William Dell
Department of Computing Science, University of Glasgow.

The Final Report

Auditory alarms are being used in many safety critical environments such as hospitals, nuclear power stations and aircraft. At present, these auditory alarms rarely make use of the fact that sound can be processed to come from more than one direction. Looking at aviation in particular, it is common for pilots to wear headphones that support stereo sound, which means that taking advantage of this aspect of audio is certainly feasible. Additionally, a 3D virtual acoustic display was proposed by Wenzel [1] when there was insufficient technology to test her assertions. However, with the release of DirectX 5.0, it is now practical to design and prototype auditory alarms that make use of 3D audio. This project investigates the impact of using spatialised alarms versus stereo and mono alarms. The effectiveness of the three types of alarm are analysed in terms of reaction time, error rate, learnability, performance of primary task and workload measures. The results from this experiment indicate that the technology for supporting 3D audio is not sufficient to yield an advantage over it’s alternatives.

To run the mono version of the experiment.

Few browsers currently support applets that play stereo audio files (May 2000). If you want to run the stereo or 3D conditions then you will need a version of the appletviewer provided with JDK1.2.2 or better. Once you have this, follow these steps:

1. copy across this zipped file;
2. extract its contents using unzip or simply by double-clicking on it;
3. this should, amongst other things, give you three batch files, mono.bat, stereo.bat and 3D.bat. Run them by double-clicking in the usual way.

Warning: you must specify the location of the appletviewer in autoexec.bat:
SET PATH = < path of appletviewer >
Alternatively you can edit the three batch files and add the location of the appletviewer directly. If you are in doubt about any of these instructions then please consult your local systems administrator.

Once you have installed the program and confirmed that you are ready to run the experiment, you must hold down the left mouse button and drag it in the opposite direction to the circle. This will drag the target in the centre of the screen back inside the circle. This is the primary task.

As you work to keep the target inside the circle, you will hear a number of audio notifications. These are associated with a number of fundtion keys on the outside of the applet window. You should confirm that you have recognised these notifications by pressing the appropriate function key as soon as you have heard the warning.