When guitarists alternate pick a note at a very fast, unspecified rate, it’s called tremolo picking. The pickstrokes are not set to specific note values; instead, a player picks as fast as he can steadily maintain. This technique is particularly common in mandolin playing.
In this example, you play the open sixth string, E. When you see three slashes below a note, that’s your cue to tremolo pick. You tremolo pick for the duration of time equal to the note’s value. For example, the very first note is a quarter note, so you quickly alternate your pick during the whole beat. In the second measure you tremolo pick for two beats, and in the third measure you keep it up for the whole measure.
With tremolo picking, you may find that you settle into a fixed rhythm, like perhaps thirty‐second notes, which are twice the rate of sixteenths. You may see some scores that try to notate each and every note in a tremolo‐picked line. These things are fine, but keep in mind that, technically, tremolo picking is not a fixed rhythm and doesn’t need to be precisely picked or notated.
Next, you use tremolo picking to play a lead line, one based in the double‐harmonic minor‐scale a la Dick Dale’s “Misirlou.” Play the part without tremolo picking first; just work out the notes and on which parts of the beats they change. When you get a feel for the melody, play it by alternate picking on each note as fast as you comfortably can, and maintaining the picking motion the whole time, even as you change notes. You can apply the same idea to other strings.
With tremolo picking, you may find that in order to pick across one string as quickly as possible, you must use a hand position and picking motion that are different from what you use during normal picking. For example, you may float your picking hand rather than anchor it, and you may lock your wrist rather than alternate from it. Experiment with these things and go with whichever options work best for you.
This example is played along the first string and all the way up at the 12th position. Here you use tremolo picking on a melodic idea based on the first five degrees of the E‐major scale. Eddie Van Halen does something similar in “Eruption.” This is played at 120 BPM, but you can adjust the tempo if need be, and apply the same idea to other strings.
Eddie Van Halen doesn’t anchor his picking hand while tremolo picking. Instead, he curls his wrist and floats above the string. Some guitar players refer to this technique as “hummingbird picking” because Eddie’s hand floats and alternates rapidly, much like a hummingbird feeding at a flower. You may find this hand position useful, too, especially when tremolo picking along the first string.