Abstract:
The present invention relates to a speaker, and a method and surround sound system for processing multi-channel audio signals in each of a plurality of audio output sources for generation of surround sound in a listening area. In particular, the system comprises a transmitter for transmitting a left channel (L) signal and a right channel (R) signal to a speaker. The speaker comprises a processing unit configured to (a) receive an audio signal having a left channel (L) signal and a right channel (R) signal; (b) process separately and independently the L and R audio signals to produce processed signals; and (c) mix the processed signals to produce the surround sound signal.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a speaker. In particular, it also relates to a method and surround sound system for processing multi-channel audio signals in each of a plurality of audio output sources for generation of surround sound in a listening area. 
       BACKGROUND OF THE INVENTION 
       [0002]    Existing surround sound recording formats include those referred to as 5.1, 6.1 and 7.1. The 5.1 surround format comprises a compressed data stream containing five channels, generally designated left, center, right, surround left, and surround right, named for the speaker positions for which the channel information is intended. A low frequency effects channel is formed by a combination of the five other channels, and may be provided to a sub-woofer. The 6.1 surround format includes the same five channels as the 5.1 surround format, but adds a surround back channel, which may be fed to one or more back speakers in a surround sound system. The 7.1 surround format is similar to the 5.1 surround format, but has two surround side channels (surround side left and surround side right) rather than a single back channel, for a total of seven channels. Thus, the 5.1 surround format has two surround channels (surround left and right), the 6.1 surround format has three surround channels (surround left, right and back), and the 7.1 surround format has four surround channels (surround side left and right, and surround back left and right). 
         [0003]    Basic surround system speaker configurations generally include from six to eight speakers placed at conventionally well-established locations, according to the type of surround format they are intended to play. A six-speaker surround system typically includes left, right and center speakers (with the right and left speakers spaced widely apart), a sub-woofer, and surround left and right speakers (which may be monopolar or dipolar in nature). A seven-speaker surround system typically includes the same speaker arrangement as the six-speaker surround system, but adds a back surround speaker. An eight-speaker surround system typically includes the same speaker arrangement as the six-speaker surround system, but adds a back left surround speaker and a back right surround speaker. 
         [0004]    The enjoyment experienced by a listener in a surround sound system can be affected by a number of factors, including the listener&#39;s physical position relative to the various speakers, as well as by the particular format of the audio track being played on the system. 
         [0005]    However, there are problems in the abovementioned conventional surround sound systems. For example, conventional 7.1 systems are not capable of being expanded, i.e. the number of speakers cannot be increased. Therefore, a user does not have the flexibility of adding speakers or changing the configuration of speakers in accordance with the user requirements. Further, conventional 7.1 systems have complicated wiring set-up procedures and it is difficult for a novice person to set up such systems easily. However, wired connections are necessary in setting up conventional surround sound systems because the signals after being processed and amplified in an audio/video receiver and amplifier unit are too large to be transmitted to output sources. 
         [0006]    Wireless solutions have been developed for stereo systems. However, present wireless systems only provide for the transmission of audio signals between one transmitter and one receiver. Disadvantageously, this system requires the use, of multiple transmitters. Still further, conventional stereo systems cannot be transformed or converted to generate surround sound because the stereo systems are not capable of digital signal processing. By doing so, the sound quality, and ultimately the surround sound experienced by a listener, deteriorates. 
         [0007]    Accordingly, it would be advantageous to provide an improved surround sound system which overcomes one or more of the foregoing problems or shortcomings. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with a first aspect of the present invention, there is provided a speaker for generating a surround sound signal, the speaker comprising a processing unit configured to: (a) receive an audio signal having a left channel (L) signal and a right channel (R) signal; (b) process separately and independently the L and R audio signals to produce processed signals; and (c) mix the processed signals to produce the surround sound signal. 
         [0009]    By “mix”, it is meant to include any audio mixing process known to the skilled person. Without undue limitation, it includes the mixing of audio signals by which a multitude of audio signals may be combined into one or more channels, most commonly two-channel stereo. By “surround sound signal”, it is meant to include the audio output produced by the processed audio signals. It is also meant to include one, two (for example, left and right audio signals) or any number of signals that is generated to produce the surround sound signal. 
