Lesson 01
Everything in this course emerges from one thing. Before any scales or chords, before any names — one sound, one vibration, one frequency.
What is a frequency?
Let's start from a single sound. Not a chord or a melody. Just a simple click.
Let's play this click one time per second. This is too slow to be heard as a pitch. This is just heard as rhythm.
At around twenty cycles per second we stop hearing clicks and start hearing a tone. A pitch. A note.
One hundred cycles per second gives us a clear tone. Let's call this our fundamental frequency. We could have chosen to stop at any frequency, but for now let's use 100Hz, and build from there.
There is a whole spectrum of notes, low pitched through high pitched. Humans can hear approximately between 20Hz and 20,000Hz.
The harmonic series
×1 · 100 Hz
Click the string
Also called the “root” note. The whole string moving as one piece. This is the note we measure everything else against.
We could keep going up forever
Let’s pause for a closer look at the first four harmonics.
So, out of the first four notes in the harmonic series, only one is a genuinely new note.
Harmonic 3
300Hz blends well into the fundamental, but isn't a higher or lower version of it. It sits at a specific distance (or interval) from the root note. This important interval is called the fifth.
Why "fifth"? We'll get into to that later. The name is arbitrary. The relationship is not.
Harmonics 1, 2, 4, 8
Each doubling lifts the fundamental frequency by one octave: ×2 is one octave above where we started at 200Hz, ×4 is two octaves up, ×8 is three. Keep doubling or halving the fundamental frequency and we find the closest possible notes to where we started. Even though these are very different pitches, they're all as closely related as notes can be. We say they're all the same note, but in different octaves.
Click any marked key
Three octaves of the same note, here visualized on a piano keyboard. We could keep doubling or halving and find more of the same note.
Not with scales or chords. With one new note.
Vocabulary
The hertz is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. More on hertz.
A distance between two notes. The first two intervals defined by the relationships in the harmonic series are the octave and the fifth. We’ll learn more later.