Patent Publication Number: US-6990382-B2

Title: Control system for digital sound effect and the method of the same

Description:
FIELD OF THE INVENTION 
   The present invention relates to a control system for digital sound effect, and more specifically, to a method and control system for home theater, the system allows the digital control code to be transmitted while transmitting the sound effect data to control the sound effect. 
   BACKGROUND OF THE INVENTION 
   Along with the rapid development of electronic industry, it is not uncommon to play films with advance sound and visual effects on computers anymore. Therefore, the requirement for video and audio performance has become more and more stringent. Except for the need of higher resolution and visual quality, in the field of audio frequency and sound effect, stereo sound effect has gradually replaced mono sound effect. However, the traditional stereo sound effect generates sound through lateral panning of sounds between two speakers to simulate the real three-dimensional sound source movements, and does not actually generate sounds in a three-dimensional space. Another type of surrounding sound generates three-dimensional sounds through multiple speakers, yet it is impossible to precisely locate sounds in a space. Therefore, the sound effect is unsatisfactory. 
   In recent years, head-related transfer function (HRTF) has been widely used in the field of three-dimensional sound locating technique. Because HRTF simulates the sound effect model heard by a human ear in a three-dimensional space and the parameters corresponding to the three-dimensional sound effect at every spot of the space are determined by its distance, azimuth, and elevation, the listener feel like within the real atmosphere of the sound while playing a film. However, the method of utilizing two sets of speakers to simulate three-dimensional sound effect still exhibits some shortcomings and limitations. For example, those speakers need better frequency response, the positions of the speakers need to be leveled with human ear, the locations of the listener and the speakers should be arranged so as to become an equilateral triangle, the rear surrounding effect should be realistic enough, and the sweet spot which is the area actually generating surrounding sound effect needs to be large enough, otherwise not all people within the space are able to enjoy the sound effect. Therefore, the structure of utilizing four or more speakers is then introduced. 
   Please refer to  FIG. 1A  of the prior art, the 5.1D sound system  10 A, widely used among family theaters, includes four satellite speakers, each at the front left, front right, rear left, and rear right directions of the listener  144   120 , i.e., front left (FL) speaker  110 , front right (FR)  112 , rear left (RL)  114 , rear right (RR)  116 , respectively, and with an additional sub woofer  118  to become a five-speaker system. Finally, the popular 5.1D sound system  10 A also includes a voice speaker  106  near the screen  104  to play front scene voices, such as the dialogues between actors. 
   Generally speaking, the family theater system stated above can be controlled by a computer system  102 , such as a personal computer (PC), through a sound control unit  1022  (e.g., a sound card) connected with three pairs of transmission lines  122 ,  124 , and  126  to transmit the sound effect data needed by the six stated speakers to a control circuit  108 A. Later on, the sound effect data is transferred to FL speaker  110 , FR speaker  112 , RL speaker  114 , RR speaker  116 , voice speaker  106 , and sub woofer  118  separately through transmission lines  128 ,  130 , 132 , 134 ,  136 , and  138  to generate sound. When the listener  120  watches film, listens to music, or plays computer game, the required three-dimensional sound effect can be realistically generated by the stated sound system  10 A. Among the stated speakers, except the sub woofer  118  is used to generate low frequency sound, all the other speakers, including FL speaker  110 , FR speaker  112 , RL speaker  114 , and RR speaker  116 , are used to play mid and high frequency sound. 
   Besides, the conventional sound system  10 A can only single-directionally receive and process the sound effect data from the computer system  102 , but it can&#39;t transmit its status data back to the computer system  102 , which is inconvenience while using. For example, human ear can&#39;t distinguish the directionality of low frequency sound and is insensitive to low frequency (e.g., 170 Hz) sound. In other words, the wattage of the sub woofer  118  has to increase a great deal for the human ear to sense the difference. On the contrary, human ear is quite sensitive to mid and high (e.g., 1–20 KHz) frequency sounds, therefore the wattage of general sub woofer  118  is much greater than other types of speakers, like the two stated speakers constructed in 40 and 5 watts. On the other hand, most conventional speakers need to be continuously kept at stand-by state and wait for the transmission of sound effect data in order to generate sounds. Therefore, about half (i.e., 50%) of the electrical power provided to the speakers is used to maintain the stand-by state and becomes dissipation heat in order to keep the speakers from burning up caused by overheating. Furthermore, while utilizing the stated speakers, if the listener  120  wants to adjust sound volume or sound quality or even switch the speakers on or off, the computer system  102  is lacking the related assisting user interface or accessories, so as that the listener  120  has to be in front of a speaker and lowers his or her body (or even lie on the floor) to adjust the speaker through control buttons. Some high-end sound and audio systems are equipped with additional extension wires to simplify the adjusting procedure. However, when the listener  120  needs to adjust the sound effect of entire sound field, all speakers need to be undergoing constant adjustment, which is a very inconvenient process. There is a great need for easier sound control system and method in order to overcome the difficulties faced by the prior art. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to disclose a control method for sound effect system. 
