JP2011010183A - Music reproduction system, mobile terminal device and music reproduction program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce a piece of music with high sound quality while enhancing output characteristics of speakers by reproducing one piece of music data using a plurality of devices whose low-range output characteristics are not sufficient.SOLUTION: In a music reproduction system, each of a plurality of mobile terminal devices performs reproduction processing on the basis of at least one piece of individual music data constituting one piece of music data, so that a plurality of music reproduction apparatuses reproduce pieces of music on the basis of one piece of music data. Each of the plurality of music reproduction apparatuses comprises: a speaker for outputting acoustics; a memory for storing individual music data reproduced by a player in at least one piece of individual music data constituting the music data; a data converting means for attenuating the individual music data stored in the memory on the basis of the output characteristic of the speaker; and a reproduction means for reproducing the individual music data which are attenuated by the data converting means while synchronizing reproduction timing with the other music reproduction apparatus and outputting the individual music data from the speaker.

Description

  The present invention is a technique for playing back music based on music data, and particularly uses a plurality of mobile terminal devices such as mobile phones, PDAs (Personal Digital Assistants), and mobile game machines equipped with small speakers. The present invention relates to a music reproduction technique for reproducing one music with high sound quality.

  2. Description of the Related Art In recent years, performance improvements relating to video have been remarkable in portable terminal devices, and it has become possible to enjoy high-quality video even with a small screen size as the display becomes higher in definition. On the other hand, performance related to sound has not been improved so much, for example, it is difficult to enjoy music with good sound quality even when music is played on a mobile terminal device. This is because the speaker mounted on the portable terminal device is a small speaker, and therefore the output characteristics in the low sound range are low.

  By the way, conventionally, as one technique for reproducing surround sound using a plurality of portable terminal devices, for example, it has been proposed to divide acoustic data and reproduce it on a plurality of portable terminal devices cooperating appropriately (for example, patents). Reference 1).

JP 2003-47098 A

  However, the above-mentioned Patent Document 1 does not particularly mention improvement of output characteristics in a low frequency range that is peculiar to a portable terminal device having a small speaker. For this reason, the output characteristics in the low sound range are deteriorated in each of the plurality of portable terminal devices, and as a result, a problem that a sufficient low sound output cannot be obtained still remains.

  Therefore, the present invention has been made for the purpose of solving the conventional problems, and by reproducing a piece of music data using a plurality of devices equipped with speakers having insufficient output characteristics in the low range, The present invention provides a music playback system, a mobile terminal device, and a music playback program that can perform music playback with high sound quality with improved output characteristics of individual speakers.

  In order to achieve the above object, the first configuration according to the present invention is configured such that each of a plurality of music playback devices performs a playback process based on at least one individual music data constituting one music data. A music playback system that plays back music based on a single piece of music data by a music playback device, wherein each of the plurality of music playback devices includes a speaker that outputs sound and at least one individual music data that constitutes one piece of music data. Among them, storage means for storing individual music data to be reproduced in the apparatus, data conversion means for attenuating the individual music data stored in the storage means based on the output characteristics of the speaker, and other music reproduction apparatuses Reproduction means for reproducing individual music data attenuated by the data conversion means and outputting from the speaker in synchronization with the reproduction timing It is configured to include.

  In this case, it is preferable that the data conversion means attenuates the individual musical piece data by an inverse characteristic filter of the frequency characteristic of the speaker. Each of the plurality of music playback devices further includes communication means for performing data communication with other music playback devices, and one of the plurality of music playback devices is individual music data to be played back by each music playback device. Is preferably generated from the music data, and the individual music data is transmitted to the other music playback device via the communication means, and the playback timing is instructed to the other music playback device.

  Further, when the music data is surround data including low frequency data and one or more channel data, each of the plurality of music playback devices reproduces based on the channel data and low frequency data assigned to each device. You may comprise so that it may perform. Further, when the music data is surround data including low-frequency data and one or more channel data, each of the plurality of music playback devices has high-frequency data extracted from channel data assigned to each device, You may comprise so that reproduction | regeneration may be performed based on the data which added the low frequency data extracted from all the channel data to the data for low frequency.

  According to a second configuration of the present invention, there is provided a portable terminal device, and an individual musical piece to be reproduced in the device among a speaker for outputting sound and at least one individual musical piece data constituting one musical piece data. The storage means for storing data, the data conversion means for attenuating the individual music data stored in the storage means based on the output characteristics of the speaker, and the synchronization of the reproduction timing by performing data communication with other portable terminal devices Communication means, and individual music data attenuated by the data conversion means are reproduced at a reproduction timing and output from a speaker. Even in this case, it is preferable that the data conversion means attenuates the individual musical piece data by the inverse characteristic filter of the frequency characteristic of the speaker.

  The music data is stored in the storage means of the mobile terminal device, and the number of music data to be played back is determined by performing data communication with other mobile terminal devices via the communication means, and played back on each mobile terminal device. The target individual music data may be generated from the music data and transmitted to another mobile terminal device, and the playback timing may be instructed to the other music playback device.

  When the music data is surround data including low frequency data and one or more channel data, low frequency data and at least one channel data are allocated to each portable terminal device based on the number of music data to be reproduced. The data assigned to each mobile terminal device may be transmitted via the communication means. Further, when the music data is surround data including low frequency data and one or more channel data, the high frequency data and low frequency data of each channel data are separated to obtain low frequency data obtained from all channel data. Based on the number of music data that is added to the low frequency data and assigned to each portable terminal device, low frequency data added with the low frequency data and high frequency data separated from at least one channel data are allocated to each portable terminal device The data assigned to each mobile terminal device may be transmitted via the communication means.