         [0010]    Preferably, the processing unit is further configured to filter the received audio signal such that the output surround signal is filtered. 
         [0011]    Preferably, the processing unit is further configured to process the received audio signal according to one of: an equalisation characteristic; and a dynamic range characteristic. 
         [0012]    Preferably, the speaker further comprises an amplifier configured to amplify the processed signals. 
         [0013]    Preferably, the processing unit includes a wireless receiver to receive the L and R signals. 
         [0014]    Preferably, the left channel signal has a junction which splits the left channel signal into a first portion and a second portion. More preferably, the first portion signal is processed by a high pass filter, an equaliser, an all pass filter and a dynamic range control; and the second portion signal is processed by a high pass filter, an equaliser, a low pass filter and a dynamic range control. 
         [0015]    Preferably, the speaker comprises left and right drivers, and the processed left and right channel signals are channelled to left and right drivers respectively. More preferably, the processed right channel signal channelled to the right driver is out of phase to the processed left channel signal channelled to the right driver. 
         [0016]    Preferably, the high pass filter is configured to have a cut-off frequency of 70-200 Hz. More preferably, the high pass filter is configured to have a cut-off frequency of 200 Hz. 
         [0017]    Preferably, the low pass filter is configured to have a cut-off frequency of 1200 Hz. 
         [0018]    Preferably, the speaker is coupled to a sub-woofer unit, the sub-woofer unit comprises a low frequency effects channel formed by a combination of the L and R audio signals. 
         [0019]    Preferably, the sub-woofer unit comprises a processing unit including any one selected from the group: a high pass filter, a low pass filter, an equaliser, and a dynamic range control. 
         [0020]    Preferably, the low pass filter has a cut-off frequency of 70-200 Hz. 
         [0021]    Preferably, the sub-woofer has 12 dB boost at about 180 Hz. 
         [0022]    In accordance with a second aspect of the present invention, there is provided a method for generating a surround sound signal in a speaker, the method comprising: (a) receiving an audio signal having a left channel (L) signal and a right channel (R) signal; (b) processing separately and independently the L and R signals to produce processed signals; and (c) mixing the processed signals to produce the surround sound signal. 
         [0023]    Preferably, the processing includes: (a) filtering the L and R input signals; (b) controlling a dynamic range of the filtered signals; and (c) amplifying the processed signals. 
         [0024]    Preferably, the signals are processed by any one selected from the group: a high pass filter, a low pass filter, all pass filter, an equaliser, and a dynamic range control. 
         [0025]    Preferably, the left channel signal is split into a first portion and a second portion. More preferably, the first portion signal is processed by a high pass filter, an equaliser, an all pass filter and a dynamic range control; and the second portion signal is processed by a high pass filter, an equaliser, a low pass filter and a dynamic range control. 
         [0026]    Preferably, the processed left and right channel signals are channelled to left and right drivers respectively. More preferably, the processed right channel signal is channelled to the right driver out of phase to the processed left channel signal channelled to the right driver. 
         [0027]    Preferably, the high pass filter filters the signal at a cut-off frequency of 70-200 Hz. 
         [0028]    Preferably, the high pass filter filters the signal at a cut-off frequency of 200 Hz. 
         [0029]    Preferably, the low pass filter filters the signal at a cut-off frequency of 1200 Hz. 
         [0030]    Preferably, the audio signals are transmitted to the speaker wirelessly. 
         [0031]    Preferably, a portion of the left channel signal and right channel signal is transmitted to a sub-woofer unit. 
         [0032]    Preferably, the signals received by the sub-woofer unit are processed by any one selected from the group: a high pass filter, a low pass filter, an equaliser, and a dynamic range control. 
         [0033]    Preferably, the low pass filter filters the signal at a cut-off frequency of 70-200 Hz. 
         [0034]    Preferably, the signals are transmitted to the sub-woofer unit wirelessly. 
         [0035]    In accordance with a third aspect of the present invention, there is provided a surround sound system, the system comprising a transmitter for transmitting a left channel (L) signal and a right channel (R) signal to a speaker according to the first aspect of the present invention. 
