The tremolo is an interesting technique. In itself, it holds little value. After all, there is only a handful of pieces which incorporate the tremolo technique. In some circles, it is viewed with some disdain, seen mainly as a gimmicky device overused by certain players to play to the crowd (I plead guilty to this too, which I blame on youthful indiscretion). However, the importance of mastering the technique goes far beyond just the ability to amaze and astound friends and family.

It is the ultimate diagnostic tool, absolutely honest in its assessment of a player's technique. One of the hallmarks of a good technique is control over tone, the ability to produce tones that are completely even. On the guitar, most arpeggio passages are performed on three or four different strings, which can easily mask any unevenness of touch. It is only by playing the tremolo, which is essentially an arpeggio on a single string that a player can truly assess his or her own finger control. After the tremolo has been mastered, the player can then transfer the same touch to arpeggios and gain the same evenness there too.

It is not difficult to define what makes a good tremolo; there are only two criteria:

1. Evenness of tone.
2. Evenness of rhythm.

In other words, to produce a good tremolo, all the notes have to be perfectly matched and separated equally in time.

Yet what is it about the tremolo which makes it so elusive to students?

I've been grappling with this problem for the past fifteen years of teaching. And have come to this conclusion: the mastery of the tremolo technique is dependent on three factors:

1. A clean and defined attack in the tone.
2. Balance in the three fingers.
3. Good interaction between the thumb and fingers.

1. The role of the attack
In my article on scale playing, I spent some time explaining why I feel a clean attack is crucial to fast playing. Essentially it boils down to the fact that at fast tempos, all we hear are the attacks of the notes. If the attacks are undefined and weak, the notes will in turn be undefined and weak.

The term "attack" does not necessarily imply power and loudness. A tone can be soft and yet still have a clearly defined attack. It is important to make this distinction as the word "attack" can easily be misinterpreted to mean "loud." I cannot overemphasize how important it is to play light at all stages. All notes should be light and gentle. Strength and power will come when the technique has been mastered.

2. Balance in the fingers.
There are obviously different ways to achieve this. In most schools of playing, it is generally understood that the fingers of the right hand are the main activators of a stroke. However, I have found that a touch originating from the hand is much more efficient. It transfers all the action to one central source rather than have it distributed between the four fingers of the right hand.

Here is an easy way to understand this touch:

Place the "i" finger on the third string. With a very gentle motion, pull it very slightly as if to pluck it but do not let go. This pull is minimal. In fact, it should be barely perceptible to the eye. Feel the slight pressure exerted on the finger. Now let go. The string should snap free. Next try it with the "m" finger on the second string, then the "a" finger on the third string.

As you play each note, feel the weight in the hand behind each note. To best execute the stroke, the right hand position may have to be adjusted. Try pulling it back until you feel comfortable with it.

3. Thumb and finger interaction.
There is a tendency in most students to overemphasize their thumb strokes to the detriment of their finger strokes. The musical result of this is an overly loud accompaniment and a weak melodic line. To rectify this, the following exercise should be practiced.

First, place all three fingers, a-m-i on the first string. This will feel a little strange but not to worry. Next, exert the same pulling pressure on the string by pulling it very slightly. Do not let go. Now, while still holding the fingers against the first string, play the thumb on the lower bass strings, perhaps from 6th to 4th and back again.

Exercise 1

This is not so much an exercise as a way to get used to playing in two contrary directions simultaneously which is what we have to do in a tremolo. It gets us to emphasize the finger strokes and helps us to lighten our thumb strokes. This will create the correct balance between the melody, usually played by the fingers, and the accompaniment, usually played by the thumb.

The steps to achieving a good tremolo
There are several steps to practicing the technique.

Step one
In step one, the student has to develop speed in the fingers. The minimum is a quarter note to 126. Anything below that would be too slow and would not be perceived of as a tremolo. In fact, a slower tempo will make a smooth tremolo harder to achieve. The tremolo is one instance where slow practicing is not recommended. You can't learn to run by walking. True it is, you'll have to walk before you can run, but here the assumption is that the student has already learnt how to walk and is now trying to run.

In this first phase, the student will practice p-a-m-i on the 1st string. The main focus here is speed. Do not worry about any finger unevenness. The objective is to develop speed by focusing on the sympathetic motion in all the fingers.

Exercise 2

Here is an exercise for students who find it hard to play fast a-m-i strokes:

Place all three fingers on the first string. Move them together to pluck the first string. This will feel strange initially. Now release the fingers sequentially a-m-i. In other words, move the fingers as one entity but let the fingers release the string sequentially, like a reverse rolled chord (a-m-i) but on one string.

Finally add the thumb to the pattern, p-a-m-i. This will produce a fast p and a-m-i alternation but it will be very uneven. Do not worry about this unevenness. We will clean it up in the next step.

Step two
In step 2 we move to a seemingly contradictory exercise. Now that the fingers have been taught to move in one sympathetic motion, we need to separate them so that they move individually too. Each note, no matter how fast needs to be played individually.

I came up with this exercise years ago. It is rather unorthodox so brace yourself: (The faint-of-heart can skip the next two paragraphs.)

The best way to get the fingers to move individually is to bounce the right hand with each finger stroke. This is only a temporary measure so don't panic. The bouncing motion will drastically reduce the speed of the tremolo, but that's to be expected. I recommend playing this way for at least a month. It's a slow process but be patient.

The hand bouncing exercise helps develop an upward movement in the fingers, which is critical to getting finger independence.

Step three
Here is the usual regimen of exercises I give to my students. Make sure each one is thoroughly mastered before moving on to the next.

Exercise 3 

Practice a-m-i in little speed bursts.

Next, incorporate the thumb into the pattern. This exercise is for developing a smooth finger to thumb transition.

Exercise 4

Now we have to practice thumb to finger transitions.

Exercise 5

Combine exercises 1 and 2.

Exercise 6

Next, join two p-a-m-i patterns into a longer p-a-m-i-p-a-m-i pattern.

Exercise 7 

Finally a full bar of tremolo.

Exercise 8 

Here's an exercise, which I used to practice for hours at a time. Play it chromatically up to the twelfth fret and back down again. Use it as a warm up exercise too.

Exercise 9 

Additional hints
Practice your new technique on easy pieces. I recommend trying it out on Romance first. Here's a simple adaptation of the first part of Romance in tremolo.

Practice with muted strings. Put a piece of cloth underneath the strings by the soundhole. The muted strings will make it easier to spot any rhythmic inaccuracy.

Practice above the twelfth fret. The higher tension in the strings makes it easier to produce an even sound too.

Practice in longer sessions at a time. I used to play at least four hours at a time. But be sure you have a relaxed and efficient playing position before you attempt to do that. Most technical breakthroughs happen only after three hours of continuous playing. I know this may be controversial but I firmly believe it doesn't hurt to distract yourself while practicing mundane technical exercises. On the contrary, it may even help by not thinking about all the intricacies of what you are doing. The best kind of technique is one that works in the background.