  According to a third aspect of the present invention, there is provided a music reproduction program executed by a mobile terminal device provided with a speaker. At least one individual music data constituting one piece of music data is stored in the mobile terminal device. A step of storing in the storage means, a step of attenuating the individual music data stored in the storage means based on the output characteristics of the speakers, and a step of synchronizing the reproduction timing by performing data communication with other portable terminal devices; The attenuated individual music data is reproduced at the reproduction timing and output from the speaker.

  According to the present invention, even when a single piece of music data is played back using a plurality of devices including speakers whose output characteristics in the low frequency range are not sufficient, individual music data to be played back in each device is stored in the speaker. Attenuation is performed based on the output characteristics, and reproduction is performed in synchronization with other devices on the basis of the attenuated individual music data, so that high-quality music reproduction having a substantially flat frequency characteristic can be performed. Also, since each device performs synchronized playback, the output level as a song can be improved. Furthermore, even if the music data is surround data, it is possible to improve the playback sound quality by playing back the bass data on all devices.

It is a figure which shows the structural example of the music reproduction system in 1st Embodiment. It is a block diagram which shows the example of 1 structure of each portable terminal device. It is a figure which shows a frequency characteristic. It is a figure which shows a frequency characteristic. It is a figure which shows a frequency characteristic. It is a flowchart which shows an example of the process sequence in 1st Embodiment. It is a figure which shows the structural example of the music reproduction system in 2nd Embodiment. It is a figure which shows a frequency characteristic. It is a figure which shows a frequency characteristic. It is a flowchart which shows an example of the process sequence in 2nd Embodiment. It is a flowchart which shows an example of the process sequence in 2nd Embodiment. It is a figure which shows a frequency characteristic. It is a figure which shows a frequency characteristic. It is a block diagram which shows the function structure in 3rd Embodiment. It is a flowchart which shows an example of the process sequence in 3rd Embodiment. It is a flowchart which shows an example of the process sequence in 3rd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each embodiment demonstrated below, the same code | symbol is attached | subjected to the member which is mutually common, and the overlapping description about them is abbreviate | omitted.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of a music playback system 1 according to the first embodiment. The music playback system 1 includes a plurality of portable terminal devices 2 as music playback devices. In the example shown in the figure, the music playback system 1 is configured by five mobile terminal devices 2, but the number of mobile terminal devices 2 is not limited to this. Each mobile terminal device 2 is a device such as a mobile phone, a PDA (Personal Digital Assistants), or a mobile game machine, and includes a small speaker 15 for performing sound output (see FIG. 2). In the music playback system 1, each of the plurality of mobile terminal devices 2 performs playback processing synchronized with each other based on one music data, thereby improving the output characteristics of the speakers and playing back high-quality music. Composed. Here, one of the plurality of portable terminal devices 2 functions as the master device 3, and the other devices function as the slave device 4. The master device 3 synchronizes at the time of music reproduction by instructing the reproduction timing to the slave device 4, for example.

  FIG. 2 is a block diagram illustrating a configuration example of each mobile terminal device 2. The illustrated example shows a case where the mobile terminal device 2 is a mobile phone, and includes an antenna 11 and a radio wave transmission / reception unit 12 that transmits / receives radio waves to / from a communication base station via the antenna 11. In addition, the mobile terminal device 2 outputs a sound signal to the microphone 13 that inputs sound, a sound input unit 14 that processes a sound signal from the microphone 13, a small-sized speaker 15 that performs sound output, and the speaker 15. A speaker output unit 16, a wireless communication unit 17 for performing wireless communication with another mobile terminal device 2, an external interface 18 for connecting a cable to another mobile terminal device 2, or mounting a memory card, etc. A CPU 19 for executing a program, a memory 20 for storing various data, a display unit 21 such as a liquid crystal display, an operation unit 22 and a clock circuit 23 as an internal clock for counting the current time are provided. These units are configured to be able to perform data input / output with each other via the data bus 24.

  The CPU 19 implements various functions in each portable terminal device 2 by executing a predetermined program as the power is turned on. In particular, in the present embodiment, a music playback program 8 for playing back one piece of music in synchronization with a plurality of mobile terminal devices 2 is stored in advance in the memory 20 of each mobile terminal device 2, and the CPU 19 stores the music playback program. 8 is executed. The music reproduction program 8 is acquired by the radio wave transmission / reception unit 12 being downloaded from a predetermined download site via a communication base station, for example, and stored in the memory 20. Further, it may be acquired from another portable terminal device 2 or a memory card via the wireless communication unit 17 or the external interface 18 and stored in the memory 20. In each of the plurality of portable terminal devices 2, the CPU 19 executes the music reproduction program 8, whereby the plurality of portable terminal devices 2 perform data communication with each other, one of which is determined as the master device 3, and the other Is determined as the slave device 4. The master device 3 may be determined by manual operation when the music playback program 8 is started.

  The memory 20 stores music data 9 to be played back in each mobile terminal device 2. The music data 9 may be individually acquired by each mobile terminal device 2, but in this embodiment, the master device 3 transmits the music data to the other slave devices 4, and each slave device 4 is the master device. The music data received from 3 is stored in the memory 20. For example, all the music data 9 constituting one music is stored in advance in the memory 20 of the master device 3, and the master device 3 uses the music data 9 to play the music to be individually reproduced in each slave device 4. Data is extracted (hereinafter also referred to as “individual music data”) and transmitted. Here, data communication between the master device 3 and the slave device 4 is performed via the wireless communication unit 17 or a cable connected to the external interface 18. Note that the communication form by the wireless communication unit 17 may be infrared communication such as IRDA (Infrared Data Association) or radio wave communication not via a base station such as Bluetooth.

