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The Effects of Rosin and Bow Tightness on Sound Production

The Effects of Rosin and Bow Tightness on Sound Production

Everytime you take your instrument out of the case, one of the first things you do is tighten the bow. It is something that many musicians do automatically, and often with little thought. Such a simple activity, yet it is one that plays a major effect on how the sound is made. Even just one turn in either direction greatly alters how the hair grips the string, which controls tone quality and projection. You may be wondering, ‘just how much should I be tightening my bow?’ To that, I must say that there is no fixed answer.

How Does the Bow Screw Function?

Before we can get into how bow tightness controls the sound of an instrument, you must first understand how the screw mechanism inside a bow works. The screw on the bow is capable of coming completely out of the bow, if loosened all the way. When the bow screw comes completely out, the frog, attached to the hair, can come off the base of the bow. This occurs when you turn the screw all the way to the left. When you turn the screw to the right, the screw pushes on a mechanism inside the frog. The pressure of this pushes the frog backwards, effectively tightening the bow.

How Rosin Controls Sound

Bows are strung with horsehair, and a popular myth about this horsehair is that it is covered in small hooks, which attach onto the string and that is what creates the sound. This is simply not true. The hair of the bow is quite smooth, and without rosin, the bow will not pull much sound at all out of the instrument. 

Rosin is a product made of resin, a substance like tree sap. Resin is extracted from trees, quite oftenly, pine and conifer trees. Tapping, the process of extracting resin from trees, involves making a hole, or some type of gouge, into a tree. After this occurs, the tree produces the sticky substance, resin, to provide protection for the tree’ wound. The excess resin is gathered, heated up, and can be combined with other materials, such as beeswax, in order to change the color of the rosin and the sound that it produces. 

When you apply rosin to the bow, you are adding a powdery, sticky substance to the smooth horse hair. The rosin creates friction, and allows the hair to grip to the string. When you pull the bow across the string, the bow is continuously gripping and releasing the string. This ‘grip and release’ process makes the string of the instrument move back and forth, creating the sound. When there is less rosin on the bow, less dramatic ‘grip and release’ action will occur. This results in less sound being produced. When more rosin is on the bow, greater ‘grip and release’ processes take place, and equates to a louder sound.

It is a logical conclusion that adding more and more rosin is better and better. More rosin, more friction, more sound. But too much rosin can have an adverse effect on your sound, due to too much friction. A player's tone may become scratchy and it will become difficult to adjust the tone quality.

Significance of Bow Tightness

Many are told when they begin their studies, to tighten their bow until they could fit a pencil in between the stick and the hair. But is this the best way to measure tightness? Some believe that bow tightness should be dictated by what is being played.

When the bow is looser, the stick has greater mobility. This allows for a greater action and more “spring” in the bow. Perfect for fast, sprightly passages, and when you want great nuance and variation in a short amount of time.

Having the bow be on the tighter end causes less mobility in the stick and greater tension on the hair. However, this tension added to the hair can be greatly advantageous, depending on what you want to accomplish. When the bow hair is more taught, more friction is created between the bow hair and the string, resulting in the possibility to pull more sound out of the instrument. This being said, making your bow subtly tighter will result in an increase of possible volume. 

Regardless of how much rosin you apply or the level of tightness of your bow, it is important to practice instrument care in order to maintain and protect your instrument. Remember to wipe your strings and the body of your instrument of any rosin when you are finished playing, to protect the wood. Also, remember to loosen your bow, to prevent it from being warped.

Article written by Erica Garcia

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