ACTIVE ROOM COMPENSATION IN LOUDSPEAKER SYSTEM
First Claim
1. A method for compensating for acoustic influence of a listening room on an acoustic output from an audio system including at least a left and a right loudspeaker, the method comprising:
- determining a left frequency response LPL between a signal applied to the left speaker and a resulting power average in a listening position,determining a right frequency response LPR between a signal applied to the right speaker and a resulting power average in the listening position,designing a left compensation filter FL,designing a right compensation filter FR,during playback, applying the left compensation filter to a left input signal, and applying the right compensation filter to a right input signal,providing a simulated target function HT representing a simulated target response in the listening position,designing the left compensation filter FL to have a left filter transfer function based on the simulated target function HT multiplied by an inverse of the left frequency response, anddesigning the right compensation filter FR to have a right filter transfer function based on the simulated target function HT multiplied by an inverse of the right frequency response.
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Abstract
A method for compensating for acoustic influence of a listening room on an acoustic output from an audio system including at least a left and a right loudspeaker, the method comprising determining a left frequency response and a right frequency response, designing a left compensation filter FL, and a right compensation filter FR, and during playback applying the left and right filters to left and right channel inputs. According to the invention, a target response in the listening position is simulated, and the left and right compensation filters are designed to filter transfer functions based on the simulated target function multiplied by an inverse of the left/right frequency responses. By relying on a simulated target instead of relying on an empirical approach, the general impact of a room can be more accurately captured by the target functions.
2 Citations
29 Claims
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1. A method for compensating for acoustic influence of a listening room on an acoustic output from an audio system including at least a left and a right loudspeaker, the method comprising:
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determining a left frequency response LPL between a signal applied to the left speaker and a resulting power average in a listening position, determining a right frequency response LPR between a signal applied to the right speaker and a resulting power average in the listening position, designing a left compensation filter FL, designing a right compensation filter FR, during playback, applying the left compensation filter to a left input signal, and applying the right compensation filter to a right input signal, providing a simulated target function HT representing a simulated target response in the listening position, designing the left compensation filter FL to have a left filter transfer function based on the simulated target function HT multiplied by an inverse of the left frequency response, and designing the right compensation filter FR to have a right filter transfer function based on the simulated target function HT multiplied by an inverse of the right frequency response. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 27)
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21. A method for smoothing a frequency response between a signal applied to a speaker and a resulting power average in a listening position, comprising:
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determining a number of peaks per octave in the response, for a portion of the response where the number of peaks per octave is below a first threshold, smoothing the response with a first smoothing width, for a portion of the response where the number of peaks per octave is above a second threshold, smoothing the response with a second smoothing width, wherein said second threshold is greater than said first threshold and said second smoothing width is wider than said first smoothing width, and for a portion of the response where the number of peaks per octave is between the first and second thresholds, smoothing with an intermediate smoothing width. - View Dependent Claims (22, 23, 24, 25, 26)
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28. An audio system including:
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at least a left and a right loudspeaker arranged in a listening room; at least one microphone arranged in a listening position; a signal processing system for compensating for acoustic influence of the listening room on an acoustic output from the loudspeakers, said signal processing system being configured to; apply a test signal to the left speaker, determine a power average based on a signal measured in the microphone, and determine a left frequency response LPL between the test signal and the power average, apply a test signal to the right speaker, determine a power average based on a signal measured in the microphone, and determine a right frequency response LPL between the test signal and the power average, design a left compensation filter FL, and design a right compensation filter FR; and a filtering system configured to; during playback, apply the left compensation filter to a left channel input, and applying the right compensation filter to a right channel input, wherein the signal processing system is provided with a simulated target function HT representing a simulated target response in the listening position, and in that the signal processing system is configured to design the left compensation filter FL to have a left filter transfer function based on the simulated target function HT multiplied by an inverse of the left frequency response, and design the right compensation filter FR to have a right filter transfer function based on the simulated target function HT multiplied by an inverse of the right frequency response. - View Dependent Claims (29)
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Specification