Thirds are a lot more useful as double stops than seconds, and obviously they’re key building blocks of most chords. Luckily, no stretching or string skipping is required to grab major or minor thirds across the neck. They work nicely hammered on to/from fourths or from major seconds as well.
This may be the least useful individual diagram I ever post, but for the sake of completeness, I am starting my run through of intervals with major/minor 2nds. I worked through Truefire’s Interval Insights course, and I now feel even more confident that knowing where to grab all of the intervals on the neck is a worthwhile skill to have. I can’t demonstrate how to use them in context here, as Rich does, but it should be pretty simple to lay out the locations of each set to refer to for your own experiments.
Seconds are neither particularly consonant nor comfortable to grab. I kept stretches to a three fret minimum in this diagram, as going out of your way to grab either of these doesn’t seem necessary.
Diving back to triads in all positions. I don’t naturally grab these triads up the neck, but now is as good a time as any to start.
On to the top three strings. I’ve personally never spent enough time on the shapes on these strings, so this is a useful learning exercise, and hopefully sharing these proves helpful more broadly. I’ve certainly never noticed that barring the top three strings gives you a major sixth or that you have a useful, easy sus2 in most pentatonic boxes.
It’s time to move onto the triads on the first three strings. I’ve neglected learning these for far too long personally, so a good study of the major triads on 1/2/3 is warranted. It’s also probably time to start looking at the minor triads on both sets, which are easy to get to from their major counterparts.
One last useful triad on strings 2/3/4. We all probably know this one, though I’ve never looked for the extensions until now. Knowing how to alter this simple bar is a great tool.
This one shows up everywhere as well, and it’s very helpful to know your options when looking for embellishments.