How the Oboe Works :: Expository Process Essays

How the Oboe Works      Ã‚  Ã‚   The oboe belongs to the group of instruments called the woodwinds.   However, it can be further classifies as all instruments can.   Instruments can be further classified by what vibrates to produce a sound.   In the case of the oboe it is air that vibrates and so it is classified as an aero phone, or enclosed or free masses of air.      Ã‚  Ã‚  Ã‚  Ã‚   There are three essential parts to every instrument. 1-The essential vibrating substance.   2-The connected reflector, amplifier, or resonator.   3-Other sound altering devices.   In the oboe these parts are the reed, the resonator, and the multiple keys.      Ã‚  Ã‚  Ã‚  Ã‚   The original source of air comes from the oboist blowing air into the reed.   The oboe has a double reed.   When air is blown it goes over and under the reeds and causes them to vibrate.   When both of these reeds are vibrating they pinch together rapidly.   This consequently disturbs the stream of air that is passing between the reeds.   This disturbance causes air molecules to bunch up leaving an empty space behind them.   The bunch of molecules is called a condensation, and the somewhat empty space of thinned out molecules is called a rare fraction.   The condensation and rare fraction of the air molecules are characteristics of a longitudinal or sound wave.   This process happens very rapidly, and is obviously followed briefly by the next puff of air, making the wave continuous.      Ã‚  Ã‚  Ã‚  Ã‚   This wave passes through the resonator.   The resonator is an object that has a specific period of vibration.   The air passes through the resonator.   This creates a specifically ordered vibration, and a constant frequency.   That is why resonators are often used in instruments to reinforce the sound of a pitch.        Ã‚  Ã‚  Ã‚  Ã‚   This specifically vibrating air enters the length of the oboe.   The bore is the interior diameter of the oboe.   It has a conical shape in the case of the oboe.   The diameter at the top of the bore is smaller than the diameter at the bottom of the bore.   As well as being conical the bore is also very narrow in the oboe.   Therefore, when the air is in the bore it is at a higher pressure at the top than at the bottom, because the air passes from a smaller opening to a larger opening.