If you get a soft and gentle default alarm tone on smartphones that use Android, why is it that the Apple iPhone's default alarm tone so annoying?
Well, as it turns out, there are a few good reasons for this – according to Apple.
Apple's default alarm tone for the iPhone is called Radar, and it features a rather striking and quite frankly annoying sound. This was designed intentionally by Apple as the "Radar" effect has a short, sharp and rapidly occurring tonal sound. Its short decay time is set at a frequency of 2-5Hz, which happens to be very sensitive to the human ear sensors.
This is designed to wake you up as quickly as possible, which results in the average human being less tired shortly thereafter. Furthermore, studies have shown that using your favourite song as your alarm tone will psychologically turn it into your least favourite due to the negative association.
The Radar alarm tone can be considered a "Shrill Tone", similar to that of running your nails over a chalkboard.
Take a look at the video below by the YouTube channel, Apple Explained, on Why The iPhone Alarm Tone Is So Annoying...