Work Shop 7

A note about file links in this workshop:

As you work through this scenario, you should follow the steps as written. That is, if you read "I saved this file as XYZ.wav" you should save the file as XYZ.wav.

In many cases, by way of illustration, audio files representing intermediate steps in the design scenario will be available as an MP3 file for you to listen to. This is because MP3 files are easier to provide through the WWW. If you are working through the material you should not save your intermediate steps as MP3s, but keep working with wav files, only applying compression of necessary.

indicates a link to a file that has been provided by way of illustration. Clicking on will launch the sound in your computer's default media player. Should you wish to save the file to your hard drive right-click and select "save target as" (IE) or "save link as" (Netscape).

indicates a link to a file you will need to access to work through the example. You should right-click the link and select "save target as" (IE) or "save link as" (Netscape) to save these files to your hard drive.

WORKSHOP WEEK 7 MMST 12016

SOUND DESIGN 2

In last week's workshop we began an audio design project. We left off at the point where we had used techniques of audio synthesis, MIDI and digital audio processing to produce four sounds that will form the building blocks for the project. This week, we are going to manipulate the files from last week to produce a wider selection of sounds. In next week's workshop we will be assembling the sounds.

When you have downloaded these files, you should convert them to .wavs, and continue working with .wavs until the final assembly. To do this, open each file in your audio editor (SoundForge, SoundForgeXP or Goldwave, and save each one as a .wav. The four files you should begin working with will therefore be:

Throughout this workshop, you'll be able to listen to and download files from various intermediate stages. For convenience, they will be made available in the more compact .mp3 format.

Before I begin, I want to remind you that the focus of this and the last workshop is on design. This is not simply a technical exercise and the manipulations carried out are not arbitrary - although you might think of alternative ways of treating the sounds to meet similar aims.

In the last workshop, indicated that rather clichéd "computer noises" and monster sound effects effectively evoked fifties sci fi for me. In that part of the design process, the focus was on the symbolic meaning of the sounds: what generic "objects" the sounds represent or refer to. In refining the sounds, I want to focus on a different type of representation. While the selection of the sounds worked at a symbolic level, the refining and assembly of the sounds needs to flesh out the evocation of genre by intertextual reference to more abstract qualities than "computers" or "monsters".

The rationale for the choices I make in this workshop are once again quite subjective, and you might feel there are different or better ways to approach the design. If so, you should try to work further on this design project and produce a soundscape that works well for you.

In assembling the sounds, I want to certain qualities that I associate with the genre we are attempting to evoke. Before we begin, I'd like you to think about some of the affective qualities of B-grade sci-fi. Leaving aside the possibility that a contemporary audience is likely to engage with such a film ironically, think for a moment about the sorts of emotional responses it might be expected to evoke. Then scroll down to see what I suggest.

I think that we can assume that at least some of the following are can be associated with fifties sci fi:

As I work through the design of the final sounds, I wil explain how the formal ad tehnical parameters of the sound might work to evoke such affective qualities.

The first thing I want to do is create a sound that will form a background or backdrop for the soundscape. Since it is in the background, it needs to be relatively static in the way it develops (i.e. slow, steady, constant). I have chosen to begin with computernoise1.

Opening this file in SoundForge, I select a region that will work well as a loop. Note in the image below that the looping button is depressed. pressing "play" will then play the sound as a loop. Your editor might have separate play and loop play buttons, which should be easily identified.

I adjust the edges of the selection until am satisfied that the looping works well. This is partially guided by eye: note that the amplitude of the sound on the edges of the selection (the beginning and end of the loop) are fairly similar. Since computernoise one is a collection of simple tones, this works well as a guide. I then select Trim/Crop to remove the unwanted regions.

The next thing I want to do is slow the sound down, in order to make it more static. I do this in SoundForge by selecting "Process"->"time stretch".

Note that the current duration of the sound is 6.502 seconds. I increase this by a little over 50% by changing this time to 10.502 seconds.

