How Does the Violin Work?

When I was young, I thought of the violin as a sort of magical box of mystery. To be honest, I still do just a bit. But as they say, magic is just science that we don’t yet understand. The purpose of this post is to kill a little of the magic by helping you understand how the violin works. Because nothing would bring me greater joy than helping you see the world in a less magical way.

THE RESONANCE OF THE VIOLIN: HOW VIBRATION TRAVELS

The body of the violin is a big empty box. Its purpose is to amplify the sound of the vibrating string. Have you ever had the experience of singing in the shower? Of course you have! The shower makes your voice sound more resonant. When you sing outside, you don’t get quite the same effect. The inside of the violin is like a tiny room in which the voice of the violin resonates really well.

The body of the violin isn’t just an echoing chamber, though. The wood itself gets involved in creating the sound. Touch the back of the violin and pluck an open string. You can feel the wood vibrate.

How does that happen? Well, when the string vibrates, it swings around in a circle like a jump rope. At one end of the string the bridge picks up these vibrations and transmits them to the top of the violin. In the belly of the violin there’s a wooden stick called the sound post. This stick transmits the vibrations between the top and the back of the violin. Now the whole body of the instrument is vibrating along with the string. The sound escapes the tiny room by getting out through the f-holes. This is why the sound is louder in front of the violin than it is behind it.

As an aside, you can hear the wood sing if you strike a tuning fork and touch it (gently!) to the violin. And the same goes for touching the tuning fork to a table, a chair, or even the top of your head. SCIENCE!

HOW THE STRING VIBRATES UNDER THE BOW

The bow works by friction. You draw the bow hair over the string, and that sets the string in motion. But if you’ve ever gotten a bow without any rosin on it, you’ll know that the hair isn’t naturally very grippy. If you draw an unrosined bow over the string, the hair glides over the surface without creating a sound. We need a way to make the hair grippy. So we coat it with rosin, which is made from tree sap. Now when we draw the hair over the string, the hair pulls the string with it.

Imagine how this works in slow motion. The violinist starts to play a down bow. The bow hair touches the string and starts to move to the right. The rosin in the hair grips the string and pulls it along. At some point, the string can’t travel any farther due to the tension pulling it back. So the string snaps back toward its original position. Since it’s traveling underneath the hair, it travels clockwise in a circular motion. (On an up bow, this would be counter-clockwise.) It surpasses its original position, swinging up into the bow hair slightly to the left of center. Here the rosin in the bow hair helps it grip the string once more and starts the cycle over again. Catch-Pull-Release-Catch-Pull-Release. All this happens many many times within a single bow stroke.

AMPLITUDE AND FREQUENCY

The string has only two variables to it:

1. How many times it swings in a circle per second (frequency), and
2. How wide of a circle it goes in (amplitude).

The frequency gives us our pitch. An open A string swings around 440 times per second. This is why it’s called an A440. If you tune the string down, then you’ve decreased the tension on the string. Now it swings around less frequently, maybe only going around 430 times per second. The higher the pitch frequency, the higher the pitch.

The other variable is the amplitude. The wider the string swings around, the more energy gets transmitted into the bridge. This then gets transmitted to the entire instrument, and the whole thing vibrates more. Congratulations, you’ve gotten louder!

The amplitude is our volume. The important point is that you can see it, even if you were deaf. The string vibrates its widest at the middle, halfway between the bridge and the nut. Here you can see the change in width as you play louder and softer.

EXPERIMENT: WATCHING YOUR SOUND

Keep your eye on the string as you go through this experiment. Play an open string. Start softly, and then get louder. Now get soft again. Notice how the blur of the string goes from narrow to wide and back again. Now try something different. Play an open string. As you’re playing, draw the bow closer and closer to the bridge until the sound breaks. Watch the string sputter along with the sound.

THE MAIN TAKEAWAYS

• The violin works by transmitting the vibration of the string to the body of the violin, where it’s amplified and projected out of the f-holes.
• You can see your sound by watching the string.
• If you want a good sound, pay attention to what’s going on with the string. We want it to vibrate freely.
• The string swings clockwise on a down bow; counter-clockwise on an up bow.

CONCLUSION

All this knowledge is the groundwork for how to produce a solid tone on the violin. Without it, the violin remains a mystery box that works through magic. Later we’ll get more into the practical aspects of what we can do with the bow to improve our tone quality. But for now, go forth and practice!