Home Correction app The process behind Apple’s “Noise” application, Acoustic Dosimetry, will be added to future AirPods and HomePod mini

The process behind Apple’s “Noise” application, Acoustic Dosimetry, will be added to future AirPods and HomePod mini


In 2019, Apple introduced watchOS 6 with advanced health capabilities, including a “Noise” app. At the time, Apple said that “the Noise app helps users understand sound levels in environments such as concerts and sporting events that could negatively impact hearing. changes, the app’s decibel meter moves in real time. The watch may send a notification if the decibel level reaches 90 decibels, which may start to impact hearing after four hours per week of exposure to it. level, according to the World Health Organization. “

Today, the US Patent and Trademark Office released a patent application from Apple that relates to this specific topic.

Apple notes that Acoustic dosimetry can be a process of measuring audio exposure over a period of time (e.g., hour, day, week, month, etc.) to provide a cumulative audio exposure reading (e.g. example, a sound pressure level value (SPL)). It appears to be distinct from the noise cancellation found in AirPods today.

According to Apple, a listener can be exposed to user-desired audio content (eg, music) through an audio output device, such as headphones worn by a listener. Acoustic dosimetry can also relate to the measurement of a listener’s exposure to ambient noise. To measure environmental noise, an electronic device (for example, an SPL meter) captures noises (for example, using a microphone) that are near a listener, and generates an SPL reading (for example, using a microphone). example, by displaying the reading on an SPL counter display screen).

Prolonged periods of exposure to loud sounds have been shown to cause hearing loss (eg, noise-induced hearing loss (NIHL)). NIHL is attributed to damage to microscopic hair cells inside the inner ear due to exposure to loud sounds. For example, prolonged exposure to sounds equal to or greater than 85 dB can cause temporary or permanent hearing loss in one or both ears. Therefore, some organizations (for example, the National Institute for Occupational Safety and Health (NIOSH) have recommended that workers’ exposure to ambient noise be controlled below a level equivalent to 85 dBA for eight hours in order to minimize the exposure of workers to ambient noise. NIHL professional.

Electronic headsets have become increasingly popular with users as they reproduce media such as music, podcasts, and movie soundtracks with high fidelity while not disturbing other people nearby. Recently, the World Health Organization (WHO) published hearing health safety standards that limit the maximum sound output from headphones to 85 dBA.

In order to meet this standard, an acoustic dosimetry process (for example, performed in the headset or other electronic device associated with the headset) can monitor an in-ear SPL at the headset and notify (or alert) a user when the sound exceeds this threshold.

Specifically, the acoustic dosimetry process measures or estimates the in-ear SPL, for example, at or near a reference point on the eardrum, during sound playback. In one aspect, the in-ear SPL is measured as follows. The signal from an internal microphone in the headset, which picks up all sound in the ear canal, can be transformed into an equivalent SPL, for example using laboratory calibration results that include correction factors, for example equalization , to be applied to the microphone signal. These correction factors may explain an occlusion effect in which headphones at least partially obstruct the user’s ear canal.

The in-ear SPL can be determined during playback through the headset worn by the user. Once estimated, the in-ear SPL is converted into a sound sample whose units are defined by hearing health safety standards.

These sound samples can then be used by the dosimetry process to track the audio exposures from the helmet. This conversion of the in-ear SPL to sound samples, however, may be unnecessary when the sound is reproduced in the ambient environment, for example through a loudspeaker. Therefore, it may be necessary to determine the type of audio output device through which a listener listens to sound in order to properly configure a dosimetry process (for example, to convert in-ear SPL values ​​when the output device is a helmet).

To overcome these deficiencies, Apple’s patent application describes an audio system capable of configuring a dosimetry process based on determining whether the listener is listening to sound through headphones or a speaker.

More specifically, the audio system may include an audio source device that transmits an audio output signal to an audio output device to cause a speaker to output sound. A microphone signal is obtained from a microphone in the audio source device, which captures the emitted sound.

The audio system determines whether the audio output device is headphones or a speaker based on the microphone signal.

Apple’s patent FIG. 1A shows the audio system which includes the audio source device and an audio output device; FIG. 2 shows a block diagram of an audio system which configures the audio source device based on a type of audio output device. It is here in the controller that we see that it is configured to perform Acoustic Dosimetry process operations at # 20 in the diagram below.

For more details, see Apple patent application number 20210358515. As this is a patent application, the timing of such product marketing is unknown at this time.

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