US 10,455,326 B2 · Audio feedback reduction utilizing adaptive filters and nonlinear processing

Abstract

Traditional audio feedback elimination systems may attempt to reduce the effect of the audio feedback by simply scaling down the audio volume of the signal frequencies that are prone to howling. Other traditional feedback elimination systems may also employ adaptive notch filtering to detect and “notch” the so-called “singing” or “howling” frequencies as they occur in real-time. Such devices may typically have several knobs and buttons needing tuning, for example: the number of adaptive parametric equalizers (PEQs) versus fixed PEQs; attack and decay timers; and/or PEQ bandwidth. Rather than removing the singing frequencies with PEQs, the devices described herein attempt to holistically model the feedback audio and then remove the entire feedback signal. Two advantages of the devices described herein are: 1.) the system can operate at a much larger loop-gain (and hence with a much higher loudspeaker volume); and 2) setup is greatly simplified (i.e., no tuning knobs or buttons).

Claims20

Dependent claims

A system for eliminating audio acoustic feedback, comprising:

one or more speakers configured to produce an output audio signal;
one or more microphones configured to capture an input audio signal, wherein the input audio signal may comprise at least a portion of the output audio signal;
an audio mixer operatively coupled to the one or more microphones;
an audio amplifier operatively coupled to the one or more speakers;
and
a feedback elimination system operatively coupled between the audio mixer and the audio amplifier, the feedback elimination system configured to:
analyze, using a subband data structure having a crossover frequency, the input audio signal, wherein the subband data structure uses a first subband decomposition operation and a second subband decomposition operation, and wherein each subband comprises two or more adaptive filter taps;
estimate an echo return loss in the input audio signal;
detect a double talk condition in the input audio signal;
suppress echo in the input audio signal based, at least in part, on the analysis of the input audio signal, the estimated echo return loss, and the detected double talk condition;
and
synthesize the output audio signal based, at least in part, on the input audio signal with suppressed echo.

9 more elements

Dependencies are inferred from the claim text.

Audio feedback reduction utilizing adaptive filters and nonlinear processing

Life of this patent

Audio feedback reduction utilizing adaptive filters and nonlinear processing

Life of this patent

Abstract

Claims20