# Audition and Sound

## 2. Exploring Sound

In order to understand what we are doing in this lab, it is helpful to go through some terminology and learn about sound and how it is stored. Once you understand a little about sound, we will record sound using a Zoom H4n device and edit it using Adobe Audition.

### 2.1 What is Sound?

The answer to the question of, "what is sound?" is really a physics answer. Have you ever struck a tuning fork and placed it in water or dropped something in water? If you have, you would have seen waves. Sounds are waves in air, which are picked up by sensors in our ears. Because sounds are waves, let us take a look at a basic sine wave (which we would hear as pure single tone).

Picture was taken from: http://www.purplemath.com/modules/grphtrig.htm

Some important definitions are:

• cycle. Take a look at the graph and notice that there is one "up peak" and one "down peak". The completion of the up and down "wave" is one cycle.

• amplitude. Notice how the graph starts at 0 and goes up to 1 and eventually goes down to -1. The distance from zero to the greatest (or least pressure) is the amplitude. In the diagram above, the amplitude is 1. "In general, amplitude is the most important factor in our perception of volume: if the amplitude rises, we typically perceive the sound as being louder" (page 147, Computing and Programming in Python, A Multimedia Approach by Mark Guzdial)

• frequency. How often a cycle occurs is called frequency. Frequency is measured in cycles per second (cps) or Hertz (Hz). Frequency and pitch are related: the more cycles, the higher the pitch.

Questions:

1. Would the following diagram represent a sound with a higher or lower pitch than the original sine wave diagram?

2. Would we perceive this sound to be louder or quieter than the original sine wave diagram?

The sounds that we hear are not typically pure tones: they will be composed of waves of different frequency. When you are looking at sound waves in the following sections, you will see more rough edges than the smooth and regular sine waves. This is the result of several frequencies combining together.

### 1.2 How is Sound Stored?

If you want to capture a sine wave such as the above, you could use an array. For instance taking a sample at (π/2)t, your array would look something like this:

0 3 0 -3 0 3 0

The resulting "wave" would look very triangular. Ideally, more samples could be taken. However, you can understand the idea of representing the wave.

Two questions come in to play when storing sound:

1. What is the maximum amplitude to be stored? This will determine how many bytes in memory you will use for each sound sample or array element. For instance, if you want to capture amplitudes from 32 767 (215-1) to -32 768 (-215), then you will need 16 bits (2 bytes) for each element.

2. How many samples or array elements will you have for every second of recording? For instance, the array above could have more samples to "smooth" the wave. The rate at which samples are collected is the sample rate. Some typical sample rates are below:
• For CD-quality sounds: 44 100 samples per second. That means that one minute has 60 x 44 100=2 646 000 elements.
• Our telephone is designed to capture 8 000 samples per second. That means that one minute has 60 x 8 000=480 000 elements

Now that you understand a little more about sound, let us dive in with doing some recordings and editing.

## 3. Zoom H4n

Quick start guide on how to create your first recording:

How to delete files that you've recorded:

Other videos or resources that might be useful:

## 4. Audition and SoundCloud

We will be going through some of the content in this video starting from about 5:30 when it talks about multi-track sessions.

Highlights to cover:

• Setting up a multitrack recording
• Dragging audio samples onto the tracks
• Changing the length of the sound sample
• Adjusting the volume of the tracks
• File > Export > Multitrack Mixdown > Entire Session.....MP3 Audio

If you need more help with Audition, here is the Adobe resource with tutorials:

## 6. References

• Picture of Sine wave from: Stapel, Elizabeth. "Graphing Trigonometric Functions." Purplemath. Available from
http://www.purplemath.com/modules/grphtrig.htm. Accessed 09 July 2012
• Python Code and Concepts from: Computing and Programming in Python, a Multimedia Approach, by Mark J. Guzdial and Barbara Ericson (Chapters 6 and 7)

## 7. Exercise

Record a short poem, nursery rhyme, or story. Using Audition, add 3 additional sound recordings to tell your story.

1. A heading for Lab 5 and a brief description of what tool was used and what you did (ie. for this lab, it might be something like  Lab 5: Audition)
2. One image of your final Audition work environment with all the layers(use Command-Shift-4 and space on a mac to take a snapshop of your Photoshop window)
4. A learning journal entry which might contain any or all of the following: a description of what you've learned, challenges faced, any YouTube videos or tutorials that you found useful, any credits for content that you got from "open source", and anything that you might want to remember about what you've done for the future.

### 7.2 Mark Distribution

• Lab 1 through 11 will be marked based on:
• learning journal in Adobe Spark (3 marks)
• this mark will be based on the description of what has been learned, any problems encountered, and solutions found
• if nothing (or barely anything) is indicated, then the mark will be zero or one
• if there is a good documention on learning, then the mark will be two or three
• exercise submission (5 marks)
• 3 marks will be given for following the exercise precisely
• to get 4 or 5 marks, the submission will have to use innovation and substitutions of bits and pieces (outside of the box of what was taught). If you get a 5, that means that you have WOW'ed me

• The punctual attendance mark works differently from other labs (it is a subtraction system if you do not attend the labs):
• 1 late/non-attendance is forgiven
• 2 lates/non-attendances will result in a 10% loss of your total lab grade
• 3 lates/non-attendances will result in a 25% loss of your total lab grade
• 4 lates/non-attendances will result in a 40% loss of your total lab grade
• 5 lates/non-attendances will result in a mark of zero for the lab