The Art of Solo Flatpicking
When people use the term flatpicking to denote a musical style, they’re usually referring to the furious fiddle tunes and hot instrumentals spun out by the likes of Doc Watson, Tony Rice, and David Grier. But lead guitar in a bluegrass or old-time setting really began back in the 1920s with Maybelle Carter’s melodic song-based guitar solos with the Carter Family. Carter created her self-contained sound by playing the melody to songs while accompanying herself by strumming in the keys of C or G. Although flatpicking tends to be a social sport, some players (Clarence White, Beppe Gambetta, David Grier, and others) have expanded on Carter’s example by accompanying songs and fiddle tunes with open bass strings.
The preferred flatpicking keys of G, D, and C, however, don’t provide much in the way of open bass strings, except for the fourth (D) string, which is really not all that low and often ends up being used as a melody note in the key of D. One easy way to get a full bass sound that will allow you to accompany yourself is by lowering your sixth string from E to D, which puts you in dropped-D tuning (D A D G B E). Most bluegrass players have shied away from open tunings, primarily because the string tension of standard tuning seems to produce the right timbre—a nice tight snap with a full rich sound. But this is a small modification, and if you use medium-gauge strings (or at least a medium sixth string), your guitar will retain most of the timbre of standard tuning, and it’s also relatively easy to switch back and forth between dropped D and standard. The advantage of dropped-D tuning becomes obvious once you strum all six strings of an open D chord—finger the D as you normally would but this time add the lower strings.
Try playing a simple D-major scale in open position (Example 1) and then slowly strumming the bass strings as you play each note of the scale (Example 2). Some notes will sound better than others, but you get the idea. Now let’s get a little more precise and simply play one bass note to accompany each note of the scale (Example 3).
Excerpted from Bluegrass Guitar Essentials