Methods and apparatus to reduce noise from harmonic noise sources

An apparatus to reduce harmonic noise, the apparatus comprising:

• at least one memory;
• computer readable instructions in the apparatus;
• processor circuitry to execute the computer readable instructions to at least:
• determine a first amplitude value in a frequency spectrum of an audio sample;
• determine one or more points in the frequency spectrum having at least one of (a) a second amplitude value within an amplitude threshold of the first amplitude value, (b) a frequency value within a frequency threshold of the first amplitude value, or (c) a phase value within a phase threshold of the first amplitude value;
• generate a contour trace, wherein the contour trace includes at least one of the determined first amplitude value and the determined one or more points;
• based on the contour trace, modify the audio sample;
• and
• determine if the contour trace is an outlier based on a distance from a parameter of the contour trace.

A method to reduce noise from harmonic noise sources, wherein the method comprises:

• determining a first amplitude value in a frequency spectrum of an audio sample;
• determining one or more points in the frequency spectrum having at least one of (a) a second amplitude value within an amplitude threshold of the first amplitude value, (b) a frequency value within a frequency threshold of the first amplitude value, or (c) a phase value within a phase threshold of the first amplitude value;
• generating a contour trace, wherein the contour trace includes at least one of the determined first amplitude value and the determined one or more points;
• and
• based on the contour trace, modifying the audio sample;
• and
• determining if the contour trace is an outlier based on a distance from a parameter of the contour trace.