Circle of 5ths / 4ths showing all the notes of each key as radial spokes:
Monday, June 23, 2025
The Circle
Friday, May 2, 2025
The Speed of Pitch
What we call "octaves' are the phenomenon of a 2:1 frequency ratio. Our perception of octaves as "the same note" seems to be a deeply embedded sense. No one questions the practice of giving two different notes the same name when they are one octave, two octaves, three octaves or more apart from each other.
Why is this?
What is it about this 2:1 ratio that we sense as "the same"?
Consider the effect of clapping at a steady speed, then doubling the speed of clapping. Or have another person clap along with you but at double the speed and stay in sync.
You'll notice that the claps will perfectly align every other beat, so that the lower speed clap is effectively embedded in the faster one. The ratio of the frequency of your clapping is the same as an octave. This provides a clue as to the reason octaves are perceived as the same.
In the ear, sound is processed by setting in motion some 15,000 tiny specialized hair cells, each of which has between 50 and 300 filaments projecting from it, called stereocilia. These hairs are contained in a fluid filled spiral shaped structure called the cochlea. The hairs and the stereocilia in each ear resonate with specific frequencies and transmit that information to the auditory cortex of the brain which has specialized neurons for each frequency and range of frequencies. So your brain is always sensing the frequencies of every sound and is able to recognize the ratios between those freq
uencies.
Exactly how the brain can calculate the precise frequency ratios between all the pitches we hear is quite complex and still somewhat mysterious, but it is probably connected to the brain's ability to sense time as sequential events based on it's own brainwave frequencies and the embedding of resonations in its neural network. Regardless of the precise mechanism, it's clear that we are very good at perceiving the ratios between notes regardless of their absolute pitch.
In other words; if you hear a melody in one key, and then the same melody in another key, you recognize it as "the same" because you recognize the ratios between the frequencies of every note in the melody, rather than relying only on the absolute pitches of the individual notes. The melody of the song Happy Birthday in the key of C would be:
Saturday, October 26, 2024
Modal Arpeggios — Arpeggiometry
Each of these arpeggio patterns encompasses all six strings and include all the notes of any diatonic key spanning two octaves.
They are ordered in 5ths:
II, VI, III, VII, IV, I, V.
Try playing each of them rooted on the same fret position and notice the difference in fingering as you go from one to the next.
Wednesday, March 29, 2023
More Modal Madness Galore!
Before you venture into this ... please study the previous post:
https://fretography.blogspot.com/2023/03/diatonic-symmetry-galore.html
Now ... where were we?
Ok ... we're making connections between modes and keys across the diatonic system. Modes do not only exist in separate keys with walls around them. The cross key relationships we find in so much music have their own logic, grammar and flow.
The character of each mode becomes a pathway from one musical idea to another. We sense when the key has changed, and it is modality that provides the framework of coherence of the harmonic and melodic threads.
Since Dorian mode is diatonically central, lets see how it connects to the seven keys drawn from its traverse of natural tone finals ...
Wednesday, March 15, 2023
Modal Symmetry Galore
The symmetry built into the Diatonic system has many manifestations. One of the most compelling is the phenomenon of modal common tones.
Deep Symmetry
The modes form palindromic interval groupings ...
Ionian and Phrygian,
Locrian and Lydian,
Aeolian and Mixolydian,
... and Dorian mode ...
The intervals within each mode are part of the overarching Diatonic symmetry. Study the interval structure of the modes ... notice the palindromic pairings:
Common Tones connect seven keys in a modal continuum ...
Modal Common Tones
When the notes of Major scale (Ionian mode) each become the tonic of a new key there is but one note common to them all. In the Key of C are the notes C D E F G A B ... the scale will include the complete octave — C D E F G A B C.
Make each of these natural tones the Tonic, and you have seven keys, and within each of them is the note 'E' ... the III of the original key. There will be no other note to find a place in all seven keys.
That's interesting enough, but there's more!
Do this with all of the seven Modes, and you'll find the correlation between Mode's interval symmetry and the Common Tone Counterpart groupings.
Common Tone Counterparts are those notes that link the diatonic symmetry due to their corresponding key degrees.
Just as Ionian and Phrygian are a palindromic pair, the notes C and E are positioned symmetrically around the central note of the key: D ... as are B and F, as well as A and G ... and their respective modes.
These images show the common tones in each mode. In each case — within seven keys which have Natural tones as their tonics:
...
Friday, April 15, 2022
Pentatonic/Diatonic Relationships
When you think of pentatonic scales do you connect them to the diatonic key? Do you think of a major pentatonic scales as being rooted in the tonic of the key?
For instance — most of us might believe the following; C major pentatonic 'belongs' to the key of C major ... G major pentatonic 'belongs' to the key of G major ... etc ... So that each major pentatonic scale is matched to a single major key. And of course, the relative minor pentatonic is matched to the relative minor of each key, so A minor pentatonic 'belongs' to the key of A minor, and so on.
You may also understand that when playing blues based music you can use an A minor pentatonic scale to riff on an A dominant7 chord, and also use an A major pentatonic with that same chord, and that doing so falls outside standard diatonic theory.
But what about fully exploring diatonic possibilities of the pentatonic scale? Are you aware that each diatonic key contains not one, but three pentatonic scales, each with the same interval structure?
The key of C includes not only the C major/A minor pentatonic scales, but also G major/E minor and F major/D minor.
Here are the notes of the key of C: C D E F G A B C ...
... and here are the notes of the C major pentatonic scale: C D E G A C.
Now, here are the notes of the G major pentatonic scale: G A B D E G, and the F major pentatonic scale: F G A C D G.
Notice that G maj. pent. and F maj. pent. contain no sharps or flats. So not only is each pentatonic scale rooted in the tonic of its own key, but it is also positioned within two additional keys. To be more precise, the I, IV and V degrees of any major key will produce a pentatonic scale with the intervals Wholestep, Wholestep, Minor 3rd, Wholestep, Minor 3rd.
Below you see the notes of each scale in the key of C as they appear on the fret board. The first is C major pentatonic, followed by F major pentatonic and then G major pentatonic:
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(Zone names are based on the degrees of the diatonic major scale.) |
And the interval structure of each scale:
We'll look deeper into the applications of this in the next post.
Saturday, November 27, 2021
Nested Triad Inversions
The previous post showed Root triads in individual Zone positions forming stacks of 4ths. Here we'll look at the 1st and 2nd Inversion forms.
The 1st Inversion triads are formed by moving the root to the top (highest pitch), the 3rd is the low note and the 5th is in the middle of the triad.
In the diagram below, If we read the "I" as the note G on the 3rd fret on the 6th string:
... then the first chord in the VII Zone (reading from the bottom of the Zone) is an F# diminished. Though the II of the key is the low note, the VII of the key is the root of this triad, as the high notes in all these triads are their root notes.
The green triad in II Zone is the Tonic chord since it has the high note of "I" even though its low note is III, etc ...