JP5371688B2 - Car interior music playback system and music playback adapter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide "a music reproduction system for a vehicle interior and a music reproduction adapter" which can reproduce a music source with high quality from low-pitched sound to high-pitched sound when reproducing the music source, to which an in-dash audio system is not applicable, inside a vehicle. <P>SOLUTION: A sound signal reproduced by a portable music reproduction apparatus 10 is distributed into two systems by a music reproduction adapter 20. One sound signal is output to an on-dash speaker 30 and the other sound signal is processed by a low-pass filter 24, then FM-modulated by a transmitter section 26, transmitted to an in-dash audio device 40 and output to an in-dash speaker 50. Thus, music can be reproduced, after reducing a high-frequency component that may be easily affected by noise through the low-pass filter 24, with high quality from low-pitched sound output from the in-dash speaker 50 to middle/high-pitched sound output from the on-dash speaker 30. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a vehicle interior music playback system and a music playback adapter, and more particularly, to a system for a user to bring a portable music playback device that is not installed in a vehicle and play it.

  Most automobiles are equipped with genuine or commercially available in-vehicle audio devices. Many in-vehicle audio apparatuses support various music sources such as CD, DVD, MD, etc., and a user can play and enjoy a favorite music source in the passenger compartment. Usually, this type of in-vehicle audio device is stored in an empty space of the console, and the speaker is embedded in the lower part of the front door. Generally, a music playback system constructed with this type of in-vehicle audio device, speaker, or the like is called an in-dash type. Hereinafter, the in-dash type in-vehicle audio device is referred to as an in-dash type audio device, the speaker is referred to as an in-dash type speaker, and these are collectively referred to as an in-dash system.

  Recently, a mechanism for playing music sources that are not supported by in-dash audio devices in the passenger compartment is also provided. For example, an FM transmitter is connected to a portable music player brought from outside the vehicle compartment, and music data reproduced by the portable music player is wirelessly transmitted from the FM transmitter, which is transmitted to the FM of the in-dash audio device. There is a system that can receive a radio signal and output it from an in-dash speaker (see, for example, Patent Document 1).

  As another mechanism for playing music sources that are not supported by in-dash audio devices in the vehicle interior, a music playback system that supports music sources that are not supported by the in-dash audio device is provided in the vehicle interior. There is also a method of building independently.

  This type of music reproduction system includes an in-vehicle audio device that reproduces a music source that is not supported by the in-dash audio device, and a speaker that outputs music reproduced by the in-vehicle audio device. Speakers are generally placed on a dashboard because of the need to build a new system separately in a limited space in the passenger compartment. Therefore, an independent music playback system constructed separately from the in-dash music playback system is generally called an on-dash type. Hereinafter, the on-dash type in-vehicle audio device is referred to as an on-dash type audio device, the speaker is referred to as an on-dash type speaker, and these are collectively referred to as an on-dash system.

JP 2006-217582 A

  However, the former method using an FM transmitter to reproduce a music source that is not supported by the in-dash audio device in the passenger compartment has a problem in that high-frequency sounds cannot be reproduced well. That is, in FM radio, the upper limit of the reproduction frequency (frequency that can be handled by a speaker, an amplifier, etc.) is about 15 kHz according to regulations. Therefore, when an FM transmitter is used, there is a problem that an audible sound range having a frequency of 15 kHz or more (sound range of 15 kHz to 20 kHz) is cut and cannot be output from the speaker.

  Also, in the method using an FM transmitter, music data is modulated into high-frequency FM radio waves and transmitted wirelessly. Therefore, the higher the frequency, the more susceptible to high-frequency noise (radio noise), which adversely affects the quality of music playback. There was also a problem of giving.

  On the other hand, in the latter method that uses an on-dash system to reproduce music sources that are not supported by the in-dash audio device in the passenger compartment, it is necessary to construct a system separately from the in-dash system. At that time, since the on-dash type speaker needs to be placed in a limited space on the dashboard, a speaker having a large diameter cannot be used. For this reason, there is a limit to the reproduction capability of bass, and there is a problem that bass cannot be reproduced well compared to the in-dash system.