         [0036]    Preferably, the system comprises 7 speakers. 
         [0037]    Preferably, the speakers are located in a single speaker enclosure. 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0038]    In order that the present invention may be fully understood and readily put into practical effect, there shall now be described by way of non-limitative examples only preferred embodiments of the present invention, the description being with reference to the accompanying illustrative figures. 
           [0039]    In the Figures: 
           [0040]      FIG. 1  shows a schematic diagram of the system according to an embodiment of the invention; 
           [0041]      FIG. 2A  shows a block diagram of the components of a front right processing unit according to an embodiment of the invention; 
           [0042]      FIG. 2B  shows a gain-frequency plot for a high pass filter of the front right processing unit of  FIG. 2A ; 
           [0043]      FIG. 2C  shows a gain-frequency plot for a first low pass filter of the front right processing unit of  FIG. 2A ; 
           [0044]      FIG. 2D  shows a gain-frequency plot for a second low pass filter of the front right processing unit of  FIG. 2A ; 
           [0045]      FIG. 3  shows a block diagram of the components of a front right processing unit according to an embodiment; 
           [0046]      FIG. 4A  shows a block diagram of the components of a front left processing unit according to an embodiment; 
           [0047]      FIG. 4B  shows a gain-frequency plot for a high pass filter of the front left processing unit of  FIG. 4A ; 
           [0048]      FIG. 4C  shows a gain-frequency plot for a first low pass filter of the front left processing unit of  FIG. 4A ; 
           [0049]      FIG. 4D  shows a gain-frequency plot for a second low pass filter of the front left processing unit of  FIG. 4A ; 
           [0050]      FIG. 5  shows a block diagram of the components of a front left processing unit according to an embodiment; 
           [0051]      FIG. 6A  shows a block diagram of the components for a front center processing unit according to an embodiment; 
           [0052]      FIG. 6B  shows a gain-frequency plot for a high pass filter of the front center processing unit of  FIG. 6A ; 
           [0053]      FIG. 7  shows a block diagram of the components for a front center processing unit according to an embodiment; 
           [0054]      FIG. 8  shows a block diagram of the components for a side right processing unit according to an embodiment; 
           [0055]      FIG. 9  shows a block diagram of the components for a side left processing unit according to an embodiment; 
           [0056]      FIG. 10  shows a block diagram of the components for a rear right processing unit according to an embodiment; and 
           [0057]      FIG. 11  shows a block diagram of the components for a rear left processing unit according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0058]      FIG. 1  shows a surround sound system  100  according to an embodiment. The system  100  may be wired or without wire. In other words, the transmission of audio signals in the system  100  may be carried out by means of a wire or by any wireless means known to the skilled person. The system  100  has a signal source  101  wirelessly connected to a plurality of speakers, and a subwoofer  109  for surround sound generation. The signal source  101  may be a stereo source  101 . The speakers include a front left speaker  102 , a front center speaker  103 , a front right speaker  104 , a side left speaker  105 , a side right speaker  106   m  a rear left speaker  107 , a rear right speaker  108 . The stereo source  101  is capable of generating stereo audio signals such as two channel stereo input signals namely, a left channel input signal  111  and a right channel input signal  112 . 
         [0059]    In the front left speaker  102 , there is a wireless receiver for receiving the left channel input signal  111  and the right channel input signal  112 , a front left processing unit  113 , and an amplifier unit  114 . 
         [0060]    Similarly, the front center speaker  103  has a wireless receiver for receiving the left channel input signal  111  and the right channel input signal  112 , a front center processing unit  117 , and an amplifier unit  118 . 
         [0061]    The front right speaker  104  has a wireless receiver for receiving the left channel input signal  111  and the right channel input signal  112 , a front right processing unit  121 , and an amplifier unit  122 . 
         [0062]    The side left speaker  105  has a wireless receiver for receiving the left channel input signal  111  and the right channel input signal  112 , a side left processing unit  125 , and an amplifier unit  126 . 
