Infra bass

Abstract

To improve the aural sensation from an input signal of an audio reproduction system a bandwidth extension device can be used. The bandwidth extension device includes a first and a second signal path and an analyzer for selecting the created signal which fits most for the current input signal.

1 . A bandwidth extension device comprising: 
 an input for receiving an input signal;    at least a first signal path and a second signal path coupled to the input, each of said first and second signal paths having filter means for filtering the input signal and creating means for creating an adapted signal with a lower frequency part than the input signal, said first and second signal paths supplying a first and a second adapted signal;    analyze means for analyzing the first and the second adapted signals for correspondence with the input signal; and    means for selecting the first or the second adapted signal compared to correspond most with the input signal.    
     
     
         2 . The bandwidth extension device as claimed in  claim 1 , characterized in that the selecting means comprises switching means for switching between the first and the second signal paths.  
     
     
         3 . The bandwidth extension device as claimed in  claim 1 , characterized in that the analyze means controls each of the creating means.  
     
     
         4 . The bandwidth extension device as claimed in  claim 1 , characterized in that the selecting means comprises mixers.  
     
     
         5 . An audio reproduction system comprising a bandwidth extension device as claimed in  claim 1 .  
     
     
         6 . The audio reproduction system as claimed in  claim 5 , characterized in that the audio reproduction system comprises time delay means to compensate for any delay in the bandwidth extension device.  
     
     
         7 . The bandwidth extension device as claimed in  claim 1 , characterized in that the first adapted signal comprises a stream of harmonics as if a first frequency component in the filtered input signal in the first signal path was a second harmonic, and the second adapted signal comprises a stream of harmonics as if a first frequency component in the filtered input signal in the second signal path was a third harmonic.  
     
     
         8 . The bandwidth extension device as claimed in  claim 7 , characterized in that the filter means of the first signal path comprises a band-pass filter for filtering in a frequency range of 300-600 Hz., and the filter means of the second signal path comprises a band-pass filter for filtering in a frequency range of 300-400 Hz.  
     
     
         9 . The bandwidth extension device as claimed in  claim 7 , characterized in that the analyze means selects the harmonic streams in the frequency domain.  
     
     
         10 . A bandwidth extension device comprising: 
 an input for receiving an input signal;    at least a first signal path and a second signal path coupled to the input, each of said first and second signal paths having filter means for filtering the input signal and creating means for creating an adapted signal with a lower frequency part than the input signal, said first and second signal paths supplying a first and a second adapted signal;    analyze means for analyzing the first and second adapted signals for correspondence with the input signal; and    means for selecting the first or the second adapted signal corresponding most with the input signal,    characterized in that the first signal path comprises a first mixer and the second signal path comprises a second mixer, the analyze means being adapted to supply a first control signal to the first mixer and a second control signal to the second mixer, and in that the means for selecting the first or the second adapted signal is adapted for summing outputs of the first and second mixers.