  The present invention has been made in order to solve such a problem, and when a music source that is not supported by the in-dash audio device is reproduced in the passenger compartment, it can be reproduced with high quality from low to high. The purpose is to.

In order to solve the above problems, in the present invention, the audio signal reproduced by the portable music player is distributed into two systems, and one of the distributed audio signals is output to the on-dash type first speaker. Further, the other distributed audio signal is processed by a low-pass filter and then modulated by a transmitter unit, and the modulated audio signal is transmitted as an electric wave to an in-dash audio device, and the audio signal is transmitted from the in-dash audio device to an in-dash type second signal. Output to the speaker. Here, the cutoff frequency of the low-pass filter is set in accordance with the lower limit of the frequency that can be output by the first speaker.

  According to the present invention configured as described above, middle and high frequency sound is mainly output from the first speaker whose diameter cannot be increased because of the on-dash type, and low frequency sound generated by the low-pass filter is transmitted from the transmitter unit. It is transmitted to the in-dash audio device and output from the in-dash second speaker whose diameter can be increased. Accordingly, high frequency noise generated by modulating the audio signal in the transmitter unit is reduced, and the low frequency sound output from the second speaker to the high frequency sound output from the first speaker. Quality music playback can be realized.

It is a block diagram which shows the function structural example of the vehicle interior music reproduction system by this embodiment. It is a figure which shows the example of installation in the vehicle interior of the vehicle interior music reproduction system by this embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of a functional configuration of a vehicle interior music playback system according to the present embodiment. FIG. 2 is a diagram showing an installation example in the vehicle interior of the vehicle interior music reproduction system according to the present embodiment.

  As shown in FIG. 1, the vehicle interior music playback system of this embodiment includes a portable music playback device 10 that is an example of an on-dash audio device, a music playback adapter 20, and an on-dash speaker 30 (the first embodiment of the present invention). 1), an in-dash audio device 40, and an in-dash speaker 50 (corresponding to the second speaker of the present invention).

  As shown in FIG. 2, the in-dash audio device 40 is accommodated in a free space of the console in front of the center of the front seat. The in-dash type speaker 50 is embedded and installed in the lower part of the front door, for example. The in-dash speaker 50 can be a large speaker having a diameter of, for example, about 16 cm, and is advantageous for reproduction in a low sound range.

  The music playback adapter 20 is connected to a cigar socket 60 and is configured to secure an operating power supply from a battery (not shown) through the cigar socket 60. The portable music playback device 10 is arbitrarily brought from outside the passenger compartment, and the music playback adapter 20 is configured to be connectable to the portable music playback device 10. The on-dash type speaker 30 is placed in an empty space on the dashboard. Since the empty space on the dashboard is limited, the on-dash speaker 30 is a small speaker having a diameter of about 8 cm, for example.

  The music playback adapter 20 distributes and processes the audio signal reproduced by the portable music playback device 10 between the first processing system and the second processing system, and has a functional configuration as shown in FIG. I have. As shown in FIG. 1, the music playback adapter 20 of this embodiment includes a volume 21, a distributor 22, a first amplifier 23, a low-pass filter 24, a second amplifier 25, a transmitter unit 26, and a transmission antenna 27. ing.

  The volume 21 adjusts the volume of the audio signal reproduced by the portable music player 10 in response to a user operation on an operation unit (not shown). The distributor 22 distributes the audio signal reproduced by the portable music player 10 into two systems. The first amplifier 23 amplifies one audio signal distributed by the distributor 22 and output to the on-dash speaker 30. The on-dash speaker 30 outputs sound based on the sound signal processed by the first amplifier 23 (first processing system) of the music playback adapter 20.

