Vibrato as an ornamentation
Vibrato is an ornamental technique. We add extra effect on a note by bending pitches quickly. By doing so, we are adding something special to the note.
You probably have ornaments in your place, whether they be a vase, paintings, or a mirror. And you probably thought about where you would place those. Ornaments embellish a subject, and we need to carefully place the ornament so the appropriate part of the subject is embellished. The same thing can be said when you embellish a note with ornamentations.
When we play, we have to decide which note to embellish with a vibrato. Then, we need to think about what types of vibrato to use, such as fast, slow, wide, and narrow. Also, we need to think about whether the types of vibrato would change within the note. In other words, we need to think about whether the note gets a steady vibrato throughout, more in the beginning, starts in the middle to get a swelling effect, starts fast and slows down to the end of the note, and so on. All of these things will alter the way the note is embellished.
When to start vibrating on a note
When you vibrate a note, you should choose when to start vibrating in accordance with the musical phrase. You can change the outcome of a phrase dramatically depending on when you start vibrating each note. I will simplify it and explain with these drawings.
First, we'll pretend that this line is a note.
Next, let's add a steady vibrato on top of it. The note is ornamented throughout.
What happens if we add a vibrato that starts in the middle of a note? We end up ornamenting from the middle of the note.
It would look like this if we vibrato more in the middle of a note. The note will swell in the middle.
The problem with vibrating more in the middle of a note
As I mentioned before, vibrato embellish and emphasizes the note. It is a beautiful device to use, but we will end up with an inadvertent result if we are not careful as to how to use it.
In this article, I am specifically referring to a vibrato that is not steady, or starts in the middle of a note. Let's say we are playing a dotted half note in an Allegro piece. By default, do you start vibrating from the beginning of the note, or do you start from the middle of the note? Do you keep the vibrato steady, or do you vibrate more as you play the note?
The most desirable thing to do by default is that we should vibrate from the beginning of the note, and be able to keep the vibrato steady throughout the note. We should vibrate more in the middle of the note, only when that is the part of the note you want to emphasize. Otherwise we will end up emphasizing the wrong part of the note whether we like it or not.
Look at the example below. Sing it in your head vibrating more in the middle of each note. Do you see (hear) that the line of a phrase gets chopped up whenever you change the speed and/or the width of vibrato?
After you sang it like that, this time sing it with a steady and continuous vibrato, which changes the speed and/or width only with the crescendo and diminuendo written in music. Now the music gains a beautiful long phrase.
Let's look at another example. This is the 1st theme of the 1st movement from the "Dissonance" Quartet.
The first 2 measures form a phrase, and the next 2 measures form another. The top of the phrases are the downbeat of measure 2 and 4. What if you allow those half notes to swell in the middle? You end up exphasizing the 2nd beat instead of the downbeat, which does not line up with the shape of the phrase.
When we are in a habit of vibrating more in the middle of a note, what happens as a result is a wah-wah effect, or some people call it a "sea sickness" effect. It is not a musical effect we should go after, unless the music specifically calls for it.
Examples of exceptions
Here are some examples of when you could start or increase the vibrato in the middle of a note.
In both Schubert and Bruch's examples above, the long first note could start with little or no vibrato, and add more to let the note grow as you play. It's an subjective and artistic approach that you could take.
Next examples are from Brahms.
Brahms often indicates the "hairpins" in his music as you see above. In instances like these, vibrating more in the middle of the note becomes appropriate.
Be aware of how you are vibrating
Now that we understand how a vibrato can affect musical phrasings, we need to be aware of how we are vibrating. Are we starting a vibrato from the beginning of the note? Are we keeping the vibrato steady? However we want to vibrate we have to make sure that what we have in mind is what we are actually doing.
Some students always start vibrating in the middle of a note because they want to make sure that the note is in tune before they can vibrate on it. This is both good and bad. It is good because they focus on playing in tune, and not using vibrato to hide bad intonation. However, it is bad because they get into a habit of the wah-wah effect.
If this is the case for you, I would suggest you practice with no vibrato at first until you feel confident about the intonation. Make sure that your fingers don't start vibrating on their own. Then, play under tempo, purposefully starting the vibrato from the beginning of the notes until you feel comfortable vibrating in that manner. You can then practice with faster tempi.
When we pay close attention to our vibrato, we may find that it is not as precise as we thought we were doing. One of the ways to find out how we are actually vibrating is to record ourselves play. It is important to study your own recordings carefully, and make sure your performance is coming out the way you intended. If not, figure out what the problem is, so you can come up with a solution.
Being able to vibrate from the very beginning of a note is an essential technique for a violinist if one desires to make a smooth musical phrase. It is worth spending time and effort.