3. Auditory Interfaces

People are very social beings and interact with their environment in many ways (O’Shaughnessy 2003). Information can be received through seeing, hearing, smelling, tasting or feeling, while, conversely, it can be sent back into the environment visually, vocally, and through body gestures. Interaction between a user and a machine is performed through a user interface that consists of various hardware and software components. Its main functionality is to transform the users’ orders and requirements into a set of machine commands and also to provide the corresponding feedback to the user, preferably in real-time. The available communication channels between a user and a machine are limited by human senses and their capabilities on the one hand and the technological restraints of input–output devices on the other. The primary communication channels for the majority of people are seeing and hearing, and consequentially visual and auditory interfaces are the dominant types of user interfaces in the HMI domain. The major paradigm of our times is undoubtedly mobility. The mobile life, such as driving a car, cycling or walking, requires a lot of visual attention. Interacting through a visual interface in these situations leads to distraction from one’s primary task and consequently to a difficult, dangerous, ineffective and potentially frustrating user experience. In this chapter we present the basic properties and advantages of auditory interfaces that offer an excellent alternative to Human-Machine Interaction (HMI) in visually-demanding mobile situations. Auditory interfaces are very flexible and they do not interfere significantly with the reception and processing of visual information.