   The further object of the present invention is to implant a control code into sound effect data to control the speaker parameters. 
   The yet object according to the present invention is to provide a communication between the computer system and a sound effect system. 
   A control method for controlling the sound effect system, comprises implanting a control code into a sound effect data that is transmitted to a sub woofer speaker. Then, the sound effect data with the control code is transmitted to the sound effect system. Next step is to control speakers of the sound effect system by means of the control code. Wherein a data transmission frame between the sound effect system and a computer system for controlling the sound effect system comprises a plurality of bit cells, wherein the data transmission frame includes: a sound effect data transmitted by a data bit; and a control code transmitted by a control bit. 
   Each the data bit and the control bit is further divided by two sub-units comprises: 
   a first sub-unit of the data bit used to store a sound effect data transmitted from the computer system to the sound effect system; 
   a second sub-unit of the data bit used to store a status data transmitted back to the computer from the sound effect system; 
   a third sub-unit of the control bit used to store a control code transmitted from the computer system to the sound effect system, wherein the control code includes reset pattern; and 
   a fourth sub-unit of the control bit used to store a confirming code transmitted back to the computer from the sound effect system, wherein the confirming code is used to make sure that the computer system and the sound effect system are in the status of synchronization. 
   A sampling timing for the controlling method comprises: a first timing cycle utilized to indicate the beginning of data string, each the first timing cycle maintaining at “logic one level”. The computer system indicates the signal by “logic 1” or “logic 0” using a voltage level to transmit data to the sound effect system during the second timing cycle. During the third and the fourth timing cycle, the voltage levels are floating, thus a voltage output by the computer system is slightly higher than the level of “logic 0”. The sampling timing is generated by the phase lock loop (PLL). The third timing cycle is detected by a phase detector (PHD), a mask signal (“logic zero”) is generated to input to an AND GATE via a transmission line, thereby maintaining the voltages level of the transmission line at low level during the third timing cycle to prevent the PLL from being interrupted. 
   The method further include: fetching the transmitted data by using a data decoder and a timing recorder; composing the fetched transmitted data to from the sound effect data and the control code; and transmitting the sound effect data and the control code to means for playing the sound effect and to means defined by the control code. 
   The method further comprises following steps to obtain the synchronization frame status between the computer system and the sound effect system: 
   transmitting a reset pattern from the computer system to the sound effect system by suing a transmission line of the sub woofer speaker; 
   fetching the reset pattern from the transmission line of a sub woofer speaker by the sound effect system; 
   recognizing the fetched reset pattern by the sound effect system, if the reset pattern is recognized, then transmitting a synchronization confirming code to the computer system; 
   fetching the confirming code from the sound effect system by the computer system; and 
   recognizing the confirming code, if the confirming code is correct, then transmitting control code to the sound effect system. 
   A control system for controlling a sound effect system by using a digital control signal, comprising a computer system for generating a control code and a sound effect data to control the sound effect system. A control circuits is implanted in the sound effect system to control a playing parameter of the sound effect system according to the control code and the sound effect data. Wherein the control circuits generates a sampling timing in accordance with the control code, thereby creating frame synchronization between the computer system and the sound effect system, wherein the control code is implanted into the sound effect data that is transmitted to a sub woofer speaker. 
   Wherein each the data bit and the control bit is divided by two sub-units comprises: 
   a first sub-unit of the data bit used to store the sound effect data transmitted from the computer system to the sound effect system; 
   a second sub-unit of the data bit used to store a status data transmitted back to the computer from the sound effect system; 
   a third sub-unit of the control bit used to store a control code transmitted from the computer system to the sound effect system, wherein the control code includes reset pattern; and 
   a fourth sub-unit of the control bit used to store a confirming code transmitted back to the computer from the sound effect system, wherein the confirming code is used to make sure that the computer system and the sound effect system are in the status of synchronization. 
