These two things refer to techniques employed by the left hand to sound notes without the direct aid of the right hand. A 'hammer on' is when a note is sounded, and while it is still ringing, a left hand finger is used to quickly press down a fret that is on the same string, and close to the original fret. This will result in the sounding of the second note, even though the right hand did nothing but sound the first note. The vibrations that occurred from the sounding of the first note will be carried on to sound the second note. Here's an example. We can place our index finger on the 3rd string, 5th fret, and sound that note. While the note is still sounding, and without moving our index finger, we can use our ring finger to come firmly and directly down on the 7th fret of the 3rd string. This note will then sound, probably not as loud as the first note, but it will still sound. This is a hammer on.
A 'pull off' is basically the same thing, but backwards. We can use a finger to fret a note, and then sound that note. While the note is still sounding, a finger can be placed directly behind the first finger, and then the first finger can be 'pulled off'. In doing this, it is in effect the same as plucking the string with a finger, it creates vibrations. And now the note that is being fretted directly behind the first finger will be sounded. For example, we could place our index finger on the 5th fret, 3rd string AND place our ring finger on the 7th fret, 3rd string. We can play the note on the 7th fret, and then 'pull' that finger off the string, which at the same time, will sound the note on the 5th fret. This is a pull off.
The main difference between hammer ons and pull offs is that pull offs generate vibrations, while hammer ons generally don't. In other words, in performing a pull off, it would be possible to make the second note louder than the first. In a hammer on, we wouldn't be able to do this, because the sound will have died away slightly when we hammer on. Hammer ons and pull offs have a number of uses. They can be used to make a passage sound smoother. Sometimes we don't want to pick every note, because the pick gives a different tone than hammer on or a pull off will.
They can be used to make a passage easier to play. This is true for two reasons. The first is that we can usually do a hammer on or a pull off faster than we can pick two notes in succession. The second reason is that while we are hammering on or pulling off, with two or our left hand fingers, we can use our other two left hand fingers and our pick to do something else at the same time.
They can be used to perform 'trills'. A trill is the rapid succession of two notes. For example, if we placed our index finger on the 12 fret, 3rd string, and then sounded it, we'd get only one sound. But if we continuously hammered on to the 13 fret using our middle finger, and then immediately pulled off back to the 12 fret, we will get a continuous stream of notes, without even using the pick except for the first note. It is because pull offs generate vibrations that we are able to do this. Trills are a good way of ornamenting notes.
Like we said, we can perform trills. If we can perform trills with two notes, why can't we use hammer ons and pull offs between more than two notes? We can. With a lot of practice, we can learn to use hammer ons and pull offs with speed and accuracy, and with this skill, you can learn to play very fast. It's easier to hammer on and pull off to a note than it is to pick every note just as fast. We'll look at some of these uses of hammer ons and pull offs in further lessons. Things to remember from this lesson:
1. Hammer ons and pull offs are a means of using the left hand to sound notes with out using the right hand to sound them.
2. A pull off can generate vibrations(sound), but a hammer on will only carry on the left over vibrations from a previous note.
3. Uses of hammer ons and pull offs include smoother passages, easier passages and trills. Also, with a lot of experience using hammer ons and pull offs, one can use them to play very fast.