  Each of the plurality of portable terminal devices 2 reproduces the music data 9 (individual music data) stored in the memory 20 at a reproduction timing instructed by the master device 3. At this time, each mobile terminal device 2 converts and reproduces the individual music data so that the frequency characteristics of the sound output from the respective speakers 15 have substantially flat frequency characteristics, thereby reproducing a plurality of mobile terminal devices 2. So that the music output from can be played with high sound quality.

  Hereinafter, the case where the music data 9 is monaural data or stereo data will be exemplified, and the details of processing at the time of music reproduction in each mobile terminal device 2 will be described. FIGS. 3 to 5 are diagrams showing frequency characteristics in which the vertical axis represents the sound pressure level (SPL) and the horizontal axis represents the frequency (Hz). First, FIG. 3A shows the frequency characteristics of the speaker 15 provided in each portable terminal device 2. Since the speaker 15 of each portable terminal device 2 is a small speaker, the output characteristics on the low frequency side deteriorate. In the example shown in the figure, the output characteristics are degraded at a frequency of 1 kHz or less. When music data having a substantially flat frequency characteristic is reproduced with such a speaker 15 as shown in FIG. 3A, good sound quality can be obtained in a high sound range exceeding a predetermined frequency (1 kHz). In the low frequency range of 1 kHz or less, the output is reduced, and good sound quality cannot be obtained, and the frequency characteristic of the sound reproduced from the speaker 15 is as shown in FIG.

  Therefore, each mobile terminal device 2 attenuates the frequency characteristic of the music data to be reproduced based on the output characteristic of the speaker 15 in order to make the frequency characteristic of the sound output from each speaker 15 substantially flat. Specifically, as shown in FIG. 4A, the music data is converted using a filter having a reverse characteristic to the frequency characteristic of the speaker 15. FIG. 4B shows frequency characteristics after music data is converted using the inverse characteristic filter of the speaker 15.

  When each mobile terminal device 2 reproduces music based on music data that has been converted using an inverse characteristic filter, the frequency characteristics of the sound output from the speaker 15 are as shown in FIG. It becomes a characteristic. That is, the frequency characteristic of the sound output from each mobile terminal device 2 is a substantially flat frequency characteristic. However, in this case, a single mobile terminal device 2 cannot output a sufficient sound pressure level. Therefore, as shown in FIG. 5B, the sound pressure level as a whole is increased by synchronizing a plurality of portable terminal devices 2 to reproduce one piece of music.

  Here, the maximum output level at which a single portable terminal device 2 can reproduce music with a substantially flat frequency characteristic is the maximum output that the speaker 15 of the portable terminal device 2 can output at the lowest frequency (for example, 100 Hz). Depends on the level. If the maximum output level at the minimum frequency is XdB (SPL), for example, when one piece of music is played back synchronously with four mobile terminal devices 2, the maximum output level of the sound pressure level as a whole increases by about 12 dB. (X + 12) db (SPL) is the maximum output level of the entire system. When one music piece is reproduced synchronously with the eight mobile terminal apparatuses 2, the maximum output level of the sound pressure level as a whole increases by about 18 dB, and (X + 18) db (SPL) is the maximum output of the entire system. Become a level. Therefore, the maximum output level of the entire system increases as the number of portable terminal devices 2 constituting the music reproduction system 1 is increased. As a result, each speaker 15 provided in each mobile terminal device 2 improves the frequency characteristics of the music played back as a whole system to a high sound quality with a substantially flat characteristic even though the output characteristics in the low sound range are low. Can be reproduced with a sufficient sound pressure level.

  The above increase value of the maximum output level is an ideal case, and the phase of the sound from each portable terminal device 2 is shifted depending on the position of each portable terminal device 2 and the position of the listener (user). The maximum output level of the entire system is lower than the above value. However, the main focus here is on improving the low-frequency region. Since the low-frequency component has a long wavelength and is easily phase-synthesized, the maximum output level close to the above-mentioned value can be expected for the low-frequency region. It becomes like this.

  Next, each operation | movement of the master apparatus 3 and the slave apparatus 4 in this embodiment is demonstrated. FIG. 6 is a flowchart illustrating an example of a processing procedure in the master device 3 and the slave device 4. Although only one slave device 4 is shown in the figure, the processing procedure in these slave devices 4 is the same even when there are two or more slave devices 4.

  First, the music playback program 8 is activated in each of the master device 3 and the slave device 4. Thereby, each process shown in FIG. 6 is started. Here, it is assumed that each of the master device 3 and the slave device 4 is determined by a user input operation when the music playback program 8 is started. When the music playback program 8 is activated in each of the master device 3 and the slave device 4, each of the master device 3 and the slave device 4 starts data communication with each other (steps S100 and S200). Through this data communication, the master device 3 determines the number of portable terminal devices 2 that reproduce one piece of music (step S101). Then, the master device 3 transmits the clock data indicated by the clock circuit 23 of the master device 3 to the slave device 4 (step S102). The slave device 4 receives this clock data, and establishes the synchronization state of the internal clock by correcting the deviation between the current time of its own clock circuit 23 and the current time of the master device 3 (step S201). When the internal clock is synchronized, the slave device 4 waits to receive the music data (individual music data) to be reproduced by itself from the master device 3 (step S203).

