MUSIC THEORY Crash Course For Electronic Music - CHROMATIC TONAL SYSTEM

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CHROMATIC TONAL SYSTEM
So you have probably already noticed that when you’re looking at a piano keyboard, you have repeating clusters of white and black keys. For example, we can see that if we hover our cursor over this key, our MIDDLE C, on the left-hand side of the piano roll, it’ll tell us that the note name is C3. If I put my cursor up to the similar-looking white key above the C3, we can see that Ableton is calling this note C4. What does this mean!? Well these two notes, and this one, and this one and this one, and so on, are all the same note but separated by what’s called, an OCTAVE. An octave is determined by a doubling or halving of a frequency of a pitch. For example, if we halved the frequency of our middle C by dividing 256 by 2, we’d find the number 128. So if I’m not telling you lies, then the frequency of C2 should be 128Hz. Let’s find out if you can trust me! I’ll add an instrument device and spectrum analyzer to this track so that we can confirm that this note, C3, is in fact producing 256 Hz. Yep! I’ve placed my cursor over the transient, or peak of this harmonic in the spectrum analyzer, and down in the left corner of the display, I can see that the pitch is 256Hz. Yay! Okay, so what is the frequency of C2?, I’ll quickly lower the MIDI note from C3 to C2 by selecting the note, holding shift, and pressing the down arrow on my keyboard. That shortcut will work for both Macs and PCs. Okay, let’s hit play and see if this pitch is in fact sitting at half the frequency of C3, we’re looking for 128Hz.
Let’s think about octaves and pitches in a slightly different way. Let’s visualize a vibrating string, like on a guitar. The pitch of a string is determined by the frequency of the vibration, which is in turn determined by the length of the string. The longer the string, the lower the pitch. The shorter the string, the higher the pitch. For example, if you pluck a string that is one foot long, it will vibrate at a lower frequency than a string that is only six inches long. The relationship between the length of a string and the pitch of the note it produces is known as the harmonic series. The harmonic series is a set of pitches that are related to each other by whole-number ratios. For example, if one string vibrates at a frequency of 440 Hz, the next string in the series will vibrate at 880 Hz (two times 440 Hz), the next string will vibrate at 1320 Hz (three times 440 Hz), and so on. So if the full length of a vibrating string produces a frequency of 256Hz, if we put our finger on the middle fret of the guitar neck, halving the length of that string, guess what? The string begins to vibrate at double the frequency, exactly one octave higher than the full length.
Wowza. So you might already be connecting the dots on how the next part of this progression goes. Basically, someone down the line decided to continue subdividing until we were left with 12 divisions of a single vibrating string. These are the 12 pitches in a chromatic scale. For example, the C chromatic scale would start on C, and then would include C#, D, D#, E, F, F#, G, G#, A, A#, B, and C. This is tuning system is called Equal Temperament and can be defined as a system of tuning in which the octave is divided into a number of equal steps or intervals. Each step is called a semitone and in a 12-equal temperament, there are 12 semitones in an octave. This is the most common tuning system used in modern Western music, and although there are other ways to get nerdy about tuning, for the context of this course we won’t be getting into other tonal systems. Once you feel like you’ve grasped music theory fundamentals though, I definitely recommend taking a deep dive into all of the obscure and wonderful tonal systems.
Just so you know the black keys on a piano can be called sharps or flats depending on the musical scale they reside in. This course is aimed toward computer musicians so this information isn’t going to be quite as relevant for you as it may be for someone planning to read musical notation on a staff, however, the language is the same and it’ll be important for you to know what these black keys are called. If we look at the note above A, it can be called A# it could also be called Bb. Now the main thing to remember is that a sharp increases the pitch by a semitone and a flat decrease the pitch by a semitone. So we have A, A#/Bb, B, B#/C, C#/Db, etc.
Whew! Alright, that’s the scoop on the meaning of the word Pitch, Soundwave, Frequency, and Octave. All this information you’re learning now can feel a bit abstract at first, but these are all terms we’ll be using and reinforcing a lot during this course and throughout your musical adventures. But remember that you can come back to rewatch these videos at any time to refresh your memory.
In the next video, we’ll dive into the meaning and emotional significance of intervals!

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[@Electrotranqui]

Very good explain. Thanks!

[@abletoncoach]

Thank you for the nice comment! I’m super glad you found the info useful!