Note also that Soundforge allows for a selection of different modes for time stretch. You should remember from the week lecture in week one the relationship between a sound wave's frequency and pitch. If you picture a sound wave as it is represented graphically, and imagine it being stretched to double its size, you can see that the frequency of the sound would have halved, and consequently the percieved pitch would have dropped. Since time stretch preserves original pitch, clearly something more complicated is happening. The different modes available in SoundForge reflect different mathematical processes acting on the digital representation of the original sound.

The next version of the computernoise1 sound I created was designed to evoke suspense by beginning quietly and gradually building. I achieve this in SoundForge by applying an amplitude envelope to the sound. In SoundForge, this is achieved by selecting "tools" -> "envelope". In GoldWave, the same result can be achieved by selecting "effects"->"volume"-."shape".

Next, I wanted to create a computer sound that would be in the foreground of the final soundscape. I therefore wanted it to be faster, brighter and generally more prominent. The first step was to speed the sound up. Using the same technique as above, I applied time compression. I reduced the sound to just under ten seconds.

For some reason, there was a gap created in the resultant sound, as shown below:

This probably should not have happened, but rather than re-apply the time compression, I decided to use this as an example of the sort of errors that can creep in when digitally processing sounds. It is important to listen to every step of the process in order to detect any degradation such as drop-outs, or pops.

In order to differentiate this further from the initial sound, I also reversed it. In SoundForge, this is achieved by selecting "process"->"reverse". In Goldwave, "effects"->"reverse" I named this file computernoise2rev.wav.

I wanted to increase my options by creating two more versions of this sound. In SoundForge, I added a simple delay effect. A delay is just that: a delayed version of the sound is added. By trial and error, I chose a small value, 0.139 seconds, for the delay. This meant that .139 seconds after the sound began playing, an "echo" of the sound at diminished volume also played.

The decay time controls how many repetitions of the echo there will be: the echo in principal occurs not just .139 seconds after the sound begins, but every .139 seconds, each time at a lesser amplitude. By keeping the decay time very small, I limit the delay effect to one echo only.

In order to create one more variation very quickly, I applied GoldWave's "mechanise" function to computernoise2fastrev.wav.

Usually it is bad practice to use readymade effects (it can have the same effect as using stock clip art in a publishing project). In this case, the effect is quite appropriate

I then copied a region of the sound, placed the cursor at the end of the sound and selected "edit"->"paste"

I then applied the graphical pitch bend effect, so that the sound would begin quite high and fast, and then drop in pitch and slow. In Sounforge this is achieved by selecting "effects" -> "pitch" -> "bend". In GoldWave, a very similar effect can be achieved by selecting "effects"->"doppler".

I thought this represented a sudden burst of some kind of mysterious computer activity, and, tiring of ever longer file names, called it cn2fburst.wav

The "monsterlow" sound from workshop 6 is developed enough for use in the final piece. However I did want to create a monster call to mix in to the final project.

I opened "monstelow.wav" and selected a region that I felt would work well as a monster's call.

While I wanted this sound to be abrupt, I did not want it to end or begin unnaturally, or to risk pops or other digital artefacts by ending at a high amplitude. This enforces a very sharp transition that can cause problems when the signal is further manipulated or converted back to analog for playback.

To do this I simply highlighted a small region, first at the beginning and then at the end of the sound, and chose "process"->"fade"->"in" (at the beginning, "out" at the end")

That concludes the work-through for this week. If you have time left over, you should attempt the following exercise:

A radio play has been commissioned in which a group of time-travelling scientists visit the Jurassic era. You must create sound effects to represent various dinosaurs. Describe three different dinosaurs - you don't need to be scientifically accurate. For example, you may wish to choose a large, fierce carnivore, or a small, fast-moving birdlike creature.

Using the animal sounds in the resources section as source material, and the techniques covered in the week 6 and week 7 workshops, create sound effects to represent each of the dinosaurs

Workshop Week 7

WORKSHOP WEEK 7 MMST 12016

SOUND DESIGN 2