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Last month I introduced the dark-sounding minor-seven flat-five (m7b5) chord and demonstrated a few ways guitarists can incorporate it into the writing of thrash-metal rhythm-guitar riffs and ideas.
This month, I'd like to continue with more examples of how to use this unusual sound in a variety of cool, effective ways within thrash metal.
To review, let's start with a normal minor-seven chord, such as the Cm7 shown in FIGURE 1. Play each note individually, starting with the root, C, then the fifth, G, the minor, of "flat," seventh, (b7), Bb, and then the minor, or "flat," third (b3), Eb. Then strum the entire chord, making sure all the notes ring clearly. Let's now lower, or "flat," the fifth, G, (D string, fifth fret), down one half step, to F# (fourth fret). The result is Cm7b5, as shown in FIGURE 2.
Again, pick out the notes individually, then strum them together. The intervallic structure of this chord voicing is, low to high: root (C), b5 (Gb), f7 (Bb), f3 (Eb). The sound of the b5 creates a really cool kind of tension that is fun to explore within metal music.