Brutality Meter

The brutality percentage is a weighted sum of six sub-scores between 0 and 100. Tremolo weighs 25 percent, chugs 20, dissonance 20, speed 10 and low end 10. Melody weighs 15 percent but counts in reverse: more melody gives lower brutality.

The number is unscientific on purpose. It is consistent, though: a riff always gets the same score, because everything is arithmetic on the notes and no randomness is involved. The score is grouped into five levels with limits at 20, 40, 60 and 80.

Each sub-score is scaled against a ceiling. When the ceiling is reached, the score is 100.

• Tremolo: the share of the riff that is tremolo picked or made of at least four sixteenth notes in a row on the same note. Half of the riff gives 100.
• Chugs: the share of notes that are palm mutes, or short repeated notes on the two lowest strings. 60 percent gives 100.
• Dissonance: the share of jumps that are a semitone, a tritone or a major seventh, plus dissonant notes between melody and harmony. 35 percent gives 100. Repeated notes do not count.
• Speed: number of notes per second. Twelve per second gives 100.
• Low end: how low the riff sits on average. C2 or lower gives 100 and E4 or higher gives 0.
• Melody: half depends on how many different notes are used (five or more is full) and half on the share of jumps that are soft steps, from a second to a fifth and a sixth.

A chug is a short, palm-muted hit on a low string, often repeated on the same note. Tremolo picking is very fast alternate picking on a single note. A tritone is the interval of six semitones, long known as the devil's interval and often used in heavy metal because it grinds.

Use the meter to compare two versions of the same riff. Swap a few notes for neighbouring semitones, add palm muting or lower the tuning, and see which sub-scores move.