  On the other hand, after transmitting the clock data, the master device 3 selects the music data 9 to be reproduced from at least one music data 9 stored in the memory 20 based on, for example, an input operation by the user (step S103). ). Then, the master device 3 extracts music data (individual music data) to be reproduced by each slave device 4 from the selected music data 9, and starts transmission to each slave device 4 (step S104). For example, in the case of stereo data, since the music data 9 includes data for two left and right channels, either one of the left and right channel data is extracted and transmitted to each slave device 4. In the case of monaural data, the entire music data 9 stored in the master device 3 is transmitted to each slave device 4.

  Accordingly, the slave device 4 starts receiving music data (individual music data) from the master device 3 (step S204). When the reception is completed (YES in step S205), the slave device 4 sends a reception completion notification to the master device 3 (step S206). Then, the slave device 4 performs data conversion on the music data (individual music data) received from the master device 3 (step S207). Here, data conversion is performed based on the inverse characteristic filter of the speaker 15 provided in the slave device 4. Various parameters relating to the inverse characteristic filter are set in advance for the music reproduction program 8 started by the slave device 4. When the slave device 4 completes the data conversion, a preparation completion notice is sent to the master device 3 (step S208). Then, the slave device 4 waits for a reproduction instruction from the master device 3 (step S209).

  When the master device 3 receives the reception completion notification from the slave device 4 (step S105), the master device 3 determines whether or not all the slave devices 4 have completed reception (step S106), and receives the reception completion notification from all the slave devices 4. Is received (NO in step S106). When reception completion notifications are received from all the slave devices 4 (YES in step S106), the master device 3 performs data conversion of music data (individual music data) to be reproduced by the own device (step S107). Here, data conversion is performed based on the inverse characteristic filter of the speaker 15 provided in the master device 3. In this case as well, various parameters relating to the inverse characteristic filter are set in advance for the music playback program 8 started by the master device 3. When the master device 3 finishes the data conversion, the master device 3 waits to receive a preparation completion notification from the slave device 4 (step S108). When the preparation completion notification is received from the slave device 4, it is determined whether or not all the slave devices 4 are ready (step S109), and waits until all the slave devices 4 are ready (step S109). NO in S109).

  When all the slave devices 4 are ready, the master device 3 transmits a reproduction timing to each slave device 4 (step S110). The reproduction timing is specified by, for example, determining the time to start reproduction on the internal clock of the master device 3. Each slave device 4 receives the reproduction timing from the master device 3 (step S210), thereby grasping the time to start reproduction. Then, when each of the master device 3 and the slave device 4 grasps that it is the reproduction timing (YES in step S111, YES in step S211), it is based on music data (individual music data) that has been converted in advance. Playback of the music is started (steps S112 and S212). At this time, since the internal clocks of the master device 3 and the slave device 4 are not shifted by the above-described processing, each of the master device 3 and the slave device 4 starts playing the music at the same time.

  As a result, in each of the master device 3 and the slave device 4, although the output level is low, high-quality music reproduction with a substantially flat characteristic in all frequency ranges is performed. Then, when each of the master device 3 and the slave device 4 starts music reproduction at the same time, the output level of the entire music increases, and a sufficient sound pressure level can be obtained. Therefore, the music reproducing system 1 of the present embodiment uses a plurality of portable terminal devices 2 including the speakers 15 whose output characteristics in the low frequency range are not sufficient to simultaneously reproduce one piece of music data, thereby High-quality music playback with improved output characteristics can be performed.

(Second Embodiment)
FIG. 7 is a diagram illustrating a configuration example of the music reproduction system 1a according to the second embodiment. In this embodiment, the music data 9 to be played back by the music playback system 1a is low-frequency data (woofer data), such as 3.1ch, 5.1ch, 7.1ch, or 9.1ch, and 1 The case where it is the surround data containing the above channel data is illustrated. The figure shows an arrangement example suitable for reproducing 5.1ch surround data, and the music reproduction system 1a includes a mobile terminal device 2a arranged at the front center position of the user who listens to the reproduction music, A mobile terminal device 2b arranged at the front side right position, a mobile terminal device 2c arranged at the front side left position, a mobile terminal device 2d arranged at the rear side right position, and a rear side left position. Mobile terminal device 2e. Among the plurality of portable terminal devices 2a, 2b, 2c, 2d, and 2e, the portable terminal device 2a functions as the master device 3, and the other portable terminal devices 2b, 2c, 2d, and 2e function as the slave device 4. Here, an example in which the music playback system is configured with five mobile terminal devices is shown, but the number of mobile terminal devices is not limited to this, and for example, a plurality of mobile terminal devices may be installed at each position. . In addition, the structure of each portable terminal device 2a-2e is the same as that of what was shown in FIG.

  FIG. 8 and FIG. 9 are diagrams showing frequency characteristics in which the vertical axis represents the sound pressure level (SPL) and the horizontal axis represents the frequency (Hz). First, as shown in FIG. 8A, the surround data includes woofer data and channel data corresponding to the position of each speaker 15. In the case of 5.1ch, there are five channel data.

  As shown in FIG. 8A, the woofer data is low-frequency data (low-frequency data), and therefore the data contains almost no high-frequency component. On the other hand, the frequency characteristics of each channel data are substantially flat characteristics. When such surround data is reproduced as it is in each of the mobile terminal devices 2a to 2e, the output of the low sound range is lowered due to the frequency characteristic (output characteristic) of the speaker 15. As a result, each of the woofer data and each channel data has a distorted characteristic different from the characteristic shown in FIG. 8A in the low sound range, so that the sound quality is deteriorated.

