Sound
Use sound to provide cues and feedback, and to create the desired ambiance

Ringing phoneThe real world is full of sounds that create ambiance and provide us with cues and feedback. RealThings should provide user options for sound support, including the ability to turn sounds off, and select levels of sound support. Sounds should be consistent with their real-world equivalents to ensure that they correspond to the user's expectations.

We suggest separating sounds into three types: background or ambiance creating sounds, such as a ticking sound for a clock; normal function sounds, such as a click when a button is pushed; and alarm sounds when events occur that require the user's attention, such as a cuckoo sound for a clock, or a bell for a ringing telephone.