Sound signal playback machine and method thereof

Abstract

In a sound signal playback machine and method thereof, predetermined high frequency components are extracted from sound signals S L to S C of a main channel by high frequency pass filters 21 to 25, and these high frequency components are respectively played back by speakers. At the same time, predetermined low frequency components are extracted from sound signals S L to S C of the main channel by low frequency pass filters. These low frequency components and sound signal S LFE exclusively used for the low frequency band are added to each other, and the thus obtained addition signal is played back by the speaker 66. In this case, the degree of the low frequency pass filters is set higher than the degree of the high frequency pass filters, and the high frequency component is delayed.

1. A sound signal playback machine comprising:
 a high frequency pass filter for extracting a predetermined high frequency component from a sound signal in a main channel; 
 a first speaker for playing back the high frequency component extracted by the high frequency pass filter; 
 a low frequency pass filter for extracting a predetermined low frequency component from the sound signal in the main channel; 
 a signal adder for outputting an addition signal in which the low frequency component extracted by the low frequency pass filter is added to a sound signal in a channel exclusively used for a low frequency band; and 
 a second speaker for playing back the addition signal outputted from the signal adder, 
 wherein the degree of the low frequency pass filter is set higher than that of the high frequency pass filter, and 
 wherein the sound signal playback machine further comprising a phase matching unit for matching the phase of the high frequency component extracted by the high frequency pass filter with the phase of the low frequency component extracted by the low frequency pass filter. 
 
     
     
       2. The sound signal playback machine according to  claim 1 , wherein the phase matching unit is a delay circuit for delaying the high frequency component extracted by the high frequency pass filter. 
     
     
       3. The sound signal playback machine according to  claim 2 , wherein delay time T1 (sec) of the delay circuit is set at a value calculated by the equation of
   T1=(φ1−φ2+π·n)/(2π·Fc)
 
 (n=. . . −2, −1, 0, 1, 2 . . .) 
 where φ1 (rad) is a phase angle at a cut-off frequency Fc (Hz) of the high frequency pass filter, and φ2 (rad) is a phase angle of the low frequency pass filter. 
 
     
     
       4. The sound signal playback machine according to  claim 1 , wherein the phase matching unit is to set the first speaker by moving it in a direction so that the first speaker can be separated from a listener. 
     
     
       5. The sound signal playback machine according to  claim 1 , wherein the phase matching unit is to set the second speaker by moving it in a direction so that the second speaker can be approached to a listener, and the phase matching means is also a delay circuit for delaying the addition signal outputted from the signal adder. 
     
     
       6. The sound signal playback machine according to  claim 1 , further comprising an auxiliary phase matching unit adapted to match the phase of the low frequency component extracted by the low frequency pass filter with the phase of the sound signal in the channel exclusively used for the low frequency band. 
     
     
       7. The sound signal playback machine according to  claim 6 , wherein the auxiliary phase matching unit is a delay circuit for delaying the sound signal in the channel exclusively used for the low frequency band. 
     
     
       8. The sound signal playback machine according to  claim 7 , wherein delay time T2 (sec) of the delay circuit is set at a value calculated by the equation of
   T2=(φ1+π·n)/(2π·Fc)
   (n=. . . −2, −1, 0, 1, 2 . . .)   where φ1 (rad) is a phase angle at a cut-off frequency Fc (Hz) of the high frequency pass filter.   
     
     
       9. The sound signal playback machine according to  claim 1 , further comprising a phase inversion circuit for inverting a phase of the low frequency component extracted by the low frequency pass filter when a difference between the phase of the low frequency component extracted by the low frequency pass filter and the phase of the sound signal in the channel exclusively used for the low frequency is n (rad). 
     
     
       10. A sound signal playback method comprising the steps of:
 extracting a predetermined high frequency component from a sound signal in a main channel by a high frequency pass filter; 
 playing back the high frequency component, which has been extracted by the high frequency pass filter, by a first speaker; 
 extracting a predetermined low frequency component from the sound signal in the main channel by a low frequency pass filter; 
 adding the low frequency component extracted by the low frequency pass filter to a sound signal in the channel exclusively used for the low frequency by a signal adder and outputting an addition signal; and 
 playing back the addition signal, which has been outputted from the signal adder, by a second speaker, 
 wherein the degree of the low frequency pass filter is set higher than that of the high frequency pass filter, and 
 wherein the phase of the high frequency component extracted by the high frequency pass filter and the phase of the low frequency component extracted by the low frequency pass filter are matched with each other. 
 
     
     
       11. The sound signal playback method according to  claim 10 , wherein the phase of the high frequency component extracted by the high frequency pass filter and the phase of the low frequency component extracted by the low frequency pass filter are matched with each other when the high frequency component extracted by high frequency pass filter is delayed by the delay circuit. 
     
