What is a Hammer-On?
A hammer-on is a common articulation on bass and other stringed instruments. A hammer-on produces a note, not by plucking the string, but instead by pressing down, or "hammering," an already-ringing string with a finger of the fretting hand.
For example, a player is currently playing a note on the 3rd fret of a string. The player wants to play a note on the 5th fret of the same string. Instead of pressing and plucking the 5th fret note as usual, the player presses down, or "hammers," the fifth fret with a finger of the fretting hand without plucking the string in the other hand.
The hammered note will always be a higher note (or fret) on the same string.
Why Use a Hammer-On?
A common question is what is the point of a hammer-on? Why not just pluck the note? There are two common reasons one might choose to use a hammer-on.
First, the sound of a hammer-on is different compared to a usual pluck. The tone of the hammer-on sounds brighter and more percussive. In that way, it adds tonal variety to the bassline. Or, it can make the hammered notes stand out more. As with all articulations, this is an artistic choice a player gets to make. Some basslines just wouldn't sound the same without the use of hammer-ons.
The second common reason is speed or to give your plucking hand a break. With the hammer-on, you're getting two (or more) notes for the price of a single pluck in your plucking hand. While you should be able to pluck all of the notes and not rely on hammer-ons to keep up, sometimes hammer-ons can make some basslines much easier to play. (You'll know when you're cheating.) Hammer-ons can allow for playing some much more complex basslines. For instance, it can give your plucking fingers a little more time to move to another string while you're still producing notes.
What Makes a Good Hammer-On?
The name "hammer-on" for this technique makes it sound more agressive than it really is or needs to be. Don't let the term mislead you and cause you to develop an overly-agressive hammer-on technique. If your bass is set up well (your strings aren't too high above the fretboard), the hammer-on technique can be quite gentle. You don't need a lot of force to make the hammered note ring out.
The Three Keys to Good Hammer-Ons
There are three keys to getting a good hammer-on:
1: Keep Holding the Note
The first key is the already-ringing note must continue to ring up until the hammered note is ringing. Students often make the mistake, or have trouble coordinating their fingers, and release the ringing note before the hammered note is ringing. This mutes the string and makes the hammered note weak or inaudible. This often comes from having a hard time stretching one's fingers.
2: Strike Right Behind the Fret
The second key, as with most articulations, is pressing right behind the fret. This is the point where you'll get the clearest tone with the least buzzing. If you hammer-on between the frets, you'll get weaker, buzzier notes and, more importantly, you'll have to use more force. Aim for right behind the fret for the best sound and least amount of effort.
3: Use a Quick Attack
The third key is a quick attack. I don't mean a fast rhythm. There can be a lot of time in-between the already-ringing note and the hammer-on note. What I mean by "quick attack" is when your hammering finger does come down, it comes down quickly. Why is that so important? Well, as your finger comes down it makes contact with the ringing string before the string touches the fret. If you come down too slowly, your finger mutes the string before it makes contact with the fret. This gives you a much weaker hammer-on. The volume of the ringing string drops considerably. With a quick attack you retain more of the string's vibrating energy. You get a louder, clearer note from your hammer-on.
The Rhythmic Timing Problem
A consistent problem for students playing and practicing hammer-ons is rhythmic timing. The note you're hammering must line up rhythmically like any other. Students often play the first plucked note with the correct rhythm, but rush the hammered-on notes. Be mindful of the rhythmic timing of your hammer-ons. Play slowly and use a metronome.
Can I Hammer-On More Than One Note?
Yes. While a hammer-on of one note is the most common, it's possible to hammer-on two or even three notes in a row. Four if you start on an open string!
Hammer-On Notation and Tab
In notation and tab, a hammer-on is indicated with an arced line, called a slur, connecting the different notes. Often this arc has "H" or "HO" written above or below it.
Slurs are easy to confuse with ties. Remember, a tie is an arced line connecting the same note. A tie means you hold the note through the length of the second note--they are "tied" together. A slur happens between different notes. Having the "H" or "HO" marking above/below the slur helps a reader notice, but it isn't always there.
How to Practice Hammer-Ons
The most common hammer-ons begin with the first finger holding the starting note. The hammer-on is then with finger 2, 3, or 4. You should get comfortable with these combinations first: 1-2, 1-3, 1-4 across three frets, and 1-4 across four frets (the least common, but useful).
Next, you'll want to explore every other pair of fingers like 2-3 or 3-4. Any combination is possible. Some can be quite tricky to develop the stamina and coordination, but they are worth practicing. You can stumble upon some more unique lines the more you explore.
Finally, try some 3-note hammer-ons. They aren't extremely common, but might happen in basslines with notes like b7-7-Root or a bluesy 4-b5-5 walk up.
You'll find some basic exercises and some hammer-on basslines to practice on the exercise page for this lesson.
Hammer-On Example Songs
Hammer-ons aren't unique to one style. They happen in basslines and riffs quite often. Many rock and funk songs use them to great effect.
Be sure to check out my suggestions for songs that are great hammer-on practice.