A close look at how triads are constructed, as well as a look at how triads are built on each degree of the major scale.
Building a triad
Take a major scale and play every other note: one, miss two, play three, miss four, play five. Root, 3rd, 5th – that's a triad, and it's always the 3rd that tells you whether it's major or minor. Another way to see it: triads are built by stacking 3rds. A major 3rd with a minor 3rd on top gives you a major triad; flatten the 3rd and the stack flips (minor 3rd below, major 3rd above) for a minor triad. Flatten the 5th as well and you get the diminished triad – two minor 3rds, with that restless tritone between root and flat 5. Sharpen the 5th instead and two major 3rds make the augmented triad. Four building blocks: major, minor, diminished, augmented.
Open and closed positions
Play the three notes packed as tightly as possible and you have a closed triad; lift the 3rd up an octave (making it a 10th) and the chord opens right up – the open voicing that sounds so good on bass, because the wider spacing keeps the low end clear. Played together they're a chord; played one note at a time they're an arpeggio, which is where bass players live most of the time.
Triads on every degree
Build a triad on each degree of the major scale and a pattern falls out: chords 1, 4 and 5 are major, 2, 3 and 6 are minor, and 7 is diminished. That one pattern explains an enormous amount of the music you already know – including the famous four-chord (1–5–6–4) progression that the comedy band Axis of Awesome proved runs through dozens of hit songs.
Hear the same shapes put to work in Triads and Arpeggios on Bass: Mozart to Madness, or see them walking through a blues in Walking Bass Lines the Easy Way.
This is just a small dip into the exciting world of bass and music theory. If you want to take your playing and knowledge to the next level, whether you're just starting out, or experienced and looking to fill in the blanks, why not book a lesson today?