No noise reduction for the hearing impaired
The noise cancellation for calls that was present on previous iPhones appears to be missing on the iPhone 13. Previously it was thought that it was a software bug – and some Apple Support employees still seem convinced. But inquiries by 9to5Mac give a very different impression: the feature may have been deliberately removed and the situation is permanent. If you want to make calls with adjustable noise reduction, Apple recommends using the AirPods Pro or similar earplugs. These ensure that conversations on the other end of the line are easier to understand.
It is important to know that this is noise reduction with adjustment options. Normal noise cancellation for regular phone calls is still there, but not customizable for users.
On models other than iPhone 13, go to Settings > Accessibility > Audiovisual. There you will find the option for noise reduction to minimize ambient noise during a call when you hold the device to your ear. The other person can then concentrate better on the conversation.
According to Apple Support “it is not supported” on the iPhone 13 models. At least, that's the view a reader of 9to5Mac was told. If you disagree, Apple advises you to use the feedback option to express your dissatisfaction.
That's correct. It is not supported. If you would like to leave feedback about this feature, please feel free to visit: apple.com/Feedback.
Not intentionally left out after all?
When asked, however, the AppleInsider site was still told that it was a bug, which will be resolved in due course. This was also the position before. It is difficult to say who is right. An official support article in which the iPhone 13 series is explicitly omitted is not yet available on the site. Either way, it's an unusual choice to permanently remove a useful feature for people with hearing impairments. The iPhone 13 has all the microphones and other parts to get the function working.
The problem has been going on for several months, since October when the first reports about the missing function appeared on Reddit.