         [0063]    The side right speaker  106  has a wireless receiver for receiving the left channel input signal  111  and the right channel input signal  112 , a side right processing unit  129  and an amplifier unit  130 . 
         [0064]    The rear left speaker  107  has a wireless receiver for receiving the left channel input signal  111  and the right channel input signal  112 , a rear left processing unit  133 , and an amplifier unit  134 . 
         [0065]    The rear right speaker  108  has a wireless receiver for receiving the left channel input signal  111  and the right channel input signal  112 , a rear right processing unit  137 , and an amplifier unit  138 . 
         [0066]    The subwoofer  109  has a wireless receiver for receiving the left channel input (Lin) signal  111  and the right channel input (Rin) signal  112 , a subwoofer processing unit  141 , and an amplifier unit  142 . In all embodiments, the subwoofer  109  is used for generating low frequency components of the input signals  111 ,  112  to be sent to all the speakers  102 ,  103 ,  104 ,  105 ,  106 ,  107 ,  108  which are connected wirelessly to the subwoofer  109 . 
         [0067]    In the above speakers  102 ,  103 ,  104 ,  105 ,  106 ,  107 ,  108  and subwoofer  109 , the wireless receiver may be a Blue Tooth interface and configured within the respective processing unit of the speakers  102 ,  103 ,  104 ,  105 ,  106 ,  107 ,  108  and subwoofer  109 . 
       Front Right Process Unit 
       [0068]      FIGS. 2A to 2D  illustrate a front right (FR) process unit  121  of the front right (FR) speaker  104  according to an embodiment. 
         [0069]      FIG. 2A  shows a block diagram of the components of a front right (FR) process unit  121  (Option ‘A’) for generating a first front right (FR) signal  123  and a second front right (FR) signal  124 . The FR process unit  121  is configured to receive the Lin and Rin signals  111 ,  112  wirelessly, and process the L and R signals separately and independently, and eventually produce the output which is the surround sound signal comprising first front right (FR) signal  123  and a second front right (FR) signal  124 . The Lin signal  111  is divided or split into a first signal  203  and a second signal  204  at node  243 . 
         [0070]    In a separate signal path, the first signal  203  of the Lin signal  111  is passed through a series of components consisting of: a first High Pass Filter (HPF1)  206 , a first Equalization Filter (EQ1)  212 , a second Low Pass Filter (LPF2)  218 , and a first Dynamic Range Control (DRC1)  224 . The amplitude of low frequency components of the first signal  203  are attenuated by the HPF1 ( 206 ). In particular,  FIG. 2B  shows a gain—frequency plot  231  of the HPF  206  which illustrate a curve  234 . The curve  234  shows that the HPF1 ( 206 ) has a cut-off frequency of 70 to 200 Hz. In other words, the amplitude or gain of frequency components having a frequency of 70 to 200 Hz in the first signal  203  will be reduced to generate a filtered signal  209 . 
         [0071]    After the low frequency components are filtered, the filtered signal  209  is then directed to the EQ1 ( 212 ) for adjusting of the high frequency components of the filtered signal  209  to generate an equalized signal  215 . The equalized signal  215  is passed to the LPF2 ( 218 ) having a cut-off frequency of 1200 Hz.  FIG. 2C  show a gain-frequency plot  235  of the LPF2 ( 218 ) having a curve  238  for the LPF2 ( 218 ) showing the cut-off frequency of 1200 Hz. As such, the gain of frequencies above 1200 Hz in the equalized signal  215  will be reduced to generate a second filtered signal  221 . The second filtered signal  221  is passed to the DRC1 ( 224 ) to apply an appropriate gain so as to generate a first processed signal  226 . 
         [0072]    Similar to the processing of the Lin signal  111 , the Rin signal  112  is divided into a third signal  200  and a fourth signal  201  at node  244 . 
         [0073]    In a separate signal path, the third signal  200  is passed through a series of components for digital signal processing in the same way as the series of components for the first signal  203 . In particular, the third signal is passed through the series of components consisting of: a first High Pass Filter (HPF1)  207 , a first Equalization Filter (EQ1)  212 , a first All Pass Filter (APF1)  219 , and a first Dynamic Range Control (DRC1)  224 . The ALP1 ( 219 ) is used in the processing of the third signal  200  to optimise phase response to give better centre positioning focusing. In the digital signal processing process, the third signal  200  is processed to generate a second processed signal  228  which is connected out of phase with the first processed signal  226 . 
