Mackie Designs Inc.

Ivl Technologies Ltd

Brian John Roden

Christopher Michael Jubien

Brian C Gibson

Dale John Shpak

Jeffrey William Sondermeyer

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 ().

Method and apparatus for automatic volume control in an audio system

A method for shifting the timbre and/or pitch of an input signal samples the input signal at a first rate and stores the samples in a memory buffer. A digital signal processor resamples the stored input signal at a rate that differs from the first rate at which the input note is originally sampled and stores the resampled input signal in a second memory buffer. A pitch shifter shifts the pitch of the input signal by periodically scaling the resampled input signal by a window function to create an output signal. The rate at which the resampled data is replicated by the window function determines the pitch of the output signal.

Method and apparatus for changing the timbre and/or pitch of audio

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Cobble Hill, Canada

Brian John Roden