Bass Emporium Newsletter - October 2008
Ed Friedland's
Bass Emporium Lesson #3: Diatonic Chord Structures
by Ed Friedland
The last two lessons have dealt with the major scale in different ways, but there are many more secrets to be learned from this ubiquitous series of tones. Lesson #2 examined the scale as it is broken up in various intervals, and there were several references to the diatonic chord structures. This month, let's go right to that information.
The definition of diatonic is: "of the scale", so what you have here are chord structures built entirely from the notes contained within the given key— in this case, C major. By building a vertical structure in thirds from every note of the major scale (using only scale tones), you get these seven diatonic chords: IMaj7, iim7, iiim7, IVMaj7, V7, vim7 and viim7b5— capital Roman numerals indicate a major chord, small numerals indicate minor. The beauty of the numerical system is that it remains the same for all major keys, making it easy to transpose the information. Knowing this sequence of chords is very important for all musicians, but for bassists that dare to venture beyond the safe haven of the root-5-octave, it's a must.
Often you'll have to learn a song by the number system: 1-6-2-5, etc. In the diatonic realm, 1 is IMaj7, 6 is vim7, 2 is iim7 and 5 is V7. Of course, not every form of music will use all four notes of a seventh chord (R-3-5-7) — country, folk, rock, among other styles rely mostly on triads— you simply leave off the 7th of each chord. Another thing worth mentioning: not all songs are strictly diatonic. It's not unusual to have a 2 chord that is major, especially in country, sometimes the 6 is major too. The point is, if you learn the diatonic stuff, you'll immediately hear if a chord is NOT diatonic. You're going to play the root first, so if the 6 chord is major, you'll know right away and adjust what you play accordingly.
Example 1 takes you up and down each diatonic arpeggio in sequence. You'll notice that you can play all the way through the V7 chord in position. This convenience comes in handy, but I encourage you to look for multiple ways to play this sequence. After the V7 chord, shift up to the 12th fret with the first finger and the remaining chords play out easily. While you can simply breeze through this example by following the tab, take the extra steps and examine the chord structures, learn the note names, and transpose it into all 12 keys.