         [0074]    With regards to the subwoofer, the second signal  204  (0.5 of the Lin signal  111 ) and the fourth signal  201  (0.5 of the Rin signal  112 ) are passed to an adder/summation block  202  to be added to generate a subwoofer signal  205 . The subwoofer signal  205  is passed through a series of components consisting of: first Low Pass Filter (LPF1)  208 , a High Pass Filter (HPF2)  214 , a second Equalizer Filter (EQ2)  220 , and a second Dynamic RANGE Control (DRC2)  225 .  FIG. 2D  shows a gain-frequency plot  239  for the LPF1 ( 208 ). The plot  239  has a curve  242  which shows that the LPF1 ( 208  has a cut-off frequency of 1200 Hz. It is appreciated that the LPF1 ( 208 ), the HPF2 ( 214 ), the EQ2 ( 220 ) and the DRC2 ( 225 ) are used in the same way as the series of components for the first signal  203  of the Lin signal  111 . After processing, a third processed signal  230  is generated. 
         [0075]    The third processed signal  230  is divided at node  245  into a first subwoofer processed signal  246  and a second subwoofer processed signal  247 . The subwoofer signal is processed a similar way for all of the speakers in the surround system. In a front center speaker, the gain of the subwoofer signal may be adjusted or increased after a dynamic range control as shown in  FIG. 7 . 
         [0076]    The second subwoofer processed signal  247  and the first processed signal  226  are passed to an adder block  227  to be added to generate the first front right (FR) signal  123 . In this manner, the first processed signal  226  and the second subwoofer processed signal  247  can be mixed to generate the first front right (FR) signal  123  which can be an example of the aforementioned “surround sound signal”. The first subwoofer processed signal  246  and the second processed signal  228  are passed to an adder block  229  to generate the second front right (FR) signal  124 . In this manner, the first subwoofer processed signal  246  and the second processed signal  228  can be mixed to generate the second front right (FR) signal  124  which can be an example of the aforementioned “surround sound signal”. 
         [0077]      FIG. 3  show an embodiment of the front right process unit  300  of the front right speaker  104 . It is appreciated that the front right process unit  300  is the same as the front right process unit  121  of  FIG. 2A  except that the Rin signal  112  is divided at node  343 , and later node  344  into three signals, namely, a first signal  306 , a second signal  307  and a third signal  304 . The three signals are processed individually in the same way as the first signal  203  and the third signal  200  of the front right process unit  121  of  FIG. 2A . The first signal  306  and the second signal  307  of the Rin signal  112  are processed to generate a first processed signal  334  and a second processed signal  335 . The Lin signal  111  is divided at node  345  into a fourth signal  301  and a fifth signal  302 . The fourth signal  301  and the fifth signal  302  are processed individually in the same way as the third signal  200  and the fourth signal  201  of the front right process unit  121  of  FIG. 2A . In this regard, where appropriate, the foregoing discussed with regard to  FIG. 2A  analogously applies. 
       Front Left Process Unit 
       [0078]      FIGS. 4A to 4D  illustrate a front left (FL) process unit  400  of the front right (FL) speaker  102  according to an embodiment. 
         [0079]      FIG. 4A  shows a block diagram of the components of a front left (FL) process unit  400  (Option ‘A’) for generating a first front left (FL) signal  115  and a second front left (FL) signal  116 . The FL process unit  400  is configured to receive the Lin and Rin signals  111 ,  112  wirelessly, and process the L and R signals separately and independently, and eventually produce the output which is the surround sound signal comprising first front left (FL) signal  115  and a second front left (FL) signal  116 . The Lin signal  111  is divided or split into a first signal  401  and a second signal  434  at node  432 . The Rin signal  112  is divided into a third signal  402  and a fourth signal  403  at node  433 . 
