(SPOILER ALERT: Don’t peek at the comments below if you want to figure this one out for yourself.)
And now for something completely different: Since this classic Sixties “mystery riff” is so dang easy to play, it will be presented entirely by word of mouth, and can only be revealed by assembling and solving the following series of clues. Get these two bars of classic rock history right and you should feel very satisfied!
CLUE 1: The fuzz-toned riff in question is in a modal key of E (Mixolydian), encompasses two bars, and was designed to be accompanied by a second guitar playing the three chords diagrammed in FIGURE 1.
CLUE 2: The riff is based on the two-bar rhythmic motif shown in FIGURE 2a.
CLUE 3: Though many seem to think so, the three single notes in FIGURE 2b—E (the root), F# (the 2), and G (the b3)—are not the ones used to play the riff.
CLUE 4: FIGURE 3a’s refined version of the rhythm from FIGURE 2a features three strategically placed eighth-rests and a subtle slide between eighth-notes on beat three.
CLUE 5: The three single notes illustrated in FIGURE 3b—B (the 5), C# (the 6), and D (the b7)—are indeed the correct ones used to play the riff.
CLUE 6: The bass riff is not the same as the lead guitar riff. FIGURE 4a sketches out its substantially different rhythmic framework, while FIGURE 4b provides four suggested bass notes—E (the root), F# (the 2), G (the b3), and A (the 4).
CLUE 7: Keeping all of the previous clues in mind, assemble the guitar and bass riffs by applying the following formulae:
Chords = 3 x E + 1 x A + 3 x D + 1 x A. Guitar riff = 3 x B + 1 x C# + 3 x D + 2 x C#. Bass part = 3 x E + 1 x F# + 1 x G + 3 x A + 1 x G + 1 x F#.