  Therefore, also in this embodiment, as in the first embodiment, each mobile terminal device 2a to 2e performs data conversion using an inverse characteristic filter corresponding to the output characteristics of the speaker 15, and the woofer data and each channel data Attenuate each of the. Then, each of the attenuated woofer data and each channel data is reproduced by each of the portable terminal devices 2a to 2e.

  Here, assuming that the attenuated woofer data and each channel data are reproduced by one mobile terminal device, the frequency characteristics of the reproduced woofer sound and the frequency characteristics of each channel sound are shown in FIG. ) As shown. As shown in FIG. 8B, the sound pressure level of the woofer sound and each channel sound is suppressed to be equal to or lower than the maximum output level at the lowest frequency of the speaker 15. Therefore, a sufficient sound pressure level cannot be obtained in this state.

  Therefore, in the present embodiment, the woofer data, which is low directivity data with low directivity, is reproduced by all the mobile terminal devices 2a to 2e, thereby increasing the sound pressure level of the woofer sound as a whole system. Further, each channel data including a high directivity high frequency range is individually reproduced by the mobile terminal devices 2a to 2e corresponding to the respective positions arranged around the user. At this time, in accordance with the sound pressure level of the woofer sound as a whole system, each channel data is amplified by an amplifier to increase the sound pressure level of each channel sound.

  FIG. 9 shows the frequency characteristic of each channel sound and the frequency characteristic of the woofer sound reproduced as described above. As shown in FIG. 9, since the woofer sound is reproduced by all of the plurality of mobile terminal devices 2a to 2e, the sound pressure level is increased compared to FIG. 8B. Since each channel sound is amplified and reproduced by one mobile terminal device, a sound pressure level substantially equal to the woofer sound can be obtained in the middle to high sound range. On the other hand, since the low frequency range portion L of each channel sound is affected by the output characteristics of the speaker 15, it may not be reproduced equivalent to the frequency characteristics of the original channel data. However, in this embodiment, since the woofer sound is output from all the mobile terminal devices 2 a to 2 e and a high sound pressure level is obtained, the low sound output included in each channel is suppressed by the output characteristics of the speaker 15. Even if it does, the effect is small. Therefore, the music reproduction system 1a of the present embodiment can reproduce the music data 9 as surround data with high sound quality by the plurality of portable terminal devices 2a to 2e.

  Next, each operation | movement of the master apparatus 3 and the slave apparatus 4 in this embodiment is demonstrated. FIG. 10 and FIG. 11 are flowcharts showing an example of processing procedures performed by the master device 3 and the slave device 4 in the present embodiment. Although only one slave device 4 is shown in the figure, the processing procedure of the other slave devices 4 is the same.

  First, the music playback program 8 is activated in each of the master device 3 and the slave device 4. Thereby, each of the master apparatus 3 and the slave apparatus 4 is determined, and each process is started. When the music playback program 8 is activated in each of the master device 3 and the slave device 4, each of the master device 3 and the slave device 4 starts data communication with each other (steps S130 and S230). Through this data communication, the master device 3 determines the number of the mobile terminal devices 2 that reproduce one piece of music (step S131). In addition, after data communication, the slave device 4 selects the installation position of the speaker 15 based on a user input operation (step S231), and transmits information related to the speaker installation position to the master device 3 (step S232). The master device 3 determines the positions of the plurality of speakers 15 based on the information regarding the speaker installation positions received from each slave device 4 (step S132). The installation position of the master device 3 is set as a default as the front center position.

  Then, the master device 3 assigns a channel to each slave device 4 based on the installation position of each slave device 4, and determines channel data to be reproduced by each slave device 4 (step S134). Thereafter, the master device 3 transmits the clock data indicated by the clock circuit 23 of the master device 3 to the slave device 4 (step S135). The slave device 4 receives this clock data, and corrects the difference between the current time of its own clock circuit 23 and the current time of the master device 3, thereby establishing the synchronization state of the internal clock with the master device 3 ( Step S233). When the internal clock is synchronized, the slave device 4 waits to receive individual music data (in the case of this embodiment, woofer data and channel data) from the master device 3 when it is synchronized with the internal clock. (Step S234).

  On the other hand, after transmitting the clock data, the master device 3 selects the music data 9 to be reproduced from at least one music data 9 stored in the memory 20 based on, for example, a user input operation (step S136). ). Then, the master device 3 calculates an output level (sound pressure level) when the woofer data included in the selected music data 9 is reproduced by all of the plurality of portable terminal devices 2a to 2e (step S137). Based on the output level, a gain to be given to each channel data is calculated (step S138). Then, the master device 3 extracts channel data and woofer data to be reproduced in each slave device 4 from the music data 9, and starts transmission to each of the slave devices 4 (step S139). As a result, the channel data corresponding to the installation position and the woofer data are sent to each slave device 4 as individual music data. At this time, the master device 3 transmits a gain to be given to the channel data to each slave device 4.

  The slave device 4 starts receiving individual music data including channel data and woofer data transmitted from the master device 3 (step S235). When the reception is completed, the channel data received from the master device 3 and the woofer data are converted (step S236). Here, processing for attenuating each of the channel data and the woofer data is performed based on the inverse characteristic filter of the speaker 15 provided in the slave device 4. When the data conversion is completed, next, a gain to be given to the channel data is set (step S237).