         [0080]    The first signal  401  is passed through a series of components for digital signal processing consisting of: a first High Pass Filter (HPF1)  406 , an Equalizer Filter (EQ1)  412 , a first All Pass Filter (ALP1)  418 , and a first Dynamic Range Control (DRC1)  424 . The third signal  402  of the Rin signal  112  is passed through a series of components for digital signal processing consisting of: a first High Pass Filter (HPF1)  407 , an Equalizer Filter (EQ1)  413 , a second Low Pass Filter (LPF2)  419 , and a Dynamic Range Control (DRC1)  424 . 
         [0081]    The Lin and Rin signals  111 ,  112  are processed in the same way as the Lin and Rin signals in the FR process unit ( 121 ,  300 ) to generate a first front left (FL) signal  115  and a second front left (FL) signal  116  except that in the FL process unit  400 ; there is a switch over in components, i.e. the first All Pass Filter (ALP1)  418  and the second Low Pass Filter (LPF2)  419 . This means that first signal  401  of the front left (FL) process unit  400  will be passed to the ALP1 ( 418 ) instead of the LFP2 ( 419 ) when front left (FL) process unit  400  is activated. When the front left process unit  400  is activated, the first signal  401  of the Lin signal  111  is driving the ALP1 ( 418 ). The ALP1 ( 418 ) is used to optimise phase response to give better centre positioning focusing. 
         [0082]    With regards to the subwoofer, the second signal  434  (0.5 of the Lin signal  111 ) and the fourth signal  403  (0.5 of the Rin signal  112 ) are passed to an adder/summation block  404  to be added to generate a subwoofer signal  405 . The subwoofer signal  405  is passed through a series of components consisting of: first Low Pass Filter (LPF1)  408 , a High Pass Filter (HPF2)  414 , a second Equalizer Filter (EQ2)  420 , and a second Dynamic Range Control (DRC2)  425 .  FIG. 4D  shows a gain-frequency plot  239  for the LPF1 ( 408 ). The plot  239  has a curve  443  which shows that the LPF1 ( 408 ) has a cut-off frequency of 1200 Hz. It is appreciated that the LPF1 ( 408 ), the HPF2 ( 414 ), the EQ2 ( 420 ) and the DRC2 ( 425 ) are used in the same way as the series of components for the subwoofer signal  205  of the FR processing unit  121  of  FIG. 2A . The subwoofer signal is processed in a similar way for all of the speakers in the surround system. 
         [0083]    In this regard, where appropriate, the foregoing discussed with regard to  FIG. 2A  analogously applies. 
         [0084]      FIG. 4B  show a gain-frequency plot  432  for the HPF1 ( 406 ) of the FL process unit  400 . The plot  432  shows a curve  435  which indicates that the cut-off frequency of the HPF1 ( 406 ) is 200 Hz. 
         [0085]      FIG. 4C  show a gain-frequency plot  436  for the LPF2 ( 419 ) of the FL process unit  400 . The plot  436  shows a curve  439  which indicates that the cut-off frequency of the LPF2 ( 419 ) is 1200 Hz. 
         [0086]      FIG. 5  show an embodiment of a front left (FL) process unit  500  of the front left speaker  102 . It is appreciated that the front left process unit  500  is the same as the front left process unit  400  of  FIG. 4A  except that the Lin signal  111  is divided at node  541  into first signal  501  and second signal  502 , and later at node  542  into two signals, namely, a third signal  545  and a fourth signal  546 . The three signals ( 501 ,  545 ,  546 ) are processed individually in the same way as the signals of the front left process unit  300  of  FIG. 4A . In this regard, where appropriate, the foregoing discussed with regard to  FIG. 4A  analogously applies. 
       Front Center Process Unit 
       [0087]      FIG. 6A  show an embodiment of a front center (FC) process unit  600  of the front center speaker  103 . Similar to the processing units described above, the FC process unit  600  is configured to receive the Lin and Rin signals  111 ,  112  wirelessly, and process the L and R signals separately and independently, and eventually produce the output which is the surround sound signal comprising first front center (FC) signal  641  and a second front center (FC) signal  642 . 
