And here is how Apple tests the iPhone registration videos.

The title of CNET on "the rare perspective inside Apple's secret labs for the new iPhone 16 camera" is somewhat hyperbolic, given that there is nothing secret: we have already seen one before.

But the same piece also provides an interesting glimpse into some of the testing processes used during the development of a new iPhone.

Our first look at Apple's anechoic chamber was in 2018, when the company presented it to The Loop, followed by a second one only a few months later, when Apple shared photos in a news release about AirPods.

CNET showed some of the ways in which Apple verifies the microphones used for recording iPhone video ringtones, demonstrated with the iPhone 16.

There is an array of speakers (around two dozen) mounted on a tubular arc that runs from the floor beneath the wiring network to the ceiling of the environment. The speakers emit a series of chills and the engineers measure what the iPhone 16 Pro microphones record. The phone, mounted on a stand above a rotatable base, rotates a few degrees clockwise and the chills repeat. This continues until the iPhone has completed a full circle.

The result is a spherical sound profile for each microphone created by the data recorded in the anechoic environment. Apple uses these profiles as the basis for spatial audio and other software that can reduce wind noise or make the audio recorded with the iPhone seem to come from different types of microphones – think a flexible microphone or studio voice-over microphone.

Davide explained that they want to enable the [Audio Mix] feature as if recording it with a throat microphone. We use machine learning algorithms, along with our calibration chains, to create that distinctive sound you can also get with throat microphones.

It is intriguing that while the main evaluation of the results is done by "the golden ear" of Apple's acoustic leadership Ruchir Dave, they also test various versions with ordinary iPhone users.

Instead of having only one person with a good ear to adjust the audio of the iPhone, Apple has numerous testers who perform an auditory perceptual test and then use these results to calibrate what you hear reproduced on your iPhone. I also had the opportunity to be one of these testers while there and spent part of my experience [...]

Apple uses the comparison between two options as a doctor might do during an eye exam, presenting you with two different lenses to select from. Without something to reference and compare against, it is more difficult to evaluate an audio recording. The results of sensor testing influence how the iPhone 16 Pro audio works in various aspects, including the audio mix mode.

For video verification, Apple has a video verification laboratory – essentially, a way to ensure that the final result continues to look beautiful under many different real-world conditions.

We use this theater to adjust video playback experiences so that, regardless of where you watch them – in a dark room, in an office environment or even in the sun – you get the same sensorial experience as if you were watching a movie in theaters," said Sean Yang, Apple's video engineering director.

They do not share any deep secrets, but it is still an interesting look at how much care Apple puts into the smallest details.

Photo: Apple