Method and signal processing device for converting stereo signals for headphone listening
First Claim
1. A method for converting two-channel stereo format left (L) and right (R) channel input signals (Lin,Rin) into left and right channel output signals (Lout,Rout), in which methodleft direct path (Ld) and left cross-talk path (LX) signals are formed from the left input signal (Lin), and correspondingly right direct path (Rd) and right cross-talk path (RX) signals are formed from the right input signal (Rn), and the left output signal (Lout) is formed by combining said left direct-path (Ld) and said right cross-talk path (Rx) signals, and correspondingly, the right output signal (Rout) is formed by combining said right direct-path (Rd) and said left cross-talk path (Lx) signals, which said left and right channel output signals (Lout,Rout) thereby become suitable for headphone listening, characterized in thatthe direct path signals (Ld,Rd) each are formed using filtering (1,3) associated with first frequency dependent gain (Gd), the cross-talk path signals (Lx,Rx) each are formed using filtering (2,4) associated with second frequency dependent gain (Gx) and by adding interaural time difference (ITD) (5,6), said first and second frequency dependent gains (Gd, Gx) are given a common substantially constant reference value below a first frequency limit (flow), said first frequency dependent gain (Gd) is given a substantially constant value significantly greater than said reference value, and said second frequency dependent gain (Gx) is given a substantially constant value significantly less than said reference value above a second frequency limit (fhigh), where said second frequency limit (fhigh) is greater than said first frequency limit (flow), and said interaural time difference (ITD) is given a frequency independent constant value or alternatively a frequency dependent value.
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Abstract
The invention relates to a method for converting signals in two-channel stereo format to become suitable to be played back using headphones. The invention also relates to a signal processing device for carrying out said method. According to the invention left direct path (Ld) and left cross-talk path (LX) signals are formed from the left input signal (Lin), and correspondingly right direct path (Rd) and right cross-talk path (RX) signals are formed from the right input signal (Rin), and further the left output signal (Lout) is formed by combining said left direct-path (Ld) and said right cross-talk path (Rx) signals, and correspondingly, the right output signal (Rout) is formed by combining said right direct-path (Rd) and said left cross-talk path (Lx) signals. The direct path signals (Ld,Rd) each are formed using filtering (1,3) associated with first frequency dependent gain (Gd) and the cross-talk path signals (Lx,Rx) each are formed using filtering (2,4) associated with second frequency dependent gain (Gx) and by adding interaural time difference (ITD) (5,6).
42 Citations
16 Claims
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1. A method for converting two-channel stereo format left (L) and right (R) channel input signals (Lin,Rin) into left and right channel output signals (Lout,Rout), in which method
left direct path (Ld) and left cross-talk path (LX) signals are formed from the left input signal (Lin), and correspondingly right direct path (Rd) and right cross-talk path (RX) signals are formed from the right input signal (Rn), and the left output signal (Lout) is formed by combining said left direct-path (Ld) and said right cross-talk path (Rx) signals, and correspondingly, the right output signal (Rout) is formed by combining said right direct-path (Rd) and said left cross-talk path (Lx) signals, which said left and right channel output signals (Lout,Rout) thereby become suitable for headphone listening, characterized in that the direct path signals (Ld,Rd) each are formed using filtering (1,3) associated with first frequency dependent gain (Gd), the cross-talk path signals (Lx,Rx) each are formed using filtering (2,4) associated with second frequency dependent gain (Gx) and by adding interaural time difference (ITD) (5,6), said first and second frequency dependent gains (Gd, Gx) are given a common substantially constant reference value below a first frequency limit (flow), said first frequency dependent gain (Gd) is given a substantially constant value significantly greater than said reference value, and said second frequency dependent gain (Gx) is given a substantially constant value significantly less than said reference value above a second frequency limit (fhigh), where said second frequency limit (fhigh) is greater than said first frequency limit (flow), and said interaural time difference (ITD) is given a frequency independent constant value or alternatively a frequency dependent value.
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7. A signal processing device (BSWN) for converting two-channel stereo format left (L) and right (R) channel input signals (Lin,Rin) into left and right channel output signals (Lout,Rout) suitable for headphone listening, characterized in that the signal processing device (BSWN) comprises at least
first filtering means (1) associated with first frequency dependent gain (Gd) to form left direct path signal (Ld) from said left input signal (Lin), second filtering means (2) associated with second frequency dependent gain (Gx) in serial with first delay adding means (5) associated with interaural time difference (ITD) to form left cross-talk path signal (Lx) from said left input signal (Lin), associated with interaural time difference (ITD) to form left cross-talk path signal (Lx) from said left input signal (Lin), third filtering means (3) associated with first frequency dependent gain (Gd) to form right direct path signal (Rx) from said right input signal (Rin), fourth filtering means (4) associated with second frequency dependent gain (Gx) in serial with second delay adding means (6) associated with interaural time difference (ITD) to form right cross-talk path signal (Rx) from said right input signal (Rin), first combining means (7) to form the left output signal (Lout) by combining said left direct-path (Ld) and said right cross-talk path (Rx) signals, and correspondingly, second combining means (8) to form the right output signal (Rout) by combining said right direct-path (Rd) and said left cross-talk path (Lx) signals, and said first and second frequency dependent gains (Gd,Gx) having a common constant reference value below a first frequency limit (flow), said first frequency dependent gain (Gd) having a substantially constant value significantly greater than said reference value, and said second frequency dependent gain (Gx) having a substantially constant value significantly less than said reference value above a second frequency limit (fhigh), where said second frequency limit (fhigh) is greater than said first frequency limit (flow), and said interaural time difference (ITD) is having a frequency independent constant value or alternatively a frequency dependent value.
Specification