         [0088]    The Lin signal  111  is divided into a first signal  649  and a second signal  602  (0.5 of Lin signal  111 ) at node  643 . The first signal  649  is further divided into a third signal  623  and a fourth signal  601  at node  644 . The Rin signal  112  is divided into a fifth signal  603  and a sixth signal  604  (0.5 of Rin signal  112 ) at node  645 . 
         [0089]    The second signal  602  (0.5 of Lin signal  111 ) and sixth signal  604  (0.5 of Rin signal  112 ) are summed up at an adder block  607  to generate a subwoofer signal  608 . The subwoofer signal  608  is passed through a series of components for digital signal processing consisting of: a first Low Pass Filter (LPF1)  613 , a second High Pass Filter (HPF2)  614 , a second Equalizer Filter (EQ2)  615 , a second Dynamic Range Control (DRC2)  617  to generate a processed signal  650 . The EQ2 ( 615 ) has a 12 dB boost at 180 Hz. The processed signal  650  is further divided into a first subwoofer signal  618  and a second subwoofer signal  619  at node  648 . 
         [0090]    In a separate signal path, the fifth signal  603  is further divided at node  644  into a seventh signal  605  and an eight signal  608 . The seventh signal  605  and the fourth signal  601  are passed to an accumulator block  609  to generate a accumulated signal  645 . The signal  645  is passed through a series of components consisting of: a High Pass Filter (HPF1)  626 , an Equalizer Filter (EQ3)  611  and an All Pass Filter (ALP2)  612 .  FIG. 6B  shows a gain-frequency plot  643  of the HPF1 whereby a curve  646  illustrates that the HPF1 has a cut off frequency of 180 Hz. The EQ3 ( 611 ) is catered for the driver frequency response and the ALP2 ( 612 ) is to optimize the phase difference so as to provide better focusing. After being processed by the series of components, the processed signal  620  is divided at node  647  to generate a left +0.5 input signal  621  and a right +0.5 input signal  622 . 
         [0091]    The left +0.5× input signal  621  and the right −0.5× input signal  622  are mixed with a +0.75× left signal  623  and a +0.75× right input signal  606  at an accumulator block  624 , and at an accumulator block  630  respectively. With the mixing completed, a processed signal  625  is generated at the left input. The signal  625  is passed through a series of components consisting of a High Pass Filter (HPF1)  626  and an Equalizer Filter (EQ4)  628  and a Dynamic Range Control (DRC1)  636  to generate a processed signal  637 . In a separate signal path at the right input, a processed signal  631  is generated after mixing and is processed in the same way as the processed signal  625 . The signal  631  is passed through a series of components consisting of a High Pass Filter (HPF1)  632  and an Equalizer Filter (EQ4)  634  and a Dynamic Range Control (DRC1)  636  to generate a processed signal  638 . The EQ 4 ( 628 ,  634 ) enhances the mid frequency to give a better defined vocal scene. 
         [0092]    The processed signal  637  and the second subwoofer signal  619  is passed to an adder block  640  to generate a first Front Center (FC) signal  641 . The processed signal  638  and the first subwoofer signal  618  is passed to an adder block  639  to generate a second Front Center (FC) signal  642 . 
         [0093]      FIG. 7  shows an embodiment of the Front Center (FC) Process Unit (Option B)  700 . The FC process unit  700  processes the Lin signal  111  and the Rin signal  112  in a similar way to the FC process unit  600  of  FIG. 6A  except that there is further mixing after a dynamic range control of the respective signals and the subwoofer signal is also mixed after digital signal processing. 
       Side Right Process Unit 
       [0094]      FIG. 8  shows a block diagram of the components of a side right (SR) process unit  800  of the side right (SR) speaker  106  according to an embodiment. 
         [0095]    The side right (SR) process unit  800  generates the output surround sound signal comprising a first side right (SR) signal  841  and a second side right (SR) signal  842 . The SR process unit  800  is configured to receive the Lin and Rin signals  111 ,  112  wirelessly, and process the L and R signals separately and independently, and eventually produce the output which is the surround sound signal comprising first side right (SR) signal  841  and a second side right (SR) signal  842 . The Lin signal  111  is divided or split into a first signal  801  and a second signal  802  (+2L−R) at node  843 . The Rin signal  112  is divided into a third signal  803  and a fourth signal  804  at node  844 . 
