Tuesday, March 23, 2010

String Tension Terminology

Players, violin makers, and scientists all use the same term tension to describe slightly different things. This can sometimes lead to confusion.

When scientists and engineers discuss tension, they mean the pulling force exerted along the length of a string. This is what we specify in our catalog and website. This force is determined by the amount of mass (material) on the string, the tuning (frequency at which the string vibrates) and the vibrating length of the string. For standard instruments and tunings, the string vibrating length and tuning are fixed. So the only variable that the string designer can change to affect the tension is the amount of material on the string. The more mass, the higher the tension.

When instrument makers discuss tension, they usually mean the force exerted by the strings on the top of the instrument. This force is determined by string tension as well as the geometry of the bridge and the instrument. For example, the flatter the string angle over the bridge, the less static vertical force the strings exerts on the top of the instrument. Most makers believe this force can significantly alter the sound and playing characteristics of the instrument. I’ll discuss this topic in a future post.

When players discuss string tension, they mean the subject feeling of the string from both their left fingering and right bowing hands. While this subjective feeling of tension is largely determined by the string tension, it is also affected by other factors including string response, string sound, core elasticity, the diameter of the string, etc.

Another confusing term is string gauge. Gauge refers to the diameter of the string, not the tension. In the gauge system most commonly used for gut strings, the diameter in millimeters is equal to the gauge times 0.05. For example, a 14 gauge string is equal to 0.70mm, or 0.0276" in diameter. For guitar strings, the gauge most often refers to the diameter in inches or thousands of an inch. So a 36 or .036 gauge string is 0.036" in diameter.

For an unwound string (or simple guitar strings with one type of winding), larger diameters lead to more mass and therefore higher tension. However, modern bowed strings are wound with multiple windings of different materials with different densities . Therefore, a larger diameter string may not be heavier tension. That is why bowed string manufacturers specify the tension rather than the diameter or gauge.

Friday, March 5, 2010

String Tension

One question I am often asked is about string tension. What is it? Why is it important? Why do string manufacturers offer strings in different tension grades, such as light medium and heavy?

The string playing tension is the force along the length of the string and is determined by the amount of mass (material) wound on the string. It is also determined by the string length and vibration frequency, but these are typically fixed for standard instruments and tunings.

String tension affects the response and playability of the string, as well as the sound. Higher tension strings will sound louder and can be played louder, but they are less responsive. They are more difficult to control, especially when played softly because they have more mass. While lower tension strings cannot play as loud as higher tension strings, they often have a larger tonal palette than higher tension strings.

Contrary to popular belief, higher tension strings are not necessarily brighter sounding. The opposite is often true. Since higher tension strings are inherently louder, players often bow further away from the bridge and use less bow pressure, which produces a less bright sound.

We offer most strings in light, medium and heavy tension grades. Other manufacturers may use terms such as soft and strong, or dolce and forte, or weich and stark. The medium tension is what works best for most players and instruments. However, your particular instrument and playing style may work better with light or heavy. In addition, your instrument may work best with a mixed set of different tensions. Don't be afraid to experiment!

There are no standards for tension, so one brand's "medium" tension can be different than another brand's medium. All of our string tension specifications are listed on our website: www.daddariobowed.com.

I will discuss some additional issues and myths about string tension in a future blog.