  On the other hand, when the master device 3 completes the data transmission to each slave device 4, the master device 3 performs data conversion between the master device channel data and the woofer data (step S140). Here, based on the inverse characteristic filter of the speaker 15 provided in the master device 3, processing for attenuating each of the channel data and the woofer data is performed. When the data conversion is completed, next, a gain to be given to the channel data is set (step S141).

  Proceeding to the flowchart of FIG. 11, when the slave device 4 finishes the above-described processing, the slave device 4 notifies the master device 3 of completion of preparation (step S238), and waits for a reproduction instruction from the master device 3 (step S238). S239). In addition, when the master device 3 receives the preparation completion notification from the slave device 4 (step S142), the master device 3 determines whether or not all the slave devices 4 are ready (step S143), and determines that all the slave devices 4 are ready. It waits until it becomes (NO in step S143).

  When all the slave devices 4 are ready, the master device 3 transmits a reproduction timing to each slave device 4 (step S144). Each slave device 4 receives the reproduction timing from the master device 3 (step S240), thereby grasping the time to start reproduction. When each of the master device 3 and the slave device 4 grasps that the playback timing has come (YES in step S145, YES in step S241), the individual music data (that is, the woofer data and the data converted beforehand) are converted. The reproduction of the music is started based on each channel data (steps S146 and S242). Thereby, each of the master apparatus 3 and the slave apparatus 4 starts reproduction | regeneration of a music simultaneously.

  As a result, the surround data is reproduced as the music reproducing system 1a. In particular, since the woofer sound is reproduced by all the mobile terminal devices 2a to 2e while maintaining good frequency characteristics, it is output at a high sound pressure level. Each channel sound is also output at a sound pressure level that matches the sound pressure level of the woofer sound by applying gain in each of the mobile terminal devices 2a to 2e. Accordingly, in the present embodiment, surround data can be reproduced with high sound quality by the plurality of portable terminal devices 2a to 2e.

(Third embodiment)
In the second embodiment described above, there is a possibility that the output of the low frequency range of each channel included in the surround data may be reduced due to the output characteristics of the speaker 15. In view of this, in the present embodiment, a description will be given of an embodiment in which the low sound range of each channel can be reproduced well. Note that the configuration of the music playback system in this embodiment is the same as that in the second embodiment.

  FIG. 12 and FIG. 13 are diagrams showing frequency characteristics in which the vertical axis represents the sound pressure level (SPL) and the horizontal axis represents the frequency (Hz). In this embodiment, as shown in FIG. 12A, each channel data included in the surround data is separated into low frequency data and high frequency data. For example, in the case of 5.1ch, since there are five channel data, all of the five channel data are separated into low frequency data and high frequency data. Then, as shown in FIG. 12B, all the low frequency data separated from each channel data is added to the woofer data included in the surround data to generate new woofer data.

  Also in this embodiment, as in each of the embodiments described above, the woofer data obtained by performing data conversion using the inverse characteristic filter corresponding to the output characteristics of the speaker 15 in each portable terminal device 2a to 2e and adding the low frequency data. Each of the high frequency data separated from the channel data is attenuated. Then, the attenuated woofer data and the high frequency data of each channel data are reproduced by each of the portable terminal devices 2a to 2e.

  Here, assuming that the attenuated woofer data and the high frequency data of each channel data are reproduced by one mobile terminal device, the frequency characteristics of the reproduced woofer sound and the frequency characteristics of each channel sound are as follows: As shown in FIG. As shown in FIG. 13A, since the sound pressure level of the woofer sound and each channel sound is suppressed to be equal to or lower than the maximum output level at the lowest frequency of the speaker 15, a sufficient sound pressure level cannot be obtained in this state.

  Therefore, in this embodiment as well, as in the second embodiment, woofer data (that is, woofer data obtained by adding the low frequency data of each channel), which is low directivity data for bass, is used for all portable terminals. Playback is performed by the devices 2a to 2e, thereby increasing the sound pressure level of the woofer sound as a whole system. In addition, the high frequency data separated from each channel data including high directivity with high directivity is individually reproduced by the mobile terminal devices 2a to 2e corresponding to the respective positions arranged around the user. At this time, in accordance with the sound pressure level of the woofer sound as a whole system, the high frequency data of each channel data is amplified by an amplifier to increase the sound pressure level of the high frequency sound of each channel.

  FIG. 13B shows the frequency characteristic of each channel sound and the frequency characteristic of the woofer sound reproduced as described above. As shown in FIG. 13B, since the woofer sound is reproduced by all of the plurality of mobile terminal devices 2a to 2e, the sound pressure level is increased as compared with FIG. 13A. And since the low frequency sound contained in each channel is added to this woofer sound, the low frequency sound of each channel is also reproduced well. Further, since the high frequency sound included in each channel is amplified and reproduced by one portable terminal device, a sound pressure level substantially equivalent to the woofer sound can be obtained. Therefore, in the present embodiment, the music data 9 that is surround data can be reproduced with higher sound quality without deteriorating the low frequency range included in each channel.

  FIG. 14 is a block diagram showing a functional configuration in each of the mobile terminal devices 2a to 2e, and shows a case where the music data 9 is 5.1ch surround data. The music data 9 corresponds to the channel data D1 corresponding to the front center position of the user, the channel data D2 corresponding to the front right position, the channel data D3 corresponding to the front left position, and the rear right position. Channel data D4, channel data D5 corresponding to the rear left side position, and woofer data D6.