   The computer system includes sound effect control unit, the sound effect control unit comprising a PLL (phase lock loop) including a phase detector (PHD) used to generate the sampling timing. A timing recorder is responsive to the phase detector (PHD) to generate a timing signal. A data encoder is responsive to the timing signal to encode a status information of the sound effect system in order to transmit to the computer system via the sub woofer speaker. A data decoder is responsive to the timing signal to decode the control code transmitted via the sub woofer speaker. 
   A sampling timing is generated by the phase lock loop for controlling, wherein the sampling timing comprises a first timing cycle utilized to indicate the beginning of data string, each the first timing cycle maintaining at “logic one level”. A computer system indicates the signal by “logic 1” or “logic 0” using a voltage level to transmit data to the sound effect system during the second timing cycle. During the third and the fourth timing cycle, the voltage levels are floating, thus a voltage output by the computer system is slightly higher than the level of “logic 0”. The third timing cycle is detected by the phase detector (PHD), a mask signal (“logic zero”) is generated to input to an AND GATE via a transmission line, thereby maintaining the voltages level of a transmission line at low level during the third timing cycle to prevent the PLL from being interrupted. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1A  is architecture of a conventional 5.1 D home theater sound effect system. 
       FIG. 1B  is architecture of the present invention 5.1 D home theater sound effect system. 
       FIGS. 2A–2C  are data transmission frames according to the present invention. 
       FIG. 3  is control circuits architecture of the present invention. 
       FIGS. 4A–4G  are the waveforms of the data transmission according to the present invention. 
       FIGS. 5A–5B  are the process flow charters according to the present invention. 
   

   THE DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Turning to  FIG. 1B , it illustrates the home theater 5.1D sound effect system according to the present invention. The transmission line  122 A of the sub woofer speaker  118  coupled between the control circuits  108 B of the sound effect system  10 B and the computer system or the computer system  102  for dual way transmission. The transmission line  122 B transmits the sound data from the computer system  102  to the speaker. The sub woofer speaker  118  performs the sound signal with 170 Hz, there is vacant band width can be used during the sound signal is under transmission. The typical used output source is the sampling with 16 bits resolution and 44.1 KHz. The band width under such base is: 44.1 KHz×16 bits=705 kbits. If the 256 times band width is used for the oversampling output, and the sound effect information and digital control code uses one bit for transmitting the data, thus the data transmission band width of the sub woofer speaker  118  is: 705 kbits÷256÷2=1.38 kHz. Obviously, the 1.38 kHz is wider than the required bandwidth of the transmitting frequency (170 Hz) of the sub woofer speaker  118 . The present invention uses the transmission line  122 A to transmit the control code to the sound effect system  10 B. Further, even the higher sampling is used, such as 512 times band width for the oversampling, the present invention may be utilized for transmitting the digital control signal only make sure that the sub woofer speaker  118  will not be distortion. The present invention discloses a system and method for transmitting control code while transmitting the sound effect data. 
     FIG. 2A  shows the data transmission frame according to the present invention. The data transmission frame refers to reset pattern for synchronizing the computer system  102  and the sound effect system  10 B. 32 bits construct the data transmission frame. The data transmission frame is divided by sound effect data transmitted by data bit  202  and the digital control code transmitted by control bit  204 . The data bit  202  and the control bit  204  are respectively indicated by “D” and “C” located on the corresponding bits. Each data bit  202  and the control bit  204  is further divided by two sub-units. The first sub-unit  202 A of the data bit  202  is used to store the sound effect data that is transmitted from the computer system  102  to the sound effect system  10 B. While the second sub-unit  202 B of the data bit  202  is used to store the status data that is transmitted back to the computer system  102  from the sound effect system  10 B. Similarly, the first sub-unit  204 A is used to store the control code that is transmitted from the computer system  102  to the sound effect system  10 B. The second sub-unit  204 B of the control bit  204  is used to store the confirming code that is transmitted back to the computer system  102  from the sound effect system  10 B. The confirming code is used to make sure that the computer system  102  and the sound effect system  10 B are in the status of frame synchronization. 
