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Multimedia: Applications in the teaching of building technology (acoustics)

Ray J Wilson
School of Architecture and Building
Deakin University

Introduction

For many years now, I have been regularly disappointed with the attitudes of many architects and building designers. It seems to me that too many of them do not think acoustics is an issue worthy of consideration in the majority of design projects. As a result, noise problems in even the simplest of building designs can sometimes eventuate. On a domestic level, one of the most common acoustic problems is noise from plumbing services. Have you ever been in a house where flushing the toilet made enough noise to disturb the entire household? Other major areas of concern include the control of noise intrusion from outside a building, eg. traffic noise. If only the building designer had made allowances for these factors in the design process!

It all comes back to the education of architects and building designers. If the quality of their education could be improved, maybe they would think a little more about acoustics when designing buildings. I became a lecturer in 1988 in an effort to improve this situation. I honestly felt that I could teach acoustics in such a way that future architects and building designers would become more concerned about possible acoustic issues.

This paper gives a brief account of how the use of multimedia is helping in my attempts to teach acoustics to architects and building designers of the future.

Traditional teaching methods

My first class of students were from the second year of the Architecture Degree at Deakin University, and totalled sixty five in number. At that time I felt the class size was very large but enthusiastically commenced weekly lectures of two hours duration. With the aid of some chalk, a blackboard, an overhead projector and some slides, I soon confirmed in my own mind that these would be totally inadequate and something special was required and as soon as possible. In an effort to give the students some practical training in acoustics, a variety of experiments were conducted. These experiments had been conducted in previous years, but never with so many students. Students were given the opportunity to borrow sound level meters for use in the field, as well as several laboratory tests were conducted by groups of five students. Supervision of these experiments involved two members of staff for a total of four full days each.

My desire to improve on the quality of acoustics instruction also led me to arrange site visits for all sixty five students to Melbourne's National Tennis Centre, Entertainment Centre and the Victorian Arts Centre. These visits were very much appreciated by the students, and I am sure they experienced many of the benefits of actually seeing, hearing and feeling the atmosphere in each of the buildings visited.

Why use multimedia?

Having survived 1988, my first year as a lecturer, I became quite frustrated on hearing that the 1989 acoustics class would exceed one hundred and thirty students in size. Not only did this mean the end to practical experiments and exercises, but even the Melbourne site visits became extremely difficult. It wasn't until early 1990 that I saw multimedia as an alternative to reverting back to chalk and talk acoustics classes.

Fortunately I had spent several years developing expertise in computer aided design (CAD) and had been appointed Manager of the School's Design Computing Centre. With such a resource at my fingertips, the prospective development of multimedia teaching aids gathered momentum very quickly. As the Design Computing Centre included both colour Macintosh II computers and IBM-PC type computers, my first major decision was which platform do I choose. At that time, the Macintosh multimedia concept had been developed far more than the IBM PC. As a result I elected to set up a Macintosh multimedia development system.

It was my intention to combine colour images from related videos with sound, text and animation in such a way that the experiments and site visits which were now almost impossible to organise could at least be simulated on the computer. This seemed an acceptable solution under the circumstances. In order to develop this simulated approach to acoustical experimentation, I required computer, audio and video hardware which could all be linked in a compatible manner. After testing several options in each area I purchased the following equipment. Its total value is approximately $30,000.

Equipment selection

Equipment selection

As mentioned earlier, a major component of my teaching and research responsibilities is in computer aided design. Much of the equipment illustrated is utilised in CAD research and development as well as acoustics.

The type and functions of the equipment illustrated is best described as follows:

Apple Macintosh H computer - 8 MB RAM, 160 MB HD, 8 bit colour card and monitor
NuVista (Classic) video graphics card - 4 MB VRAM
VIDI/O Box - video encoder/decoder
SVHS Video Camcorder and Tape Recorder
Stereo Audio System
MacRecorder sound digitisers (not shown)
Any audio signals can be digitised via the MacRecorders (one for each channel) and stored for replay on the Macintosh. The sampling rate is 22 kHz and is a little better than listening to your AM radio at home. The video signals from either the camcorder or VTR can be frame captured via the NuVista card inside the Mac in either 8, 16 or 24 bit colour quality. Computer images may also be recorded on the VTR, although the resultant VTR images are interlaced, causing them to flicker or strobe badly if not considered in the early stages of image development.

