Blog challenge day 7: how violins work

Unless you're a random stranger who stumbled upon this blog, you probably know that I play the violin. I started playing when I was four years old and music has been a big part of my life ever since.  I've performed with a lot of groups around St. Louis and also recorded on a few albums. I used to play a lot of wedding gigs but I'm semi-retired from that now.

I can talk about music all day long and I have lots of stories to tell. Today I'm going to focus on the basic anatomy of violins and how they produce sound. I'm no expert luthier (I know a lot more about playing than making violins) and not too great at explaining scientific stuff so I'm going to keep it pretty simple. Also, I'm going to focus only on mainstream acoustic violins today, not electric or other specialty violins. Please feel free to add comments if you know a lot about making instruments!

Violins serve a practical purpose (they make music) but they are also works of art that require a lot of craftsmanship. An instrument that is well-made can last multiple centuries if it is properly cared for; many of the world's best soloists play instruments that are hundreds of years old. The Stradivarius violins you've probably heard of were made in the late 1600s-early 1700s.

First, the basics: violins are hollow on the inside. It's kind of hard to tell just by looking at them, but if you ever see one up close you can look inside those curvy cut-outs (called f-holes) on the front. The main part of a violin is called the "body." The body comprises a large top piece, called a sounding board (the main brown part you see in the picture below); ribs (curvy side parts); and a back. The back can either be a single piece of wood or two identical halves--the example above has a back that's two pieces, which you can tell from the seam running down the middle. The top/soundboard should always be a single piece of wood. 

The pieces of a violin are held together with special glue. Here's a picture of a violin body, mid-construction:

Materials: the top/soundboard of a violin is traditionally spruce. The back and ribs are typically maple. These pieces are coated with varnish during the construction process, which is what gives a violin its shine. It can also affect the color of a violin.

The skinny black part that connects the body of the violin and the scroll is called the neck. If you ever get to look at a violin up close, pick it up by grasping the neck with one hand. Try to avoid touching the body of a violin as much as possible - the oils in our skin are not good for the varnish. You might be surprised by how light a violin is once you pick it up. Even the full-size ones weigh only about two pounds.

A note on instrument etiquette: stringed instruments are very delicate and sensitive to external stimuli (temperature, moisture, pressure, etc.) Never touch someone else's violin without asking their permission first. If they give you permission to handle it, be extremely gentle. Imagine you're holding a baby bird that was just born. I usually let people touch and examine my violins if I'm there to supervise.

The underside of the neck is usually made of maple, like the back and ribs. The top side of the neck is called the fingerboard - this is the long black piece under the strings. The fingerboard is typically made of ebony because it's a very hard wood that doesn't wear out easily.

Traditional violins have four strings tuned in perfect fifths: G, D, A, E (left to right/low to high). The strings themselves are coiled around the tuning pegs--you loosen or tighten the pegs to tune a violin. Sometimes you will also see micro-tuners installed at the other end of the strings. These are used to make smaller tuning adjustments, because tuning with pegs alone can be pretty difficult (especially for small children). The first few years you play, your instrument will probably be tuned by your teacher because it takes time to develop your ear and the fine motor skills needed to maneuver the pegs. I learned how to properly tune a violin using only the pegs when I was 13.

That little piece of wood holding up the strings is called the bridge. It suspends the strings above the fingerboard so you can press down in different places to make different notes. It's very important that the bridge on a violin always stays perfectly vertical. The bridge is not glued to the body of the violin; it stays in place purely because of the tension of the strings. Take extra care to never crush the bridge or knock this part against anything. Even when a violin is properly secured in a case, it should not be stored upside down. The bridge should always be facing up or to the side, never down.

Here's a side view:

One of my favorite parts of the violin (because it has a funny name) is the little double line that runs around the edge of the frond and back pieces -- this is called purfling.

The purfling on good-quality violins is a wood inlay, though you can also find ornate violins with a mother of pearl inlay. Cheaper violins will have the purfling painted on.

Then you've got your bow:

The screw on the end turns to tighten and loosen the hair. The hair of a violin bow is another place to avoid touching because the oils in your skin are bad for it. The frog is the main part of the bow that you hold with your right hand.

Violin bows are also pretty light - less than a pound. That doesn't make them easy to maneuver. Most people I've talked to who tried to learn violin say mastering the bow is the hardest part.

Now that you know the most important parts of the violin, let's talk about sound.

Making Sound

This is where I may do a poor job of explaining the science stuff. One of the more important pieces that affects the sound you hear from a violin cannot be seen from the outside. Inside the body of the violin, there's a small vertical post connecting the front and back pieces--this is called a sound post. It serves two purposes: it provides structural support and helps transfer sound between the front and back of the violin. The sound post is usually positioned somewhere in the middle of the violin. Its precise location will affect the instrument's tone, volume, brightness, etc.--all the qualities that determine an individual instrument's unique sound. You can see the sound post near the middle in the diagram below:

You can make sound on a violin in a few different ways, but for the sake of simplicity I'm going to focus just on the primary method: using a bow.

This little animation shows a slowed down version of what happens when you drag a violin bow across the strings. The motion of the bow should be perpendicular to the strings. If your bow is crooked and not perfectly perpendicular, it won't produce as rich or clear of a sound. It takes a lot of practice to keep the bow in the right place all the time and this is something violinists have to practice throughout their lives. Here's another view of what happens when you move the bow across a string:

The hair on a violin bow is coated with rosin to give it some stickiness and produce more friction between bow and string. Wikipedia has a good concise explanation of how a violin produces sound:

The sound of a violin is the result of interactions between its many parts. Drawing a bow across the strings causes the strings to vibrate. This vibration is transmitted through the bridge and sound post to the body of the violin, which allows the sound to effectively radiate into the surrounding air. The tension and type of strings, placement and tension of the sound post, quality of the bow, and the construction of the body, all contribute to the loudness and tonal quality of the sound.

So while it looks simple to create sound on a violin, what you hear is the result of a lot of different pieces working together. The material quality and structural integrity of every piece of a violin will affect its overall sound. You can also manipulate the tonal qualities with your bowing technique--which parts of the bow you use, length of stroke, bowing speed, amount of downward pressure you apply on the frog, etc. If I listen to a recording of a violinist, I can tell what direction the bow is moving at any given moment, which part of the bow they're playing with, when they change directions, etc. Anytime you have a group of violins playing the same part (like in an orchestra), it's important they all use the same bowings to create a cohesive sound.

Some technical terms for the processes you see above, in case you're interested:

stick-slip phenomenon and static friction - these terms describe the interplay between bow and string

standing waves - the kind of sound waves violins make. The body of the instrument acts as a resonator.

I grew up with the Suzuki method and we used analogies for all these phenomena to make them easier for kids to understand. Regardless of what words you use to describe this process, I think it's pretty cool!