   Further, in the  FIG. 2A , the computer system  102  transmits the reset pattern of the control code “00A5” in the control bit  204  to the sound effect system  10 B. Wherein the “00A5” is constructed by 16 bits and respectively locate in each first sub-unit  204 A of the control bit  204 , sequentially. The sound effect data and the frame synchronization confirming code are belong to the “Don&#39;t care term”,which is indicated by “x” in  FIG. 2A . The sound effect system  10 B filters the reset pattern of the “00A5” from the transmitted frame, and further transmitting the synchronization confirming code “00FF” back to the computer system  102 . The reset pattern is extreme important due to the method uses one pin  122 A to transmit the digital control code. Thus, the computer system  102  must continually transmit the reset pattern so as for the sound effect system  10 B may self-reset while recognize the reset pattern. The transmission of synchronization confirming code to the computer system  102  may make sure that the sound effect system is frame synchronization with the computer system  102 . Thus, the computer system  102  and the sound effect system  10 B may transmit data with each other, the transmitted data is shown in  FIG. 2C  as an example. As shown in  FIG. 2C , the transmitted sound effect data includes “C71D”,and the control code is “3C5A”. Thus, after the sound effect system  10 B receives the sound effect data “C71D” transmitted from the computer system  102 , the control circuits  108 B according to the control code “3C5A” controls the sound effect performed by the speaker when the speaker receiving the sound effect data “C71D”. 
   It has to be noted, the computer system  102  may transmits the reset pattern to the sound effect system  10 B, continuously, and it may set a predetermined threshold in order to wait for the sound effect system  10 B transmits back the synchronization confirming code. When the transmission delaying time (or the number of transmission times) of the transmitted reset pattern is over the threshold, then the computer system  102  transmits the sound effect data by using the conventional method as shown in  FIG. 1A . Further, the computer system  102  may add “A5” reset pattern in the latter portion of each digital control code to define that the transmitted data is completed. The division of the control code may be variation depending on the actual practice. For example, the control code may be divided into former portion with 10 bits and latter with 6 bits. The bit number of the control code can be increased to 64 bits or more. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims. 
   The control code may be further divided. For example, the “3C” in the control code “3C5A” may be divided into “00111110”, the former three bits “001” is used as the speaker code and others “11110” is used for the control code to control the vibration of the speaker. In an embodiment, the sub woofer speaker  118 , FL-speaker  110 , FR-speaker  112 , RL-speaker  114 , RR-speaker  116  and the voice speaker  106  may be coded as “000”, “001”, “010”, “011”, “100”and “101”, respectively. The aforementioned control code “ 001 ” refers to the FL-speaker  110 . The definition of the code maybe altered depending on the actual practice. For example, “11110” refers to changing the volume level to 30th level (total 32 volume levels). The above control code “3C” is referred to adjusting the volume level of the FL-speaker  110  to 30th level. Each individual speaker may be controlled by the computer system  102 , the user may adjust the playing parameters of each speakers by means of computer system  102 . Therefore, the user may change the effect performed by the speakers depending on the locations of each speaker. After the decoding of the control code, the sub woofer speaker  118 , FL-speaker  110 , FR-speaker  112 , RL-speaker  114 , RR-speaker  116 , the voice speaker  106 , volume level and the power are controlled via the transmission line  128 ,  130 ,  132 ,  134 ,  136  and  138 . When the bit number of the reset pattern is reduced to 6 bits, the sound effect system  10 B has more vacant bits for speaker playing parameter such as volume level, sound quality and power status. 
   Next turning to  FIG. 4A–4G , the drawings illustrates the voltage waveform while transmitting the data.  FIG. 4A  illustrates the sampling waveform CLK — S that is the synchronization timing of the computer system  102  and the sound effect system  10 B.  FIG. 4B  is the output voltage level waveform of the computer system  122 .  FIG. 4C  is the output voltage level waveform of the sound effect system  10 B.  FIG. 4D  is the composition waveform of  FIG. 4B  and  FIG. 4C . The present invention uses four-times bandwidth to transmit and receive data, as known in the art, other band width may be used such as eight-times band width. 
