Palm muting is the most consequential thing a metal guitarist does with the hand that is not choosing the notes, and the entire technique amounts to one square inch of skin put down on six strings in exactly the right place.
Run a garden hose at full pressure and the water slops out of it in a fat, shapeless column that floods the path, drowns the bed beside it and reaches nothing at all past four feet; lay a thumb half across the mouth of the same hose, at the same pressure, and what leaves is a jet hard enough to strip moss off a wall. Nothing has been added. Something has been blocked, and the blocking is where the force came from.
The fleshy pad that takes the weight when somebody leans on a table, the one below the little finger, is what the anatomy books call the hypothenar eminence, and where it lands settles everything that follows: the pitch, the length of the note, how much of the amplifier's roar survives and whether a riff arrives as a wall or as a row of separate blows. A guitarist learns the spot in a week. He spends thirty years refining it by two millimetres at a time.
The rhythm guitarist who made the closed low string the spine of a whole band's sound, and made a virtue of how much it hurts to keep it there, is James Hetfield of Metallica. Where the technique sits among the genre's other working parts, the bare fifth, the tritone, the gallop and the harmony lead, is given in the longer account. The mute deserves its own look, because it is the one device in the kit that works by taking sound away.
Where palm muting actually puts the hand
The landing zone is the strip of string in front of the bridge saddles, on the tailpiece side of them, and it is narrower than most beginners expect. Sit the pad right against the saddles and the mute is barely there, a slight shortening of the ring. Slide it a centimetre towards the neck and the note loses its pitch and turns into a dead knock. Everything useful lives in the two or three centimetres between those two failures.
Pressure is the second variable and the one that ruins more recordings. Too little and the string sings on underneath the next three notes. Too much and the fundamental is strangled out of it, leaving a percussive click with no note in it at all, which is a sound with exactly one use and no others. The hand has to be heavy enough to quench the ring and light enough to leave the pitch standing.
The notation is the simplest in the guitar repertoire. Two letters, P.M., are printed above the stave or the tablature, and a dotted line runs out from them for as long as the hand stays down, which means a metal transcription can be read as a map of a hand rising and falling before a single pitch has been looked at. That map is usually the song.
What the mute does to a distorted string
Distortion is a machine for making everything last. It clips the waveform, throws off harmonics the string never produced on its own and holds notes up long after the pick has gone, which is exactly what a solo wants and exactly what a fast riff cannot survive. Left open, eight notes on the bottom string arrive on top of one another and the riff loses its shape.
Shout in a bare stone room and the shout comes back at you three times, thickens into porridge and buries the next word out of your mouth. Hang that same room with wet blankets and the shout lands once, square, and dies where it hit. The picking hand is the blanket, hung and taken away again several times a second.
Every other school of guitar playing is about making a note last. This one pays a man to decide, two hundred times a minute, exactly when to end one.
Julien Vasseur, KaosMetal
What the listener then hears as speed is mostly the silence. A muted stroke is attack, a very short body and nothing after it, so the gaps between strokes are audible as gaps, and the ear counts them and reads the count as velocity. A modern rhythm track puts a noise gate behind the amplifier to keep those gaps genuinely silent, and the tighter the gate is set, the harder the hand has to work to avoid being cut off mid note.
The silence between the strokes is not a gap in the riff. Most of the time it is the riff.
Where the technique came from
It arrived in heavy metal fully formed, because Nashville's session players had been muting strings for twenty years before anyone plugged in a metal amplifier. The most recorded of them, credited with the sound the trade nicknamed tic tac, was Harold Bradley, who doubled a bass line on a six string Danelectro with the strings muted so the note knocked instead of ringing.
The Californian guitarist who took the same hand position, pointed it at a room full of teenagers and built a whole coastal style on it was Dick Dale, whose muted, tremolo picked low strings are the sound a listener now files instantly as surf. None of those players wanted weight. They wanted a short note and a clean floor under a singer.
Heavy metal took the hand position and put a hundred watts behind it, and the moment it did, palm muting stopped being an effect and became the structure. A riff is now built out of the switch between the muted state and the open one, and the open chord only lands because eight closed strokes came before it and taught the ear what closed sounds like.
The records built on the hand coming off
The exercise every rhythm guitarist is eventually set is "Creeping Death", the Metallica song from Ride the Lightning, released on Megaforce in July 1984, and it is an exercise in attrition as much as in rhythm: the main figure is a stream of muted strokes taken with the plectrum going one way only, which sounds identical for the first thirty seconds and then starts telling the truth about how fit the player is. Alternate picking would be easier. It would also sound wrong, and every player who has tried it knows why.
The Texan guitarist who built an entire groove out of the instant the hand leaves the strings was Darrell Abbott of Pantera, and on "Walk", from Vulgar Display of Power on Atco in 1992, the riff is a clamped, marching figure that opens for a fraction of a beat and shuts again, so the swagger of the song is not in the notes at all but in the timing of a release. Take the mute off and the riff is ordinary. That is the measure of it.
The Bay Area band whose debut made the muted low string the whole architecture of a song was Machine Head, and "Davidian", the opening track of Burn My Eyes, released on Roadrunner in August 1994, holds the mute across almost every bar and gets its violence from three or four places where Robb Flynn lets it go. The releases are the events. Everything else is the run up to them.
Two guitars playing the same muted part have to land to machine tolerance or the doubled track smears, which is why a rhythm section that sounds effortless on record generally took the longest to cut, and why the same discipline governs the twin guitar harmonies laid over the top of it. Slack strings make it harder again. A tuning dropped two whole tones leaves the string flopping under the pad, and the hand has to be milled back down to a lighter, more exact touch to keep the pitch alive.
Faults are easy to hear once they are named. A hand creeping towards the neck across a long passage turns the riff to mud by the last bar. A hand that lifts slightly on the upstroke gives every second note a longer tail and puts a limp in the rhythm. A wrist locked rigid lasts four minutes and then stops working, which is why the technique is taught from the forearm and the elbow, not from the fingers. It is a labouring job, and the hands of the men who do it look like it.
