Mackie Designs Inc.

Jeffrey William Sondermeyer

Dale John Shpak

Christopher Michael Jubien

Brian John Roden

Constantine Lakoumentas

An audio system () is provided with improved adaptive filter () to automatically adjust signal gain depending on the ambient noise level. The original music signal passes through a normalized adaptive filter (), and is subtracted from the ambient room signal detected by a microphone (), resulting in an error signal that is an estimate of the ambient noise. The error signal is used to update a set of adaptation coefficients so that the normalized adaptive filter more accurately simulates the room transfer function, resulting in an better estimate of the ambient noise. The audio system () is calibrated automatically upon initial use to determine adaptation coefficients and noise threshold level to prevent runaway gain. System parameters are adjusted using a controller () with a user-friendly interface ().

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Bothell, WA, United States of America

Jeffrey William Sondermeyer