1.6.1 The role of sound
The use of sound is becoming increasingly common, particularly for the following types of application.
Applications where the eyes and attention are required away from the screen. Relevant examples include flight decks, medical applications, industrial machinery and transport. If you are a runner, you may have a heart rate monitor that allows you to monitor how fast your heart is beating. This is often indicated by an auditory beep, which speeds up as your heart rate increases. In some monitors, the beep stops when your heart is within the target range. This can be extremely off-putting as it is ambiguous: either you are within the target range or your heart has stopped beating altogether!
Applications involving process control. In some process control applications alarms must be dealt with, or continuous monitoring is required. In these situations the sound indicates a system change, which the user may need to attend to. For example, some print managers speak relevant phrases when problems occur, such as ‘out of paper’ or ‘printer jam’.
Applications addressing the needs of visually impaired users. Screen readers are particularly important for visually impaired users. These read out the content of the screen. It is important to follow certain layout conventions in order to make screen readers as usable as possible. The Bobby standard provides assistance with designing web pages for visually impaired users.