STRINGED+INSTRUMENTS+-+DENIS

Musical instruments are set to vibrate at their natural frequency, the frequency at which they will vibrate naturally, when an object somehow disturbs the object. e.g. when a person plucks a guitar string.

When a guitar string is plucked, the vibrating string causes the air particles within the sound box to vibrate at the same natural frequency of the string. Furthermore, the string is capable of forcing the other strings vibrating at their fundamental frequency, which is the lowest possible frequency of a periodic waveform. This notion, where an object affects another in this manner, is called as Forced Vibration. For example, when an A string is plucked, it vibrates at 440 Hz. This causes the E string to vibrate at 330 Hz whilst the air particles vibrated at a similar 440 Hz. In this case, the A string is known as the driving oscillation, the oscillation that causes the rest.

The natural frequency of an object can only be changed should the physical properties of the object be changed. This is known as damping. A heavy damping causes the oscillation to slow down whilst a light damping causes the system to continue virtually unchanged. The final stage, critically damped indicates the most intense sorts - the system almost immediately returns to 0. String A can be "damped" by control the tightness or length of the string. A method to damp it further is to pluck the guitar whilst it is submerged in oil.

Guitar Resonance - youtube Guitar Resonance - sound box [|Natural Frequency]