October 1999: On Muffling: Unit 1: The Nature Of Vibration

An "Ask Stephanie" reader requested that I discuss damping, also known as muffling. So the next 3 units will be devoted to that subject. -Stephanie

Damping or muffling are terms that describe ways in which we stop the vibration of strings after they have been plucked. Before we can discuss styles and requirements of muffling, we must understand the nature of vibration.

If you pluck a long, moderately thick string and observe its movement you will see that the center of the string appears to expand outward and subsequently contracts into itself. These movements alternate as the string sounds but the degree of expansion gradually decreases as the vibration subsides. Were you to pluck a thinner, shorter string, the same movements would occur but the degree of expansion would be much narrower and your eye would be hard pressed to perceive anything more than a general vibration.

If you attempt to play a neighboring string and inadvertently touch the vibrating string , you will get a "buzz". Since the degree of expansion is greater on a larger string, it is harder to avoid touching them than it is on a smaller string. All these factors necessitate various forms of muffling.

Although it is difficult to perceive visually, strings not only vibrate as a whole, but also in parts. The secondary vibrations produce what is commonly referred to as "overtones", "partials" or, "upper harmonics". . When a string is plucked, other strings are also set into motion in what is called "sympathetic vibration". The sympathetic notes usually correspond to the overtones of the primary vibrating string. If you play a string and subsequently, muffle it with a flat hand, you will often find that you have not silenced your harp. The sympathetic notes are still sounding albeit softly. All these factors contribute to resonance and quality of the instrument.

Go experiment and see what you can discover about vibration.

See you next month.

Stephanie

Would you like to ask Stephanie a question? Look for the "Ask Stephanie" link below...

Site designed by Duncan Watt for Kanuba. E-mail to: kanuba@comcast.net