visualizing diagonal lay of M3/m7 intervals

[notyalcer]

Just an observation I wanted to share. I started to see the M3 and m7 intervals for a dom7th chord as a repeating diagonal line across the fretboard. Here are the diagrams for roots on the 6th and 5th strings. There is a shift/gap on the B string for root on the 6th string; for root on the 5th its perfectly diagonal:

–––|–––|–R–|–––|–––|–––|–3–|
–––|–––|–––|–––|–––|–7–|–––|
–––|–––|–––|–3–|–––|–––|–––|
–––|–––|–7–|–––|–R–|–––|–––|
–––|–3–|–––|–––|–––|–––|–––|
–7–|–––|–R–|–––|–––|–––|–––|

–––|–––|–––|–––|–––|–7–|–––|
–––|–––|–––|–––|–3–|–––|–––|
–––|–––|–––|–7–|–––|–R–|–––|
–––|–––|–3–|–––|–––|–––|–––|
–––|–7–|–––|–R–|–––|–––|–––|
–3–|–––|–––|–––|–––|–––|–––|

For the Major 7th the diagonal lines would shift up a fret. For Min7th chords it loses its diagonal shape.

[decay-o-caster]

I think your root on the 5th fret diagonal gets broken at the B string as well - that's a minor 3rd you've put in there.

Which actually makes it easier - there are no exceptions - just shift on the B string.

[Sadhaka]

I think your root on the 5th fret diagonal gets broken at the B string as well - that's a minor 3rd you've put in there...

Yeah, that's correct... And the seventh on the first string is a fret up as well. If we were to consider this a D7 chord, then you want the 3rd to be f# and the 7th to be C natural.

F# seventh fret of the second string, C Nat 8th fret of the first string.

I assume the OP made a typo....

[rockinrob]

Just an observation I wanted to share. I started to see the M3 and m7 intervals for a dom7th chord as a repeating diagonal line across the fretboard. Here are the diagrams for roots on the 6th and 5th strings. There is a shift/gap on the B string for root on the 6th string; for root on the 5th its perfectly diagonal:

–––|–––|–R–|–––|–––|–––|–3–|
–––|–––|–––|–––|–––|–7–|–––|
–––|–––|–––|–3–|–––|–––|–––|
–––|–––|–7–|–––|–R–|–––|–––|
–––|–3–|–––|–––|–––|–––|–––|
–7–|–––|–R–|–––|–––|–––|–––|

–––|–––|–––|–––|–––|–7–|–––|
–––|–––|–––|–––|–3–|–––|–––|
–––|–––|–––|–7–|–––|–R–|–––|
–––|–––|–3–|–––|–––|–––|–––|
–––|–7–|–––|–R–|–––|–––|–––|
–3–|–––|–––|–––|–––|–––|–––|

For the Major 7th the diagonal lines would shift up a fret. For Min7th chords it loses its diagonal shape.


That is an important thing to understand (besides the mistakes which have been pointed out). Along with it, it is important to understand that what you have there is an interval of a b5th. It's this b5th interval within a 7th chord that gives it such a strong sound. Seeing this "diagonal line" can not just help with 7th chords, but also with diminished ideas, augmented ideas, or anything that has that b5 interval in it.

One thing that really helped me to better visualize the fretbaord is to see things in octaves. So:


–––|–––|–-–|–––|–––|–––|–-–|
–––|–––|–––|–––|–––|–-–|–––|
–––|–––|–––|–-–|–––|–––|–––|
–––|–––|–-–|–––|–R–|–––|–––|
–––|–-–|–––|–––|–––|–––|–––|
–-–|–––|–R–|–––|–––|–––|–––|


That's an octave. Now add a 5th:

–––|–––|–-–|–––|–––|–––|–-–|
–––|–––|–––|–––|–––|–-–|–––|
–––|–––|–––|–-–|–––|–––|–––|
–––|–––|–-–|–––|–R–|–––|–––|
–––|–-–|–––|–––|–5–|–––|–––|
–-–|–––|–R–|–––|–––|–––|–––|

Just like your diaganal line, this pattern will repeat (except for the B string, of course). If you know where the 5th is (which is very easy to remember) then it's easy to know where the 4th is. From there the 3rd, or 6th, or 7th, etc. Next octave shape is this:

–––|–––|–-–|–––|–––|–––|–-–|
–––|–––|–––|–––|–––|–-–|–––|
–R–|–––|–––|–-–|–––|–––|–––|
–––|–––|–-–|–––|–-–|–––|–––|
–––|–-–|–––|–––|–––|–––|–––|
–-–|–––|–-–|–R–|–––|–––|–––|

In which case the 5th is here:

–––|–––|–-–|–––|–––|–––|–-–|
–––|–––|–––|–––|–––|–-–|–––|
–R–|–––|–––|–-–|–––|–––|–––|
–5–|–––|–-–|–––|–-–|–––|–––|
–––|–-–|–––|–––|–––|–––|–––|
–-–|–––|–-–|–R–|–-–|–––|–––|

When you understand these things you realize there's only so many ways to build a chord if you're starting with the root on a lower string. Things like CAGED then start to make a lot of sense.

[notyalcer]

I screwed up my second diagram...but seeing these shapes is starting to become more natural as I work on them.