CROSS-OVER FREQUENCY SELECTION AND OPTIMIZATION OF RESPONSE AROUND CROSS-OVER
First Claim
1. A signal processor configured to select a cross-over frequency to attenuate a spectral notch in a cross-over region, the signal processor comprising a configuration to:
- measure a full-range subwoofer and satellite speaker response in at least one position in a room, the full range subwoofer and satellite speaker response characterized by;
select a cross-over region from the full range subwoofer and satellite speaker response;
select a set of candidate cross-over frequencies and corresponding bass-management filters for the subwoofer and the satellite speaker;
apply corresponding bass-management filters to the full-range subwoofer and satellite speaker response to obtain bass managed subwoofer and satellite speaker responses;
level match the bass managed subwoofer and satellite speaker responses to obtain leveled subwoofer and satellite speaker responses;
sum the leveled subwoofer and satellite speaker responses to obtain a net bass-managed subwoofer and satellite speaker response;
compute an objective function measure using the net bass-managed subwoofer and satellite speaker response for each of the candidate cross-over frequencies; and
select the candidate cross-over frequency resulting in the lowest objective function measure.
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Accused Products
Abstract
A system and method provide at least a single stage optimization process which maximizes the flatness of the net subwoofer and satellite speaker response in and around a cross-over region. A first stage determines an optimal cross-over frequency by minimizing an objective function in a region around the cross-over frequency. Such objective function measures the variation of the magnitude response in the cross-over region. An optional second stage applies all-pass filtering to reduce incoherent addition of signals from different speakers in the cross-over region. The all-pass filters are preferably included in signal processing for the satellite speakers, and provide a frequency dependent phase adjustment to reduce incoherency between the center and left and right speakers and the subwoofer. The all-pass filters are derived using a recursive adaptive algorithm.
54 Citations
20 Claims
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1. A signal processor configured to select a cross-over frequency to attenuate a spectral notch in a cross-over region, the signal processor comprising a configuration to:
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measure a full-range subwoofer and satellite speaker response in at least one position in a room, the full range subwoofer and satellite speaker response characterized by; select a cross-over region from the full range subwoofer and satellite speaker response; select a set of candidate cross-over frequencies and corresponding bass-management filters for the subwoofer and the satellite speaker; apply corresponding bass-management filters to the full-range subwoofer and satellite speaker response to obtain bass managed subwoofer and satellite speaker responses; level match the bass managed subwoofer and satellite speaker responses to obtain leveled subwoofer and satellite speaker responses; sum the leveled subwoofer and satellite speaker responses to obtain a net bass-managed subwoofer and satellite speaker response; compute an objective function measure using the net bass-managed subwoofer and satellite speaker response for each of the candidate cross-over frequencies; and select the candidate cross-over frequency resulting in the lowest objective function measure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A signal processor for attenuating an incoherent addition of satellite speaker and subwoofer acoustic signals, the signal processor comprising a configuration to:
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measure the full-range subwoofer and satellite speaker response in at least one position in a room, the full range subwoofer and satellite speaker response characterized by; select a cross-over region from the full range subwoofer and satellite speaker response; select a set of candidate cross-over frequencies and corresponding bass-management filters for the subwoofer and the satellite speakers; apply the corresponding bass-management filters to the subwoofer and satellite speaker full-range response; level match the bass managed subwoofer and satellite speaker response; sum the subwoofer and satellite speaker response to obtain a net bass-managed subwoofer and satellite speaker response; compute an objective function measure using the net bass-managed subwoofer and satellite speaker response for each of the candidate cross-over frequencies; select the candidate cross-over frequency resulting in the lowest objective function measure; filter speaker signals using the selected cross-over frequency and corresponding bass-management filters; and perform all-pass filtering on the filtered speaker signals to further attenuate spectral notches. - View Dependent Claims (16)
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17. A signal processor for selecting a cross-over frequency to attenuate a spectral notch in a cross-over region, the signal processor comprising a configuration to:
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measure a full-range subwoofer and satellite speaker response in at least one position in a room the full range subwoofer and satellite speaker response characterized by; select a cross-over region from the full range subwoofer and satellite speaker response; select a set of candidate cross-over frequencies and corresponding bass-management filters for the subwoofer and the satellite speaker; apply corresponding bass-management filters to the full-range subwoofer and satellite speaker response to obtain bass managed subwoofer and satellite speaker responses; level match the bass managed subwoofer and satellite speaker responses to obtain leveled subwoofer and satellite speaker responses; sum the leveled subwoofer and satellite speaker responses to obtain a net bass-managed subwoofer and satellite speaker response; compute an objective function measure using the net bass-managed subwoofer and satellite speaker response for each of the candidate cross-over frequencies; select the candidate cross-over frequency resulting in the lowest objective function; attenuate variations in the cross-over region by; define at least one second order all-pass filter having all-pass filter coefficients selectable to reduce incoherent addition of acoustic signals produced by the subwoofer and the satellite speaker; recursively compute the all-pass filter coefficients to minimize a phase response error, the phase response error being a function of phase responses of a subwoofer-room response, a satellite-room response, and the subwoofer and satellite bass-management filter responses; and cascading the all-pass filter with at least one of the satellite speaker bass-management filter and subwoofer bass-management filter. - View Dependent Claims (18, 19, 20)
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Specification