Sometimes audio devices suffer from the “howls.” Apple wants to eliminate this issue with its AirPods and Beats devices. The company has been granted a patent (number 11,250,833) for a “method and system for detecting and mitigating audio howl in headsets.”
About the patent
In the patent filing, Apple notes that headphones and earphones provide a convenient method by which the user can individually listen to audio content without having to broadcast the audio content to others who are nearby.
However, there can be feedback issues. Audio feedback is a special kind of positive loop gain which occurs when a sound loop exists between an audio input (for example, a microphone or guitar pickup) and an audio output (for example, a power amplified loudspeaker).
When using speakers, earbuds, or headphones, a microphone may pick up their sound and create a howling sound. To reduce the howling/robot/echo sound, you have to use a headset instead of speakers. If you don’t have a headset, reduce the speaker volume and keep the speakers away from the microphone.
Apple wants to perfect an audio system that can detect and mitigate audio howl that is caused while the system operates in one of several audio output modes
Summary of the patent
Here’s Apple’s abstract of the patent with the technical details: “A method performed by an audio system that includes a headset with a left headset housing and a right headset housing. The method includes driving a speaker of the left headset housing with an audio signal, determining whether audio howl is present within the left headset housing by comparing spectral content from a first error microphone signal produced by a first error microphone of the left headset housing and spectral content from a second error microphone signal produced by a second error microphone of the right headset housing, and, in response to determining that audio howl is present, filtering the audio signal to mitigate the audio howl.”