It was my intention to utilise the above system to develop computer graphics which could be superimposed over live video and recorded on the VTR, thus creating video tapes which have been enhanced with associated computer graphics and annotation. These video tapes would form the basis of 'view at home' lessons which would have related computer based exercises and demonstrations to be completed by the student in the Design Computing Centre. The above equipment has proved inadequate for this task. In order for the computer signal to be combined with a video signal for recording on another video tape recorder, a time base corrector is required. I have however successfully used a digital production mixer to mix the two signals and it is significantly less expensive than a time base correction device and offers some 'effects' features which may be of benefit. (At the time of writing this paper, a digital production mixer had been ordered, and was expected within a few days.)

Present achievements

As I have been unable to create the enhanced video tapes of site visits, laboratory experiments and photographic studies of acoustics in the manner which I considered most appropriate, all of the work produced so far has been computer based. Using MacroMind Director Software I have developed several exercises for acoustics students to utilise in addition to their weekly lectures.

The first of these exercises is not interactive, it simply uses sound, animation and text to explain a concept which is often difficult to explain in a class situation. The concept of sound shadows, and how frequency variation effects the shape and size of such a shadow, is easily explained using animated colour images, related sounds, and explanatory text. All of this is computer based, and runs automatically.

Another exercise requires the student to use mouse clicks to move to the next sequence of images and sounds. This exercise demonstrates the differences between pink and white noise and their frequency spectrum; a concept readily explained in this manner.

Probably the most significant project which I have developed in this computer assisted learning approach is the simulation of a sound level meter. Each student is given the opportunity to interact with the computer by using the mouse to adjust the settings on a colour image of a typical sound level meter. In developing this simulation, a variety of sound sources have been measured and recorded and the data supplied by these measurements inserted into the computer. The recorded sound is also digitised for computer playback when prompted by the student.

The student selects which of the sound sources they wish to measure, then an image of the source plus its sound is activated. eg. the 'circular saw' may have been selected, so a colour image of the saw will appear and a sound recording of the saw will become audible. At this stage the student can begin to feel part of the simulation! The next screen image to appear includes an animation of the sound level meter and the reading on the meter is showing less than zero on the scale. It is the student's task to adjust the settings on the meter using mouse clicks over the image until a positive meter reading exists. Once the correct settings are achieved, the student is able to read the sound pressure level of the source being measured. This exercise gives the student a clear understanding of the workings of a simple sound level meter without actually giving them one.

The future

With the addition of a digital production mixer, I expect to be producing video taped lessons, site visits and experiments, which will all have related interactive multimedia exercises on the School's computers. It is envisaged that such exercises will also require the student to pass a computer based question-answer quiz before proceeding to the next level of study. The final assessment in this subject will continue to be a traditional examination but I expect the results to improve with the ongoing development of this form of multimedia teaching.

Conclusion

Multimedia as an aid to teaching has obvious potential. The main constraints in developing multimedia courseware are generally going to be financial and time commitments. As university students are becoming more numerous, and resources are stretched to unreasonable limits due to budget cuts, the concept of using multimedia as an aid to teaching at university level is a positive one and should be encouraged. Unfortunately the financial outlay for even a basic multimedia authoring system and appropriate replay stations may prove prohibitive. At Deakin University's School of Architecture and Building, the Design Computing Centre's CAD equipped computers provide adequate replay equipment. The finance for the multimedia authoring system is generated mostly through extra income generating activities such as CAD Training Courses for external professionals. It is this income which makes the above described project possible.

Author: Ray J Wilson is a Lecturer in the School of Architecture and Building, Deakin University Geelong, Victoria, Australia.

Please cite as: Wilson, R. (1992). Multimedia: Applications in the teaching of building technology (acoustics). In Promaco Conventions (Ed.), Proceedings of the International Interactive Multimedia Symposium, 169-172. Perth, Western Australia, 27-31 January. Promaco Conventions. http://www.aset.org.au/confs/iims/1992/wilson.html

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