Pseudo multi-channel stereo play-back apparatus

Abstract

Compressed audio data for 5.1 channels stored in the DVD-ROM 11 A is read by the AC-3 decoder 12 of a pseudo multi-channel stereo play-back apparatus and, after expansion, stored temporarily in a buffer 13 , channel by channel. Among stored audio data stored in the buffer 13 , audio data for left and right channels and for a front center channel are then subjected to the phase transformation. Audio data for left and right front channels are mixed with the phase transformed audio data by first and second mixing circuits 21 and 22 and mixed audio data are converted into analog audio signals by first and second D/A converters. The apparatus is capable of pseudo reproduction of the multi-channel audio signals stored in a recording medium such as a DVD-ROM by two channel play-back with an excellent sound effect which is not obtainable by usual two-channel play-back systems.

1 . An apparatus comprising:
 a memory which stores first digital audio data for being reproduced at a first point which is behind a listener and second digital audio data for being reproduced at a second point which is in front of said listener, said first and second digital audio data capable of being listened to by said listener with a first surround effect;   a processor which processes a first digital audio signal corresponding to said first digital audio data to be reproduced at said second point;   a mixer which mixes said first digital audio signal having been processed by said processor, and a second digital audio signal corresponding to said second digital audio data and having not been processed by said processor; and   a D/A converter which converts an output of said mixer into an analog audio signal for being reproduced at said second point, which is capable of being listened to by said listener with a second surround effect which is substantially the same as said first surround effect.   
   
   
       2 . An apparatus of  claim 1 , wherein, based on at least one of predetermined functions, said mixer mixes said first digital audio signal having been processed by said processor, and said second digital audio signal having not been processed by said processor. 
   
   
       3 . An apparatus of  claim 2 , further comprising a speaker located at said second point and which reproduces said analog audio signal. 
   
   
       4 . An apparatus comprising:
 a memory which stores first digital audio data for being reproduced at a first point which is behind a listener and second digital audio data for being reproduced at a second point which is in front of said listener, said first and second digital audio data capable of being listened to by said listener with a first surround effect;   a processing unit which processes a first digital audio signal corresponding to said first digital audio data to be reproduced at said second point, and which mixes said processed first digital audio signal, and a non-processed second digital audio signal corresponding to said second digital audio data; and   a D/A converter which converts an output of said processing unit into an analog audio signal for being reproduced at said second point which is capable of being listened to by said listener with a second surround effect which is substantially the same as said first surround effect.   
   
   
       5 . An apparatus of  claim 4 , wherein, based on at least one of predetermined functions, said processing unit mixes said processed first digital audio signal and said non-processed second digital audio signal. 
   
   
       6 . An apparatus of  claim 5 , further comprising a speaker located at said second point and which reproduces said analog audio signal. 
   
   
       7 . An apparatus of  claim 1 , wherein said first digital audio signal is processed by said processor performing phase control on said first digital audio signal. 
   
   
       8 . An apparatus of  claim 4 , wherein said first digital audio signal is processed by said processing unit performing phase control on said first digital audio signal.