   The signal transmitted on the transmission line  122 A is divided into four portions by four times sampling timing CLK — S shown in  FIG. 4A . Wherein the second timing cycle  404  falling edge  410  of the sampling timing CLK — S is the sound effect data from the computer system  102  to sound effect system  10 B. Similarly, the third timing cycle  406  falling edge  412  of the sampling timing CLK — S is the data from sound effect system  10 B to the computer system  102 . The sampling timing CLK — S&#39;s first timing cycle  402  is used as the recognition code to define the beginning of data string. Thus, during each sampling timing CLK — S&#39;s first timing cycle  402 , the voltage level of transmission line  122 A maintains at “logic 1”. The signal carried by the transmission line  122 A includes the data transmitted between the computer system  102  and the sound effect system  10 B. The computer system  102  has to indicate the signal by “logic 1” or “logic 0” using the voltage level to transmit the data to sound effect system  10 B during the sampling timing CLK — S&#39;s second timing cycle  404 . During the third and fourth timing cycle  406 ,  408 , the voltage levels are floating, thereby voltage output by the computer system  102  is slightly higher than the level of “logic 0”. Further, the first timing cycle  402  is utilized to indicate the beginning of data string, thus each first timing cycle  402  maintains at high level and the waveform is shown in  FIG. 4B . 
   On the another hand, during the first timing cycle  402  and the second timing cycle  404 , the sound effect system  10 B fetches the data from the transmission line  122 A and the output is set at the status of floating. Besides, the third timing cycle  408  of the sound effect system  10 B also floating and the waveform of the sound effect system  10 B is shown in  FIG. 4C . Apparently, the waveform of the transmission line  122 A is the composition of the  FIG. 4B and 4C  and the result is illustrated in  FIG. 4D . The fourth timing cycle  408  maintains floating indicated by  414 . It is important for floating during the fourth timing cycle  408  due to each bit cell&#39;s first timing cycle  402  has to maintain at high voltage level to distinguish each cell. 
     FIG. 4A–4D  illustrates the waveform of the two data bit cells DI and DII and the control bit cell CI and CII. The transmission line is sampling at the falling edges  410 ,  412  of the second and third timing cycle  404 ,  406  in each bit cell, S h  and S s  are respectively used to indicate the data that comes from the computer system  102  or sound effect system  10 B. For example, When the sampling at the falling edge  410 ,  412  in the bit cell DI is taken, the level is “logic zero”. It defines that the data of bit cell DI includes “S h =S s =0”. Similarly, the data of bit cell DII includes “S h =0, S s =1”. The data of control cell CI includes “S h =0, S s =1” and the data of control cell CII includes “S h =1, S s =1”. 
   Next, please turn to  FIG. 3 , it illustrates the circuit architecture for control circuits  108 B transmits and receives data by transmission lines  122 A. The transmission between the computer system  102  and the sound effect system  10 B only uses one-transmission line  122 A. If the synchronization timing can not be transmitted, the control circuits  108 B has to generate the same synchronization sampling timing CLK — S with the one of the computer system  102  in the sound effect system  10 B via the voltage of the transmission line  122 A. The internal oscillator can generate the sampling timing CLK — S of the computer system  102 . The transmission line uses the node  302  of one or Wire-OR to compose the signal from the computer system  102  and the sound effect system  10 B. After the Logic AND calculates the signal fed from the AND gate  304  and the transmission line  324 . The result is output to PLL (phase lock loop)  306  by transmission line  318  to generate sampling timing CLK — S. Basically, the control circuits  108 B uses PLL  306  and divider  308  to generate sampling timing CLK — S in the sound effect system  10 B. The PLL  306  includes phase detector (PHD)  3062 , loop filter (LF)  3064  and voltage controlled oscillator (VCO)  3066 . As matter of fact, any type of PLL may be applied in the present invention. In the case of four-times sampling CLK — S, the divider  308  is a four-divider. 
   The control circuits  108 B fetches the data transmitted by the transmission line  324  via the data decoder  312  and timing recorder  310 . After the data of the data transmission frame is fetched, all of the data are composition to from sound effect data and control code, following transmitting by transmission lines  334 ,  336  to the means for playing the sound effect  316  and to the controlled unit defined by the control code. For example, the “A5” of the control code “3CA5” is used for resetting pattern and the “3C” is used to adjust the volume level of the FL speaker  110  to the 30th level. As aforementioned, the control circuits also includes data encoder  314  to transform the status information and synchronization confirming code of the sound effect system  10 B into binary format. When at the falling edge  412  timing recorder  310  transmits the data by transmission line  320  and further transmission the data to computer system  102  via the transmission line  122 A. 
