Palm mute

A palm mute is done by resting the edge of your picking-hand palm right in front of the bridge while playing — not muting the string completely, just enough to shorten its ring. The harder the palm presses, the more muffled and "chugging" the sound; the lighter the touch, the more open the note stays.

Why it's closer to a dial than an on/off switch

Despite the name, palm muting isn't a binary effect: the amount of pressure genuinely changes the tone, from a felted, almost percussive low end to a barely-muffled note. That fine control is what makes Guitarshelf's metal gallop riff recognizable — without palm muting, the exact same frets would sound much closer to a plain rock riff.

The move is isolated in the technique sheet alternate picking with palm mute before being combined into a full riff.