[BaculumMeumEst]

Somewhat unrelated: I’m looking for a comprehensive overview of why the CAGED system works on guitar. I see lots of mechanical explanations of how to use it to play various chords down the neck, but nothing explaining the theory behind it.

[lachlan_gray]

I was super obsessed with this for a while! When you have a string instrument tuned in 4ths, there are 2D patterns that emerge which you can use to "derive" or "extrapolate" what a scale shape/pattern will look like across the whole neck

Using a 6-string bass as an example: https://bradleyfish.com/the-notes-on-the-6-string-bass-guita...

You can find a 2D pattern in the white notes (green notes in the pic) that you can use to understand how the pattern will extend from a given point. For example notice EF+BC always appear in the same 2x2 box shape. Also how those boxes repeat in a diagonal line, and how boxes are connected vertically by a "strip" of 3 notes ADG

The only difference for guitar is that you have to correct for the G/B strings which are separated by a 3rd instead of a 4th, by scooting the pattern on the B+E strings up by one fret

[pd3wb6INJxN]

CAGED is descriptive, ie it's the result of someone noticing "we all know these chord shapes, and they have some useful properties which can contribute to your fretboard knowledge". Those properties are:

- those 5 chords are the first you learn, and mechanically easy to play in open position, so you know them by heart

See this diagram (https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2F...):

- the CAGED 'order' (C then A then G etc) matches the order in which octaves of the same root appear as you go up the neck, therefore CAGED is a good way of visualising octaves (see how in the 'C-shapes' column the chords 'share' root notes when played in that order up the neck)

- each chord matches a root note position (C: top part of the neck box on the 5th string, A: bottom part of the neck box on the 5th string, etc), therefore if you're playing a scale, no matter what position you're playing it in, you can choose a CAGED chord to overlay on it and easily find the root, third, and fifths (see how in the 'C major scale' column, you can overlay each chord onto one way of playing the C major scale)

- learning these mnemonics should eventually help you 'unlock' the guitar neck, ie have an intuitive knowledge of what intervals you're playing and how to build melodic lines with them

Generally, music theory 'works' because it describes why things sound good. It's not theory that informs what sounds good, rather theory attempts to describe what sounds good and build patterns which will help theory learners, in turn, make music which sounds good.

[dizhn]

Open chord shapes are just the barre shapes but the nut becomes fret zero that's barred. Looking at it this way it's easy to see why they can be moved around the neck. The shape remains the same because the relationship of the strings and the notes on them remain the same. Like root-3rd-5th would remain the same relationship only with a different tone combination.

By the way I think the most difficult thing about CAGED is that it's way too overhyped. It promises too much (scales?) but delivers too little. (Doesn't even have minors)

[BaculumMeumEst]

I've seen a few complaints about the limitations of CAGED so I've been trying to focus on theory rather than just mindlessly learn tricks and regurgitate songs. Having a lot of fun so far.

The book I'm reading (recommended in another comment) does talk about minor forms of CAGED forms, though - pentatonic scale patterns, arpeggio patterns, and chord forms.

[dizhn]

Almost everything I've seen about CAGED is retrofits. CAGED is chord based. By definition it's only 3 notes (some repeated). Scales start from 5 and go up to 7 notes. It's a whole "draw the rest of the fucking owl" situation. Might as well learn what a scale is and consruct the arpeggios, triads, chords with guitar at hand. That's a much better learning experience.

[derekerdmann]

Take a look at Fretboard Theory by Desi Serna - it spends a lot of time on how different scales are constructed and relating different patterns and chord forms back to the underlying concepts.

[BaculumMeumEst]

Thanks, this is exactly what I needed. It's amazing how much of this information other people decided to omit.