Audio feedback

Visual and audio feedback information is provided to the user by light-emitting diodes (LED), liquid crystal displays (LCD), and piezoelectric transducers. This information can indicate that the system is working, show errors or warnings, signal system maintenance needs (such as battery replacement), or display the amount of drug that has been delivered. 

Manufacturers aiready include basic audio and vibrotactile features in products like mobile phones. Unfortunately, when the device is in a bag or pocket, tactile feedback can go unnoticed. If a user is iistening to music, audio feedback can be ineffective. Thus, mobile applications could benefit from providing alternative presentation modalities depending on the situation. As the context changes, so should the feedback modality. This research exploits existing features of mobile devices by making information available to both the auditory and tactile senses so that the user can receive the information in the most suitable way. 

Positive feedback represents a controller contribution that reinforces the error therefore, it precludes stability. Consider the audio feedback that occurs when a microphone is placed too close to the speaker that amplifies the microphone s output. Sound from the miCTOphone is amplified through the speaker. If this sound re-enters the microphone, it adds to itself, and so on until the speaker saturates with a deafening tone. This is an example of positive feedback. Since positive feedback has no useful purpose for automatic control, we will consider it no further. 

Maxwell and Zurek, 1995] Maxwell, J. and Zurek, P. (1995). Reducing acoustic feedback in hearing aids. IEEE. Trans. Speech and Audio Proc., 3 304-313. 

Dyrlund and Bisgaard, 1991] Dyrlund, O. and Bisgaard, N. (1991). Acoustic feedback margin improvements in hearing instruments using a prototype DFS (digital feedback suppression) system. Scand. Audio .., 20 49-53. 

Rocchesso and Smith, 1997] Rocchesso, D. and Smith, J. O. (1997). Circulant and Elliptic Feedback Delay Networks for Artificial Reverberation . IEEE Trans. Speech and Audio Processing, 5(1 ) 51—63. 

Acoustic displays can be used to provide feedback concerning the virtual environment. Sound plays an important role in localization and interaction. Due to the application of simple audio in many other areas outside of VE, it is known as a mature technology. Synthesizers creating, mixing, and reproducing sounds and systems for speech in- and output have been made available. 

The pilot needs to gain the right information (or feedback) at the right time from the displays in the cockpit. Feedback may be visual, via audio, tactile or haptic. Depending on the case, the feedback has different objectives ... 

An output device is any tool that delivers information from a machine to a human. Again, the most familiar output devices are those associated with personal computers monitors, flat-panel displays, and audio speakers. Other output devices include wearable head-mounted displays or goggles that provide visual feedback directly in front of the user s field of vision and full-body suits that provide tactile feedback to the user in the form of pressure. 

Not only does multitone eliminate the step-and-repeat process, but it can also provide immediate feedback for equipment adjustments. Watching the entire audio spectrum respond to interactive adjustments with little or no time lag further simplifies audio equipment calibration. 

Before the actual presentation, practice is essential. (It may surprise you to learn that most faculty do not practice their lectures.) If possible, practice in front of real audience members who have agreed to give you feedback. Otherwise, try taping (audio or video) your presentation and critiquing it yourself. If none of these techniques will work, go to a quiet room and give your presentation out loud to yourself. In any case, it is best if you use the actual equipment (overhead projector, slide projector, and/or conputer) that you will use in the actual presentation. If this is inpossible, use hard copies of your visuals. 

Abstract. Mobile device users can be in a variety of different situations where visual, audio, or tactile feedback is not appropriate. Tbis research aims to investigate the design of auditory/tactile crossmodal icons which can provide an alternative form of output using the most appropriate modality to communicate information. The results of this research will aid designers of mobile displays in creating effective crossmodal cues which require minimal training and provide alternative presentation modalities through which information may be presented if the context requires. 

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