   It has to be note, when the data encoder  314  outputs high level (logic one) during the third timing cycle  406  of the timing CLK — S, the high voltage level pushes the PLL  306  to the status of reset and resulting a calculation error is generated. In order to prevent the issue from being generated, the timing records  310  at the third timing cycle  406  of the timing CLK — S detected by the phase detector (PHD)  3062 , a mask signal (“logic zero”) is generated to input to AND GATE  304  via transmission line  324 . This makes the voltages level of the transmission line  318  maintains at low level at the third timing cycle  406  of the timing CLK — S, thereby preventing the PLL  306  from being interrupted.  FIG. 4E ,  4 F and  4 G shows the voltage waveforms of the transmission lines  332 ,  324 ,  318 . The means for playing sound effect  316  may play the fetched sound effect data, such as directly plays the signal through the DAC (digital-analog converter) or after oversampling. The data encoder  314  encodes the data in accordance with the S fl –S fn  signals, after transforms to binary format the signal is transmitted to the computer system  102  by transmission line  320 ,  122 A. The S fl –S fn  represents the status of the sound effect system  10 B such as the speaker is power on or not, the system is in green mode or not and so on. Logic gates may construct the timing recorder  310 , data encoder  314  and the data decoder  312 . 
     FIG. 5A  illustrates the preferred embodiment of the present invention, it illustrates the flow chart to obtain the synchronization status for the computer system  102  and the sound effect system  10 B.  FIG. 5B  illustrates the flow chart to transmit between the computer system  102  and the sound effect system  10 B after synchronization status. It should be note that the transmission of the control code, the status information will be processed after synchronization. If the transmission of the reset patter over the threshold, the computer system  102  will transmit the information by conventional method. 
   Turning to  FIG. 5A , in step  502 , the computer system  102  transmits the reset pattern to the control circuit  108 B of the sound effect system  10 B via the transmission line  122 A of the sub woofer speaker  118 . Next, the sound effect system  10 B fetches the reset pattern from the transmission line  122 A in step  504 . Then, the sound effect system  10 B, in step  506 , recognizes the fetched reset pattern. If the reset pattern is recognized, then the step  508  is processed to transmit the synchronization confirming code to the computer system  102 . Otherwise, back to step  502 , the computer system  102  transmits the reset pattern to the sound effect system  10 B again. Subsequently, the computer system  102  in step  510  fetches the confirming code from the sound effect system  10 B, followed by processing step  512  to recognize the confirming code. When the confirming code is incorrect, then backs to step  502  and processes the steps  502 - 510 . On the contrary, if the confirming code is correct, then processing the next step shown in  FIG. 5B  via node A. 
     FIG. 5B  illustrates the flow chart of operating the computer system  102  and sound effect system  10 B, respectively. The computer system  102  and sound effect system  10 B respectively fetches and transmits the data by means of sampling timing CLK — S, therefore, the two individual system will not interrupt with each other. 
   After the synchronization, in step  514 , the computer system  102  locates the control code needed by the sound effect system  10 B into the sound effect data of the sub woofer speaker  118 , and the data is transmitted to the sound effect system  10 B via the transmission line  122 A. All of the signals are respectively transmitted to each speaker via corresponding transmission line. The computer system  102  in step  516  fetches the confirming code and status information transmitted from the sound effect system  10 B. Next, the computer system  102  analyzes the confirming code and status information in step  518 . Step  520  is to process the necessary function according to the analysis. Step  530  is to determine the playing process is end or not, if the determination is negative, then repeating the flow of steps  514 – 520 . 
   In step  522 , after the sound effect system  10 B receives all of the signals for each speaker. The sound effect system  10 B fetches the control code by the transmission line  122 A of the sub woofer speaker. Then, the sound effect system  10 B transmits the confirming code and status information to the computer system  102  via the transmission line  122 A in step  526 . Next, in step  526 , the sound effect system  10 B adjusts the status or playing parameter of the speakers, such as volume and the power status, by the instruction of the control code. The speakers perform the data send from the sound effect system  10 B. Next step  530  is to determine the playing process is end or not, if the determination is negative, then repeating the flow of steps  514 – 520 . 
   As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structure. While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.