device that sets the frequency higher when the number of persons is more than that when the number of persons is one.   5. The speaker device according to claim 3, wherein the number-of-persons detection unit includes an imaging unit and an image processing unit that analyzes the image generated by the imaging unit and detects the number of people. The speaker device according to claim 3 or 4,
The speaker device includes a voice detection unit, and a voice processing unit that analyzes voice data generated by the voice detection unit and detects the number of people. In the speaker device according to any one of claims 1 to 6,
The said frequency setting means is a speaker apparatus which judges the said audio | voice quality based on the attribute of the said audio | voice signal.   The electronic device which has a speaker apparatus as described in any one of Claims 1-7.

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