Phase inversion filter for correcting low frequency phase distortion in a loudspeaker system
US9992573B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 2014 |
| Grant date | Jun 5, 2018 |
| Priority date | — |
| Expiry date | Mar 29, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R3/14
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A filter for correcting phase distortion produced at low frequencies in a loudspeaker system is created by inverting the phase response of the determined complex-valued frequency response of a loudspeaker system. The inverted phase response is obtained by taking the complex conjugate of the phase response. The impulse response for the inverted phase response is obtained by means of an inverse Fourier transform of the inverted phase response. The impulse response provides a linear phase FIR filter having a long filter length. The linear phase FIR filter is applied to the audio signal input to the loudspeaker system. Prior to inverting the phase response, the determined complex-valued frequency response of a loudspeaker system can be subjected to high frequency blanking and polynomial smoothing. Also, the linear phase FIR filter can be subjected to a window function prior to applying the filter to the audio signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.