         [0096]    The second signal  802  and the fourth signal  804  is added at an adder block  805  to generate a fifth signal  810 . In particular, the fifth signal  810  is further divided at node  846  into a sixth signal  811  and a seventh signal  812 . The sixth signal  811  is passed though a series of components consisting of: a first High Pass Filter (HPF1)  814 , a sixth Equalization Filter (EQ6)  820 , a first All Pass Filter (APF1)  826 , and a first Dynamic Range Control (DRC1)  832 . The amplitude of low frequency components of the signal  811  are attenuated by the HPF1 ( 814 ). After the low frequency components are filtered, the filtered signal  817  is then directed to the EQ6 ( 820 ) for adjusting of the high frequency components of the filtered signal  817  to generate an equalized signal  823 . The equalized signal  823  is passed to the ALP1 ( 826 ) to generate a second filtered signal  829 . The ALP1 ( 826 ) is used in the processing of the signal  823  to optimise phase response to give better centre positioning focusing. The second filtered signal  829  is passed to the DRC1 ( 832 ) to apply an appropriate gain so as to generate a first processed signal  834  (+1). 
         [0097]    In a separate signal path, the third signal  803  is passed through a series of components for digital signal processing in the same way as the series of components for the first signal  801 . In particular, the third signal  803  and the signal  801  are passed to an adder block  806  to generate a signal  807 . The signal  807  is divided at node  845  into a first signal  808  and a second signal  809 . The first signal  808  is passed through the series of components consisting of: a first High Pass Filter (HPF1)  815 , a first Equalization Filter (EQ6)  821 , a Low Pass Filter (LPF2)  827 , and a first Dynamic Range Control (DRC1)  832  to generate a second processed signal  835  which is out of phase with the first processed signal  834 . 
         [0098]    With regards to the subwoofer, the second signal  809  (0.5 of the signal  807 ) and the signal  812  (0.5 of the signal  810 ) are passed to an adder/summation block  847  to be added to generate a signal  813 . The signal  813  is passed through a series of components consisting of: first Low Pass Filter (LPF1)  816 , a High Pass Filter (HPF2)  822 , a second Equalizer Filter (EQ2)  828 , and a second Dynamic Range Control (DRC2)  833 . After processing, a subwoofer signal  837  is generated and is divided at node  850  into a first subwoofer processed signal  837  and a second subwoofer processed signal  838 . 
         [0099]    The second subwoofer processed signal  838  and the first processed signal  834  are passed to an adder block  839  to generate the first side right (SR) signal  841 . The first subwoofer processed signal  837  and the second processed signal  835  are passed to an adder block  840  to generate the second side right (SR) signal  842 . 
       Side Left, Rear Right and Rear Left Process Units 
       [0100]      FIGS. 9 ,  10  and  11  illustrate a side left (SL)  900 , rear right (RR)  1000  and rear left (RL)  1100  process units respectively. The signal processing in each process unit is similar to that description in  FIG. 8  for the side right (SR) process unit  800 . 
         [0101]    In an alternative embodiment of the invention, the speaker is capable of having placement information associated with a placement of the speaker within a surround sound environment. The speaker is then capable of producing a placement specific output signal associated with the placement of the speaker within the surround sound environment. The speaker of this embodiment will have a processing unit capable of carrying out the processing of audio signals described above. However, in addition to the above description, the processing unit is further configured to process the received audio signal including the L signal component and the R signal component in association with the placement information to produce the placement specific output signal. This requires the placement information to be received by the processing unit from an external source based on a unique identifier associated with the receiver. The placement information may include a relative placement of the speaker compared to one or more additional speakers placed within the surround sound environment. 
         [0102]    Appreciably, where similar, the foregoing discussed with regard to  FIG. 2A  and/or  FIG. 4A  applies analogously to  FIG. 5  to  FIG. 11  as appropriate. 
         [0103]    Whilst there has been described in the foregoing description preferred embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations or modifications in details of design or construction may be made without departing from the present invention.