A Second Over-the-Ear Headphone Patent from Apple Specifically covers Wind Noise Reduction in Phone Calls
It was reported by Bloomberg in early March that Apple was working on noise-canceling, over-ear headphones that rival headsets from market leaders like Bose and even the company’s own 'Beats' by Dre brand. The timing to market wasn't known, though their sources had said that it could be towards the end of the year or sometime in 2019.
On November 8th Patently Apple posted a first patent report titled "Apple's latest Over-the-Ear Headphones Patent covers Noise Cancellation and Five-Mic Voice Beamforming Clarity." Today the US Patent & Trademark Office published a second noise cancellation over-the-ear headphone patent from Apple titled "System and Method of Wind and Noise Reduction for a Headphone."
Apple notes that a common complaint with most earphone or earbud devices used with telephony is that the speech captured by the microphone port or the headset includes environmental noise such as wind noise, secondary speakers in the background or other background noises. This environmental noise often renders the user's speech unintelligible and thus, degrades the quality of the voice communication.
Apple invention is focused on delivering an over-the-ear headphone with a method of overcoming wind and noise issues.
By reducing the wind and noise in the signals captured by the microphones, the speech quality and intelligibility of the uplink signal is enhanced. Specifically, embodiments of the invention spectrally mix signals from a microphone located inside the earcup (or ear bud, or phone) that is directed towards the ear canal (e.g., error microphone) with the signals from at least one microphone located on the outside of the earcup's housing to generate a mixed signal.
In some embodiments, the signals from the internal microphone is also subject to a version of an adaptive noise cancelling technique to further enhance the internal microphone signal before the spectral mixing.
Technically, a simple overview of a system of noise reduction for a headphone will include the following: "a speaker to output a speaker signal based on a downlink signal, an earcup of the headphone, an active-noise cancellation (ANC) downlink corrector, a first summator, a first and second acoustic echo canceller, an equalizer and a spectral combiner. The earcup includes a first external microphone included on an outside of a housing of the first earcup, and an internal microphone included inside the housing of the first earcup. The ANC downlink corrector processes the downlink signal to generate an echo estimate of the speaker signal. The first summator removes the echo estimate of the speaker signal from acoustic signals from the internal microphone to generate a corrected internal microphone signal. The first acoustic echo canceller removes a linear acoustic echo from acoustic signals from the first external microphone based on a downlink signal to generate an enhanced first external microphone signal and the second acoustic echo canceller removes a linear acoustic echo from the corrected internal microphone signal based on the downlink signal to generate an enhanced internal microphone signal. The equalizer scales the enhanced internal microphone signal to match a level of the enhanced first external microphone signal. The spectral combiner spectrally mixes the enhanced internal microphone signal with the enhanced first external microphone signal to generate a mixed signal. The lower frequency portion of the mixed signal includes a corresponding lower frequency portion of the enhanced internal microphone signal, and the higher frequency portion of the mixed signal includes a corresponding higher frequency portion of the enhanced first external microphone signal.
Apple's patent FIG. 3 below illustrates a block diagram of a system of wind and noise reduction for a headphone.
More specifically, Apple's patent FIG. 3 presents a noise suppressor (#308) that may suppress noise in the mixed signal based on the detector output received from the noise detector (#305). For example, when the detector output indicates that ambient or wind noise is detected, the noise suppressor removes at least one of a residual noise or a residual non-linear acoustic echo in the mixed signal to generate an enhanced mixed signal. The noise suppressor may be a one-channel or two-channel noise suppressor and may include a residual echo suppressor.
Apple's patent application was originally filed back in Q2 2017. To dive deeper into the invention's details, review patent application 20180343514 here.
Sorin Dusan: Senior DSP Engineer, Lead; Dusan has been with Apple since 2011 coming from Dolby Laboratories where he worked in Voice/Speech Processing.
Tom-Davy Saux: Audio Technology Engineer; Saux was Graduate Research Assistant at Virginia Tech at their Vibration and Acoustics Laboratories. Main projects focus on active noise control and acoustic imaging.
The third inventor listed is Bajic Vladan with no information about him found on LinkedIn.
While Apple fans were hoping for Apple's new over-the-ear headphones for Christmas, they were a no show. Instead Microsoft surprised the market by introducing their new Surface Headphones that are adjustable noise cancellation headphones at their fall "Surface" event.
Last week Marque Brownlee reviewed the best wireless headphones for the holidays and for him, Microsoft's headphones won over Bose and others which puts a lot of pressure on Apple to beat the new Noise Cancellation Headphone leader in town.