Week 1 - Class 1
In this class, we are going to learn about frequency, and we also are going to dip our toes into the software that we will be using in this class: Adobe Audition.
Sound is created by the compression and rarefaction of air, and the perception of that air by our ears (and brains). Watching a speaker cone at a slow speed (low note) will show the process of creating these air waves. When we work with audio on a computer screen, we see a 'waveform', but this is just another way of visualizing the compression and decompression of the air - or the movement of the speaker cone.
Learning about frequencies is the most important thing we can do to understand audio, so we are going to watch a video that shows us some information about the frequency content of audio.
We can play with audio frequencies by using an audio generator (often called an 'oscillator'). As you know, I'm a Max Guy, so I've built some 'fixtures' that we can use to play with audio. You can try out my Oscillator Fixture at this link.
If we open up Audition and pick some arbitrary sound, we can see that there is seldom 'pure' tones with pure frequencies:
If you want to change the frequency of a sound, you have to use a 'pitch change' tool to perform the task. This is in Audition, and it is called the 'Stretch and Pitch' effect:
One thing to understand about working with these effects: you can perform any function on either the whole file, or just part of the file.
Let's grab some audio from an online sound repository FreeSound.org. Download some files, open them in Audition, figure out the interface, and pitch them wildly in different directions. If you need help to understand Audition, there are many tutorials on Adobe.com, YouTube and other tutorial sites.
In-Class Assignment Due Today1. Pick out 2 files from FreeSound (or other sites), use the 'Stretch and Pitch' effect to create wild versions of them. Have each file be less than 15 seconds. Save them and email them to me at "firstname.lastname@example.org".
Assignment Due for Wednesday:
1. Pick out 10 files from FreeSound (or other sites), use the 'Stretch and Pitch' effect to create wild versions of them. Store them on your thumb drive and bring them to class (you will be passing them off to me).
2. Find and watch three (3) videos about audio frequencies, Adobe Audition, or something else that might relate to this class' work. Email me three links (email@example.com), and tell me which one was most useful - and why!
Week 1 - Class 2
Pitch is primarily a cultural creation. The concept of an octave - the increase of a tone while maintaining its context - has some physics behind it: it is a doubling of the frequency. However, divisions of an octave is a cultural construct; Western music is focused on dividing an octave into 12 notes, but other cultures have different divisions. In this class we are going to embrace the 12 note Western scale (C, C#, D, D#, E, F, F#, G, G#, A, A#, B), but that shouldn't prevent you from experimenting with other options.
The connection between frequency and pitch is described in the following chart:
We can experience the frequency-to-pitch change (and the exponential move) with the following Max patch: download this.
These pitches are determined by 'semi-tone' moves, which are moves along the 12-tone list. So, we see that moves are either whole tones (moving two steps on the scale) or a half tone (moving one step).
Once you have access to the 12-note scale, you can start making 'tonal' music. However, if you use all 12 tones, you won't be following typical musical devices. Standard music places music into 'keys', which are a grouping of notes that are used to create standard melodies and chord form.
Scales generally have seven notes, then repeat at the octave. Here is the way that scales are divided into keys:
If you make melodies (musical 'lines') using these 7-note scales, you will be using a 'Major' key - which tends to sound positive/happy. Much modern music uses 'Minor' keys, which have a dark/sad sound. Luckily, you don't really have to change anything. A Minor scale is just a Major scale, but you start at the 6th step.
So, for example, if you take the C Major scale (C, D, E, F, G, A, B, C) and instead start at the A note (A, B, C, D, E, F, G, A), you are working with an A Minor scale. Same notes, different sound! You can emphasize whether you are C Major or A Minor based on the notes that you emphasize: the first, third and fifth element of the scale tend to make things clear.
So how do we work with scales when we are just doing a virtual "cut and paste"? Well, we can start with a tone, then use some of the information from the charts above, then use some Audition tricks to make the tones we want. The key is to create many copies of a segment, use the 'Stretch and Pitch' effect to alter the pitch based on the scale structure (remembering that semitones = steps on the 12-note range), then combining them into a melody.
In reality, we will want to work within a single key, and use some of the 'Stretch and Pitch' functions to help us take an arbitrary sound and adjust it to a key. To simplify all of the above charts, we will refer to this chart for our in-class work:
Follow along with me while we use a Freesound.org sound to create a little melody...
Create three 10-second melodies that include at least five different tones. Use the looping transport to make sure that it sounds good as a little 'tune'. Turn in these melodies before you leave for the evening.
Assignment Due for Next Monday:
1. Using one of the sounds you created, make a melody that is between 60 and 90 seconds long. Make sure that you bring it to class on your thumb drive - I will be collecting this.
2. Find and view two (or more) videos about creating chords. How does this relate to the scale information we've discussed. How do you think you could use this within the Audition software? Send me links to the videos, and try to explain how you might make chords using the basic Audition software.