Hi Lee. Am I correct in assuming that if you start on 5th string, 3rd fret (c, thus the root) and go to 6th string, 3rd fret (g) that is the perfect 5th; and 4th string, 3rd fret (f) is perfect 5th? {or did I swap 4th and 5th? – do I have it backwards?)
in any event, if what I am suggesting is right, then that formula show work up and down the neck as well as vertically, correct? Expect at the b string. Still trying to see how that works.
Do you have a set of charts showing how 4ths and 5ths stack for all 12 keys (or even one key? – as long as this is a movable type “shape” for lack of a better word.
i get great info from your site and I do appreciate it.
jeff baily
blanca, colorado
You’re mostly right … the F will be a 4th (up from C), not a fifth.
It can be confusing because they can be inverted with direction. I.e., C to F ascending is a fourth interval. Descending, it’s a fifth interval. When we say things like “the fourth of C” we are referring to its ascending scale position, e.g C1, D2, E3, F4, 5G, 6A, 7B.
The 4th of C is F. (C major scale = C1, D2, E3, F4, G5, A6, B7)
The 5th of F is C. (F major = F1, G2, A3, Bb4, C5, D6, E7)
The intervallic distance doesn’t change though, so there will always be a perfect fifth (7 semitones) between C and F in either direction.
The problem with this stuff is there isn’t often enough distinction. I sometimes use the term “Scale Formula” rather than “Scale Intervals” because most of the time when we say things like 3rd, 4th, 5th etc we’re usually talking about the ascending numeric position of the scale. Calling it an interval, although it makes sense, can lead to this kind of confusion.
I don’t think I have charts on the website, not that I can think of but you can use the scale finder to show the fretboard with scale notes and (formula) intervals.
https://www.guitar-chords.org.uk/chord-calc/scale-note-finder.php
I thank you! My feeble brain just may be starting to get it.