  The master device 3 includes a high-pass filter (HPF) that extracts high-frequency data from the channel data D1 to D5 and a low-pass filter (LPF) that extracts low-frequency data. The two filters provided in each channel may be the same filter or different filters. Then, the master device 3 sequentially adds the low frequency data extracted from the channel data D1 to D5 to the woofer data D6, and transmits the woofer data D6 obtained by adding all the low frequency data to each slave device 4. To do. Also, the high frequency data extracted from the channel data D2 to D5 is transmitted to the slave device 4 corresponding to each channel.

  Each of the master device 3 and the slave device 4 is provided with an inverse characteristic filter RF that is an inverse characteristic of the output characteristic of each speaker 15. The master device 3 attenuates the high frequency data extracted from the channel data D1 through the inverse characteristic filter RF, and then amplifies the high frequency data with the amplifier AMP. Further, the woofer data D6 added with the low frequency data is attenuated through the inverse characteristic filter RF, added to the high frequency data amplified by the amplifier AMP, and output to the speaker 15. Each slave device 4 performs the same process on each of the high frequency data of each channel received from the master device 3 and the woofer data D6 obtained by adding the low frequency data.

  Next, each operation | movement of the master apparatus 3 and the slave apparatus 4 in this embodiment is demonstrated. FIG. 15 and FIG. 16 are flowcharts showing an example of processing procedures performed by the master device 3 and the slave device 4 in the present embodiment. Although only one slave device 4 is shown in the figure, the processing procedure of the other slave devices 4 is the same. In FIG. 15, the processing of steps S160 to S164 performed by the master device 3 and the processing of steps S260 to S264 performed by the slave device 4 are the same as those of steps S130 to S135 and steps S230 to S234 shown in FIG. Therefore, the subsequent processing will be described below.

  After transmitting the clock data, the master device 3 selects the music data 9 to be reproduced from at least one music data 9 stored in the memory 20 based on, for example, a user input operation (step S165). Then, the low frequency data and the high frequency data are separated from each channel data included in the selected music data 9 (step S166), and the low frequency data and the woofer data of each channel are added (step S167). And the output level (sound pressure level) at the time of reproducing | regenerating the data for woofers which added low frequency data with all the some portable terminal devices 2a-2e is calculated (step S168), and based on the output level, each channel is calculated. A gain to be applied to the high frequency data is calculated (step S169). Then, the high frequency data of the channel to be reproduced in each slave device 4 and the woofer data obtained by adding the low frequency data are extracted, and transmission to each of the slave devices 4 is started (step S170). Thereby, the high frequency data of the channel corresponding to the installation position and the woofer data obtained by adding the low frequency data of each channel are sent to each slave device 4 as individual music data. At this time, the master device 3 transmits a gain to be given to the high frequency data of each channel to each slave device 4. As a result, the slave device 4 starts receiving individual music data including the high frequency data transmitted from the master device 3 and the woofer data to which the low frequency data is added (step S265).

  Proceeding to the flowchart of FIG. 16, when the slave device 4 completes the reception of the individual music data, the slave device 4 performs data conversion between the high frequency data and the woofer data received from the master device 3 (step S266). Here, processing for attenuating each of the high frequency data and the woofer data is performed based on the inverse characteristic filter of the speaker 15 provided in the slave device 4. When the data conversion ends, next, a gain to be given to the high frequency data is set (step S267).

  On the other hand, when completing the data transmission to each slave device 4, the master device 3 performs data conversion between the high frequency data for the master device and the data for the woofer (step S171). Here, processing for attenuating each of the high frequency data and the woofer data is performed based on the inverse characteristic filter of the speaker 15 provided in the master device 3. When the data conversion is completed, next, a gain to be given to the high frequency data is set (step S172). The subsequent processing is the same as that in the flowchart shown in FIG.

  By performing the processing as described above, each of the master device 3 and the slave device 4 simultaneously starts playing the music. And in this embodiment, since the low sound part of low directivity included in each channel data of surround data is included in the woofer data and reproduced by all the mobile terminal devices 2a to 2e, the music reproduction with higher sound quality can be performed. Is possible.

  In addition, when this embodiment is compared with the second embodiment described above, as described above, the present embodiment is superior in that the music reproduction with higher sound quality can be performed. Then, since part of the channel data is separated and reproduced by all the mobile terminal apparatuses 2a to 2e, the surround feeling sensed by the user may be inferior to that of the second embodiment. Therefore, the user may be able to select which one of the reproduction method described in the second embodiment and the reproduction method according to the present embodiment is adopted.

(Modification)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the content mentioned above.

  For example, in each of the embodiments described above, the slave device performs data conversion on the music data (individual music data) received from the master device based on the inverse characteristic filter of the speaker 15, but this is not limitative. There is no. That is, the master device may perform data transmission to each slave device after data conversion of the individual music data. However, in this case, the master device needs to hold various parameters related to the inverse characteristic filter of the speaker 15 of the slave device in advance.

  Further, in each of the above-described embodiments, the case where the reproduction is started after the data conversion is completed in the master device or the slave device is illustrated. For example, in step S109 and step S110 in FIG. 6, reproduction is started when data conversion is completed and preparation is completed in all of the master device and the slave device. However, it is not always necessary to start reproduction after completing the data conversion for the entire music data. That is, the reproduction may be started when the first part of the data necessary for reproducing the music data is converted, and then the subsequent data conversion may be performed in parallel so as to be in time for reproduction. By doing so, there is an advantage that the data conversion and the reproduction process can be performed in parallel, and the time until the reproduction is started can be shortened.