  The low-pass filter 24 cuts a high-frequency component that is easily affected by noise by reducing the high-frequency region of the other audio signal distributed by the distributor 22. When the audio signal is FM-modulated by the transmitter unit 26, the upper limit of the reproduction frequency is about 15 kHz according to FM radio regulations, so that the cutoff frequency of the low-pass filter 24 can be set to 15 kHz according to this upper limit. . The cut-off frequency of the low-pass filter 24 may be 15 kHz or less in accordance with the lower limit of the frequency that can be output by the on-dash type speaker 30. For example, the cut-off frequency can be about 200 Hz.

  The second amplifier 25 (corresponding to the amplifier of the present invention) amplifies the audio signal whose high frequency is cut by the low-pass filter 24. By amplifying only the low frequency component of the audio signal in this way, even if high frequency noise occurs in the processing of the transmitter unit 26 in the subsequent stage, the level of the high frequency noise is relative to that of the amplified low frequency audio signal. Can be made smaller.

  The transmitter unit 26 modulates the audio signal amplified by the second amplifier 25 and transmits it as a radio wave from the transmission antenna 27 to the in-dash audio device 40.

  The in-dash audio device 40 receives an audio signal processed by the second processing system (the low-pass filter 24, the second amplifier 25, and the transmitter unit 26) of the music playback adapter 20 as a radio wave, and processes the received radio wave. To output an audio signal. In order to perform this process, the in-dash audio device 40 includes a reception antenna 41 and a radio reception unit 42.

  The radio reception unit 42 receives the radio wave transmitted from the transmitter unit 26 of the music playback adapter 20 by the reception antenna 41 and demodulates the reception signal that has been subjected to FM modulation. The in-dash speaker 50 outputs sound based on the sound signal demodulated by the radio receiving unit 42.

  As described above in detail, in the present embodiment, the audio signal reproduced by the portable music player 10 is distributed to the two systems by the music playback adapter 20, and one audio signal is output to the on-dash speaker 30. Further, the other audio signal is processed by the low-pass filter 24 and then FM-modulated by the transmitter unit 26, transmitted to the in-dash type audio device 40 and output to the in-dash type speaker 50.

  According to the present embodiment configured as described above, middle and high frequency sounds are mainly output from the on-dash type speaker 30 having a diameter as small as about 8 cm. Further, a low-frequency sound obtained by cutting a high-frequency component that is susceptible to noise when the sound signal is FM-modulated by the low-pass filter 24 is transmitted from the transmitter unit 26 to the in-dash audio device 40, and the diameter is 16 cm. It is output from the in-dash type speaker 50 which is large. As a result, high-frequency noise generated by FM modulation of the audio signal can be reduced, and high-quality music reproduction from low-frequency sound to high-frequency sound can be realized.

  In the present embodiment, only the low frequency component of the audio signal generated by the low pass filter 24 is amplified by the second amplifier 25. As a result, even if high-frequency noise is generated by FM modulation of the transmitter unit 26, the level of the high-frequency noise can be made relatively smaller than the amplified low-frequency audio signal. Therefore, it is possible to prevent the high frequency noise from being noticed when the sound transmitted from the transmitter unit 26 to the in-dash type audio device 40 and output from the in-dash type speaker 50 is heard at a normal volume.

  In the present embodiment, the in-dash type speaker 50 is installed at the lower part of the front door, while the on-dash type speaker 30 is installed on the dashboard. Therefore, the on-dash type speaker 30 installed on the dashboard is closer to the passenger's ear than the in-dash type speaker 50. As a result, even if a small amount of high frequency noise is included in the sound output from the in-dash type speaker 50, it is masked by the middle and high range sound output from the on-dash type speaker 30 located closer to the ear. Is almost inaudible.

  In the above embodiment, the example in which the transmitter unit 26 performs FM modulation on the audio signal has been described. However, the present invention is not limited to this. For example, the audio signal may be digitally modulated.