     
       12. The sound signal playback method according to  claim 11 , wherein delay time T1 (sec) of the delay circuit is set at a value calculated by the equation of
   T1=(φ1−φ2+π·n)/(2π·Fc)
 
 (n=. . . −2, −1, 0, 1, 2 . . . )
 where φ1 (rad) is a phase angle at a cut-off frequency Fc (Hz) of the high frequency pass filter, and φ2 (rad) is a phase angle of the low frequency pass filter. 
 
 
     
     
       13. The sound signal playback method according to  claim 10 , wherein the phase of the high frequency component extracted by the high frequency pass filter and the phase of the low frequency component extracted by the low frequency pass filter are matched with each other when the first speaker is arranged by moving so that it can be separated from a listener. 
     
     
       14. The sound signal playback method according to  claim 10 , wherein the phase of the high frequency component extracted by the high frequency pass filter and the phase of the low frequency component extracted by the low frequency pass filter are matched with each other when the second speaker is arranged by moving so that it can be separated from a listener and the addition signal outputted from the signal adder is delayed by the delay circuit. 
     
     
       15. The sound signal playback method according to  claim 10 , wherein the phase of the low frequency component extracted by the low frequency pass filter and the phase of the sound signal in the channel exclusively used for the low frequency band are matched with each other. 
     
     
       16. The sound signal playback method according to  claim 15 , wherein the phase of the low frequency component extracted by the low frequency pass filter and the phase of the sound signal in the channel exclusively used for the low frequency band are matched with each other by delaying the sound signal in the channel exclusively used for the low frequency band by the delay circuit. 
     
     
       17. The sound signal playback method according to  claim 16 , wherein delay time T2 (sec) of the delay circuit is set at a value calculated by the equation of
   T2=(φ1+π·n)/(2π·Fc)
   (n=. . . −2, −1, 0, 1, 2 . . . )   
       where φ1 (rad) is a phase angle at a cut-off frequency Fc (Hz) of the high frequency pass filter. 
     
     
       18. The sound signal playback method according to  claim 10 , wherein the phase of the low frequency component extracted by the low frequency pass filter is inverted by the phase inversion circuit when a difference between the phase of the low frequency component extracted by the low frequency pass filter and the phase of the sound signal in the channel exclusively used for the low frequency is π (rad). 
     
     
       19. A sound signal playback machine comprising:
 a high frequency pass filter for extracting a high frequency component from a sound signal in a main channel;   a first speaker for playing back the high frequency component extracted by the high frequency pass filter;   a low frequency pass filter for extracting a low frequency component from the sound signal in the main channel;   an adder that adds the low frequency component extracted by the low frequency pass filter to a sound signal in a channel exclusively used for a low frequency band to produce an addition signal; and   a second speaker for playing back the addition signal,   wherein a degree of the low frequency pass filter is set higher than a degree of the high frequency pass filter; and   wherein at least one of a phase of the high frequency component and a phase of the low frequency component is adjusted to match the phase of the high frequency component with the phase of the low frequency component.    
     
     
       20. The sound signal playback machine according to claim 19, wherein a group delay characteristic is obtained when a signal that includes the low frequency component is synthesized with a signal that includes the high frequency component, and
 wherein the phase of the high frequency component is matched with the phase of the low frequency component such that the group delay characteristic is substantially flat.    
     
     
       21. The sound signal playback machine according to claim 19, further comprising a delay circuit that delays the high frequency component extracted by the high frequency pass filter to match the phase of the high frequency component with the phase of the low frequency component.  
     
     
       22. The sound signal playback machine according to claim 21, wherein a delay time T1 (sec) of the delay circuit is set at a value calculated by the equation of
   T1=(φ1−φ2+π·n)/(2π·Fc)
   (n=. . . −2, −1, 0, 1, 2 . . . )
 where φ1 (rad) is a phase angle at a cut-off frequency Fc (Hz) of the high frequency pass filter, and φ2 (rad) is a phase angle of the low frequency pass filter.  
   
     
     
       23. The sound signal playback machine according to claim 19, further comprising an auxiliary phase matching circuit that matches the phase of the low frequency component extracted by the low frequency pass filter with a phase of the sound signal in the channel exclusively used for the low frequency band.  
     
     
       24. The sound signal playback machine according to claim 23, wherein the auxiliary phase matching circuit comprises a delay circuit that delays the sound signal in the channel exclusively used for the low frequency band so that the phase of the sound signal in the channel exclusively used for the low frequency band matches the phase of the low frequency component extracted by the low frequency pass filter.  
     
     
       25. The sound signal playback machine according to claim 19, further comprising a phase inversion circuit that inverts a phase of the low frequency component extracted by the low frequency pass filter when a difference between the phase of the low frequency component and the phase of the sound signal in the channel exclusively used for the low frequency is π (rad).  
     
