USE OF MIDI TO GENERATE SOUND:

As suggested by Professor Dymond, instead of generating and outputting pure tones, MIDI could be used to produce a wide range of sounds, including the sound of musical instruments to be output. For example, a drum bang can easily be output when a depth discontinuity is encountered instead of outputting the current pulse signal.

USE OF A MACINTOSH COMPUTER OVER THE SUN WORKSTATION:

The SUN workstation is fairly limited in terms of its audio capabilities. For example, it does not support MIDI. Also, the SUN is not portable, hence, any experimentation is restricted to the workstation room (i.e. one cannot perform any mobility tasks using the device blindfolded outdoors). In addition to supporting MIDI (both hardware and software), being portable, and its quality sound output, there is a great deal of sound related software available for the Macintosh making it the choice for many musicians and sound researchers. Any future work on this project should involve switching computer platforms to the Macintosh.

ELIMINATING THE EFFECTS OF THE 'CURVE OF EQUAL LOUDNESS':

As discussed previously, the magnitude of the pure tones output followed the 'Curve of Equal Loudness' (Fletcher-Munson curve) in which tones of different intensity levels are perceived to have the same loudness. Currently a 3.5kHz tone associated with a distance of 3.5m sounds louder than a 6kHz tone associated with a distance of 0.5m even though shorter distances are supposed to be mapped to louder sounds. A function could be created to eliminate the effect of the Fletcher-Munson curve. This would allow all frequencies to be perceived at the same magnitude thereby giving the user the choice of altering the magnitude or not.

EXPERIMENTATION:

With the use of a portable computer, blindfolded or visually impaired persons could use the device while performing simple mobility tasks (e.g. walking outdoors etc.) in order to determine the effectiveness of the device as a mobility aid.