  Strictly speaking, in the above-described embodiment, the low frequency sound output from the in-dash type speaker 50 is delayed as compared with the middle and high frequency sound output from the on-dash type speaker 30. However, since the sound causing the delay is only the bass part, the delay is not so much that the passenger can feel and take it. In order to accurately synchronize the mid-high frequency sound output from the on-dash type speaker 30 and the low-frequency sound output from the in-dash type speaker 50 (particularly when digital modulation is performed by the transmitter unit 26), Delay means may be provided in the first processing system.

  Moreover, although the said embodiment demonstrated the example which connects the adapter 20 for music reproduction to the cigar socket 60, and ensure a power supply, this invention is not limited to this. For example, when the in-dash audio device 40 is stored and there is still an empty space in the console, the music playback adapter 20 may be stored in the console and the power supply may be secured by wiring on the back side.

  In the above-described embodiment, the example in which the volume 21 is provided before the distributor 22 has been described. However, the volume 21 may be provided between the distributor 22 and the first amplifier 23. In this case, the volume 21 is a means for adjusting the volume of only the sound output from the on-dash speaker 30. Then, by adjusting the volume of the mid-high range sound output from the on-dash type speaker 30 with the volume 21, the high-frequency noise masking effect by the mid-high range sound can be further strengthened. Note that the volume of the sound output from the in-dash type speaker 50 is, for example, a volume adjustment operation unit provided in the portable music playback device 10 or a volume adjustment operation provided in the in-dash type audio device 40. It is possible to adjust by part.

  In addition, each of the above-described embodiments is merely an example of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. In other words, the present invention can be implemented in various forms without departing from the spirit or main features thereof.

DESCRIPTION OF SYMBOLS 10 Portable music reproduction apparatus 20 Adapter for music reproduction 22 Distributor 23 1st amplifier 24 Low pass filter 25 2nd amplifier 26 Transmitter part 30 On-dash type speaker 40 In-dash type audio apparatus 42 Radio receiving part 50 In-dash type speaker

Claims (5)

A vehicle interior music reproduction system for reproducing music in a vehicle interior,
A music playback adapter configured to be connectable to a portable music player, and distributing an audio signal reproduced from the portable music player to the first processing system and the second processing system;
A first speaker that outputs sound based on an audio signal processed by the first processing system of the music playback adapter;
An in-dash audio device that receives the audio signal processed by the second processing system of the music playback adapter as a radio wave, processes the received radio wave, and outputs the audio signal;
A second speaker for outputting sound based on the sound signal processed by the in-dash audio device,
The music playback adapter includes, as the second processing system, a low-pass filter that reduces a high frequency range of an audio signal played from the portable music playback device;
A transmitter unit that modulates the audio signal processed by the low-pass filter and transmits it as the radio wave,
The in-dash audio device includes a radio receiving unit that receives and demodulates radio waves transmitted from the transmitter unit ,
A vehicle interior music reproduction system , wherein a cutoff frequency of the low-pass filter is set in accordance with a lower limit of a frequency that can be output by the first speaker . The in-vehicle music according to claim 1, wherein the music playback adapter further includes an amplifier that amplifies an audio signal processed by the low-pass filter between the low-pass filter and the transmitter unit. Playback system. The vehicle interior music reproduction system according to claim 1 or 2, wherein the first speaker is placed on a dashboard in the vehicle interior. A distributor for distributing an audio signal reproduced by the portable music player;
A first amplifier that amplifies one of the audio signals distributed by the distributor and output to an on-dash first speaker;
A low pass filter for reducing the high frequency range of the other audio signal distributed by the distributor;
A transmitter unit that modulates the audio signal processed by the low-pass filter and transmits it as an electric wave to the in-dash audio device ;
A music playback adapter , wherein the cut-off frequency of the low-pass filter is set in accordance with a lower limit of a frequency that can be output by the first speaker . 5. The music playback adapter according to claim 4, further comprising an amplifier that amplifies an audio signal processed by the low-pass filter between the low-pass filter and the transmitter unit.