     
       26. The sound signal playback machine according to claim 19, wherein the phase of the high frequency component is matched with the phase of the low frequency component by moving the first speaker away from a predetermined position of a listener by a particular distance.  
     
     
       27. The sound signal playback machine according to claim 26, wherein the particular distance corresponds to a delay time T1 (sec), which is set at a value calculated by the equation of
   T1=(φ1−φ2+π·m)/(2π·Fc)
   (n=. . . −2, −1, 0, 1, 2 . . . )   where φ1 (rad) is a phase angle at a cut-off frequency Fc (Hz) of the high frequency pass filter, and φ2 (rad) is a phase angle of the low frequency pass filter.    
     
     
       28. The sound signal playback machine according to claim 19, wherein the phase of the high frequency component is matched with the phase of the low frequency component by moving the second speaker towards a predetermined position of a listener by a particular distance.  
     
     
       29. The sound signal playback machine according to claim 28, further comprising a delay circuit,
 wherein the phase of the high frequency component is matched with the phase of the low frequency component by (1) moving the second speaker towards the predetermined position by the particular distance and (2) delaying the addition signal played back by the second speaker.    
     
     
       30. The sound signal playback machine according to claim 29, wherein a difference between a delay time of the delay circuit and a delay time corresponding to the particular distance corresponds to a delay time T1 (sec), which is set at a value calculated by the equation of
   T1=(φ1−φ2+π·n)/(2π·Fc)
   (n=. . . −2, −1, 0, 1, 2 . . . )
 where φ1 (rad) is a phase angle at a cut-off frequency Fc (Hz) of the high frequency pass filter, and φ2 (rad) is a phase angle of the low frequency pass filter.  
   
     
     
       31. The sound signal playback machine according to claim 19, further comprising:
 a first delay circuit that delays the high frequency component based on a distance between the first speaker and a predetermined position of a listener; and   a second delay circuit that delays the high frequency component to match the phase of the high frequency component with the phase of the low frequency component.    
     
     
       32. The sound signal playback machine according to claim 31, further comprising:
 a third delay circuit that delays the addition signal based on a distance between the second speaker and the predetermined position of the listener.    
     
     
       33. A sound signal processing machine comprising:
 a high frequency pass filter for extracting a high frequency component from a sound signal in a main channel;   a low frequency pass filter for extracting a low frequency component from the sound signal in the main channel;   wherein a degree of the low frequency pass filter is set higher than a degree of the high frequency pass filter, and   wherein at least one of a phase of the high frequency component and a phase of the low frequency component is adjusted to match the phase of the high frequency component with the phase of the low frequency component.    
     
     
       34. The sound signal playback machine according to claim 33, wherein a group delay characteristic is obtained when a signal that includes the low frequency component is synthesized with a signal that includes the high frequency component, and
 wherein the phase of the high frequency component is matched with the phase of the low frequency component such that the group delay characteristic is substantially flat.    
     
     
       35. The sound signal playback machine according to claim 33, further comprising a delay circuit that delays the high frequency component extracted by the high frequency pass filter to match the phase of the high frequency component with the phase of the low frequency component.  
     
     
       36. The sound signal processing machine according to claim 33, further comprising:
 a signal adder that adds the low frequency component extracted by the low frequency pass filter to a sound signal in a channel exclusively used for a low frequency band.    
     
     
       37. The sound signal playback machine according to claim 35, wherein a delay time T1 (sec) of the delay circuit is set at a value calculated by the equation of
   T1=(φ1−φ2+π·n)/(2π·Fc)
   (n=. . . −2, −1, 0, 1, 2 . . . )   
       where φ1 (rad) is a phase angle at a cut-off frequency Fc (Hz) of the high frequency pass filter, and φ2 (rad) is a phase angle of the low frequency pass filter.  
     
     
       38. The sound signal playback machine according to claim 36, further comprising an auxiliary phase matching circuit that matches the phase of the low frequency component extracted by the low frequency pass filter with a phase of the sound signal in the channel exclusively used for the low frequency band.  
     
     
       39. The sound signal playback machine according to claim 38, wherein the auxiliary phase matching circuit comprises a delay circuit that delays the sound signal in the channel exclusively used for the low frequency band so that the phase of the sound signal in the channel exclusively used for the low frequency band matches the phase of the low frequency component extracted by the low frequency pass filter.  
     
     
       40. The sound signal playback machine according to claim 36, further comprising a phase inversion circuit that inverts a phase of the low frequency component extracted by the low frequency pass filter when a difference between the phase of the low frequency component and the phase of the sound signal in the channel exclusively used for the low frequency is π (rad).