  Further, for example, in the second embodiment and the third embodiment described above, when one of the plurality of mobile terminal devices 2a to 2e reproducing the surround data is detached, the woofer reproduced accordingly The sound pressure level of the sound may decrease, and the balance between the woofer sound and each channel sound may deteriorate. In order to prevent this, for example, after the reproduction of the surround data is started, the master device 3 monitors each slave device 4, and when one slave device 4 is detached, the master device 3 and the remaining device are left accordingly. It is preferable that the slave device 4 is configured to readjust the gain given to each channel data. Further, in this case, it is more preferable to redistribute the channel data that the detached slave device 4 is in charge of to the other slave devices 4.

  In the second embodiment and the third embodiment described above, 5.1ch surround data is reproduced on a plurality of mobile terminal devices 2a to 2e installed at five locations around the user. When the number of portable terminal devices is insufficient, for example, one portable terminal device is in charge of reproduction based on channel data for two channels of the rear right position and the rear left position, or the front center One mobile terminal device performs playback for a plurality of channels, for example, one mobile terminal device is responsible for playback based on channel data for three channels of the position, the front right position, and the front left position. What is necessary is just to comprise.

  Further, when there is a moving image to be reproduced along with the music reproduction, the moving image may be displayed on each portable terminal device, or only the master device 3 may display the moving image. Also good.

  Further, in the case where each portable terminal device acquires the program by downloading the above-described music reproduction program 8 from, for example, a download site, a plurality of types of programs are previously stored in the download site according to the model of the portable terminal device. It is preferable to prepare. As a result, each mobile terminal device can download a program corresponding to its own device, and in particular, the accuracy of the inverse characteristic filter of the speaker 15 can be increased.

1, 1a Music playback system 2, 2a, 2b, 2c, 2d, 2e Mobile terminal device (music playback device)
3 Master device 4 Slave device 8 Music playback program 9 Music data 15 Speaker 17 Wireless communication unit (communication means)
18 External interface (communication means)
19 CPU
20 memory (storage means)

Claims (11)

A piece of music that reproduces a piece of music based on the one piece of music data by the plurality of piece of music piece reproduction devices by performing reproduction processing based on at least one piece of individual piece of music data that constitutes one piece of piece of music data. A playback system,
Each of the plurality of music playback devices includes:
A speaker for sound output;
Storage means for storing individual music data to be reproduced in the device among at least one individual music data constituting the music data;
Data conversion means for attenuating the individual music data stored in the storage means based on the output characteristics of the speakers;
Reproducing means for synchronizing the reproduction timing with other music reproducing devices, reproducing individual music data attenuated by the data conversion means, and outputting from the speaker;
A music playback system comprising:   2. The music reproducing system according to claim 1, wherein the data converting means attenuates individual music data by an inverse characteristic filter of the frequency characteristic of the speaker. Each of the plurality of music playback devices further includes communication means for performing data communication with other music playback devices,
One of the plurality of music playback devices generates individual music data to be played back by each music playback device from the music data, and sends the individual music data to other music playback devices via the communication means. The music playback system according to claim 1 or 2, wherein the music playback system instructs transmission timing to another music playback device. The music data is surround data including low frequency data and one or more channel data,
4. The music playback system according to claim 1, wherein each of the plurality of music playback devices performs playback based on channel data and low frequency data assigned to each device. 5. The music data is surround data including low frequency data and one or more channel data,
Each of the plurality of music playback devices includes high frequency data extracted from channel data allocated to each device, and data obtained by adding low frequency data extracted from all channel data to the low frequency data. 4. The music playback system according to claim 1, wherein playback is performed based on the music playback. A speaker for sound output;
Storage means for storing individual music data to be reproduced in the device among at least one individual music data constituting one music data;
Data conversion means for attenuating the individual music data stored in the storage means based on the output characteristics of the speakers;
Communication means for synchronizing reproduction timing by performing data communication with other portable terminal devices;
Reproduction means for reproducing individual music data attenuated by the data conversion means at the reproduction timing and outputting from the speaker;
A portable terminal device comprising:   7. The portable terminal device according to claim 6, wherein the data conversion unit attenuates the individual music data by an inverse characteristic filter of the frequency characteristic of the speaker. The music data is stored in the storage means,
The number of music data to be played back is determined by performing data communication with other mobile terminal devices via the communication means, and individual music data to be played back in each mobile terminal device is generated from the music data. The portable terminal device according to claim 6 or 7, wherein the portable terminal device is transmitted to the portable terminal device, and the reproduction timing is instructed to another music reproducing device. The music data is surround data including low frequency data and one or more channel data,
Allocating low band data and at least one channel data to each portable terminal device based on the number of music data to be reproduced, and transmitting the assigned data to each portable terminal device via the communication means, The portable terminal device according to claim 8. The music data is surround data including low frequency data and one or more channel data,
Separate the high frequency data and low frequency data of each channel data and add the low frequency data obtained from all channel data to the low frequency data,
Based on the number of pieces of music data to be reproduced, each mobile terminal device is assigned low-frequency data added with low-frequency data and high-frequency data separated from at least one channel data. 9. The mobile terminal device according to claim 8, wherein data assigned to the mobile terminal device is transmitted. A music playback program executed by a mobile terminal device provided with a speaker, the mobile terminal device,
Storing at least one individual piece of music data constituting one piece of music data in a predetermined storage means;
Attenuating the individual music data stored in the storage means based on the output characteristics of the speaker;
Synchronizing the playback timing by performing data communication with other mobile terminal devices;
Reproducing the attenuated individual music data at the reproduction timing and outputting from the speaker;
A music reproduction program characterized in that the program is executed.

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