There are so many ways to enhance tone on a violin. I don't think it's a mistake that teachers will often refer to "tone color." Much like the various colors on an artist's palette, each unique tone will create a different mood and has a different purpose within a performance. And how many ways are there to achieve these variations in tone color? Well, they aren't kidding when they say, "The sky's the limit." (My husband will often speculate, "Who ARE they, and why do they say these things?")
Of course, you can change the color of your sound with vibrato of varying amplitudes and speeds; with a fast or slow bow; with the amount of gravity (weight) or suspension you encourage in your right arm; where you decide to place the bow in relation to the bridge of the violin, or the frog of the bow, etc. It all makes a difference. Wikipedia describes the science of it this way in its article on Violin acoustics: "In bowing, the three most prominent factors under the player's immediate control are bow speed, force, and the place where the hair crosses the string (known as the 'sounding point'): a vibrating string with a shorter length causes the sounding point to be positioned closer to the bridge. The player may also vary the amount of hair in contact with the string, by tilting the bow stick more or less away from the bridge. The string twists as it is bowed, which adds a 'ripple' to the waveform: this effect is increased if the string is more massive."
But there are other more subtle factors as well, including hardware on the instrument, adherence to accepted posture guidelines, and let's face it—the pure imagination of the player! I won't even explore what goes into the makings of the violin itself in this post. In terms of hardware, I mean tuners, chin rests, or even mutes. The following paragraphs on mutes are an example of how a little piece of supplementary hardware can make a big difference. This was taken from an article I wrote for Everything Strings, a newsletter I started when I worked as a string specialist at Riverton Music in Sandy, UT.
"You may think a mute is there to make your sound softer. That is true, to a point. But often composers will call for a mute in a symphony simply for a change in tone color.
"A mute for an orchestral stringed instrument works by putting pressure on the bridge, which dampens and reduces the vibrations of sound emitting from the instrument. Little known fact: technically, anything that puts pressure on the bridge (not just a traditional mute) can have the needed effect. In a pinch, I've resorted to using a dollar bill, folded up against the bridge (woven in between the strings), or even a large paper clip on top of the bridge! That being said, I highly recommend getting an actual mute. They are inexpensive (starting at $2.50) and designed to work better than homemade adaptations. They look classier, too, and are less distracting.
"An orchestral mute is small, often round, and will typically stay on the strings behind the bridge until you are ready to put it on. You use it when you play in a symphony, chamber group, or while performing a solo, when the words con sordino (Italian for “with mute”) appear in your music. Since one of these mutes is designed to stay on the strings of the violin, even when it's not being used on the bridge, there's little chance of it getting lost, unless you purposely take it off.
"A practice mute is usually bigger, bulkier, and heavier, and stays in a compartment of your case until you're ready to use it. As you may suspect, the purpose of a practice mute is to reduce your sound as you practice. Practice mutes mute your sound A LOT. (They're great for hotel rooms, or for parents who complain about too much “noise” when you practice.) It works the same way; simply place it on top of the bridge. There are grooves cut in it to make room for the strings. Most practice mutes are made of rubber or metal. I have a metal one that is VERY effective."
Interesting stuff. But as you know, experimenting with mutes is only one aspect of getting different sounds from the violin. I mentioned posture. There have been countless times that I have encouraged a student to "bend your thumb," "curve your pinky," "relax," "keep your instrument up," "keep space between your left thumb and the fingerboard," "bend your knees," etc., and even one little tiny change such as this has truly—sometimes intensely—improved the clarity and roundness of their tone. Don't ask me how it works (whether or not I know). It's still amazing to me. This week I encouraged a viola student—yes, I do have a couple of those—to straighten her left wrist. She did so, started her passage again, and the change in her sound was both immediate and dramatic. She paused her playing, her eyes went wide, and I chuckled in delight. Her mom heard the difference, too. It was like someone had added a fifth dimension of purity and depth to her tone. Who knew that posture wasn't just about appearance?
Folks might also be surprised at how much a player's mental work can be transmitted through the music to the audience. When I play a hymn in church, I'll often think of the words while I play. It reminds me of the importance of the music's message. I will usually try to tell some sort of story with my emotions, no matter what style of piece I'm playing. It makes it more interesting for me, and the emotions I pour in are often detected by those who are paying attention, whether it's through the expressions on my face, or simply through the change in sound: in other words, the tone color.
Books have been written on tone. Teachers expound on this constantly. Maybe this post will serve as a reminder to experiment with different ways to enhance your tone.