Yesterday I saw this 2016 video where two sound designers react and explain some of the world’s most recognizable sounds. Exactly a day before I had shown some of these sounds to some product design students and it is quite amazing how we are all so tuned into these auditory interfaces.
At some point on the vídeo, about the Marimba iPhone ring, they mention some research made in Bell Labs about the best parameters for a ring tone.
Looking for a bit more info, I found this article about this ringtone, and it says:
“Scientists at Bell Laboratories, Human Factors Research Lab performed numerous studies on ringers, from buzzers to thumpers. They studied tonal quality and duration along with the decibel levels needed for the brain to recognized the call alert. They even tested the Grandpa to the iPhone “old phone” ringtone. In 1956, 300 research subjects in Crystal Lake, Illinois found the “musical tone ringer” to be “pleasant,” but took most test subjects over a week or so to get accustomed to it. However, when pressed, a majority of test subjects wanted the old bell ringer back. Not much has changed since from the days of the early Human Factors research, the brain still works the same, but the technology obviously allows for more finite control of the sounds a ringtone creates.
Ideally, a ring tone should register very clearly and distinctively in the audio range that is central to human hearing, from about 2 to 4 KHz, with a Dynamic range (quietest to loudest) of about 96 dB. Even though this audio range is quite crowded with a lot of sound, it is also precisely where most spoken languages carry a majority of phoneme distinction, and thus, we have evolved a relatively high level of sound discrimination central to this audio range.
For a ringtone to be decoded ideally by the brain, the timbre of the audio envelope ideally should pulse to a full dynamic range to nearly no sound with-in a 3 – 5 second cycle (Bell Labs Research). The relative amplitudes of the various harmonics primarily determine the timbre of instruments and sounds, though onset transients, formants, noises, and inharmonicities also play a role.“