HOW DOES THE SOUND REACH OUR EAR?
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From the previous section, you should have learnt how CD players work, now you need to find out is how the sound from the loud speaker reaches our ears. To the left is a diagram of a loud speaker which is a translation machine, meaning that it changes electrical signals into physical Vibrations that can be heard by the ear.
EACH PART OF THE LOUDSPEAKER HAS A SPECIFIC JOB...
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There are many parts of the speaker, each component plays an important role in producing sound, here are the most significant parts....
THE CONE/DIAPHRAGM - The cone is the main section of the Loudspeaker that is made to vibrate by the Driver, and connected to the Voice Coil , this can be made from either metal, paper or plastic. It is allowed to move by the suspension.
SUSPENSION - The suspension is attached to the Diaphragm, it is an edge or rim of flexible material which brings together the Diaphragm and the Driver (Basket). Its job is to pull the cone back to the center position, acting like a spring, when it moves back and forth.
SPIDER - The spider attaches the voice coil and the diaphragm, pulling the cone back to the center position, acting like a spring, when it moves back and forth.
THE CONE/DIAPHRAGM - The cone is the main section of the Loudspeaker that is made to vibrate by the Driver, and connected to the Voice Coil , this can be made from either metal, paper or plastic. It is allowed to move by the suspension.
SUSPENSION - The suspension is attached to the Diaphragm, it is an edge or rim of flexible material which brings together the Diaphragm and the Driver (Basket). Its job is to pull the cone back to the center position, acting like a spring, when it moves back and forth.
SPIDER - The spider attaches the voice coil and the diaphragm, pulling the cone back to the center position, acting like a spring, when it moves back and forth.
voice coil and magnet...
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VOICE COIL - The voice coil is what is known as a basic Electromagnet, it is piece of magnetic metal such as iron with a coil of wire which has been wrapped around the metal. When an electrical current from an Amplifier passes through this a magnetic field is created around the coil. This gives magnetic properties to the metal which it is surrounding, just like any other permanent magnet, this field has poles. However these change according to changes of direction in the flow of current. Therefore if the direction of the current reversed, the poles (south and north ends) of the voice coil would switch, this could happen more than once a second.
MAGNET - This is a permanent magnet which cooperates with the electromagnet (voice coil), they are connected by poles, for instance the negative end of the voice coil is attracted to the positive end of the permanent magnet, however the negative pole of the voice coil is repelled by the negative pole of the permanent magnet. When the flow reverses and the poles switch, the direction of which the magnets are repelling and attracting changes, quickly pushing the coil back and forth.
MAGNET - This is a permanent magnet which cooperates with the electromagnet (voice coil), they are connected by poles, for instance the negative end of the voice coil is attracted to the positive end of the permanent magnet, however the negative pole of the voice coil is repelled by the negative pole of the permanent magnet. When the flow reverses and the poles switch, the direction of which the magnets are repelling and attracting changes, quickly pushing the coil back and forth.
how does this work together?
The permanent magnet and voice coil repel and attract against each other due to changes in current direction, resulting in the coil being frequently pushed, this then pushes and pulls on the speaker cone or diaphragm which vibrates the air particles directly in front of the speaker creating sound waves.
HOW DOES THIS SOUND TRAVEL?
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Sound travels in sound waves and is a form of energy. Sound is created through vibrations in particles, these vibrations are passed to other molecules. This is why sound can't travel through a vacuum. The amount of force given off by each particle is given in decibels. Therefore the speaker would vibrate, sending vibrations along the air particles (a lot like a slinky) until it reached the ear.
sound waves -
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There are changes in sound waves which alter the note produced -
FREQUENCY - The frequency in a sound wave is the wave length, this alters pitch. The smaller the wavelength, the higher the frequency and pitch.
AMPLITUDE - The amplitude in a sound wave is the length from the middle of the wave to the top, this alters volume. The higher the amplitude the higher the Volume.
FREQUENCY - The frequency in a sound wave is the wave length, this alters pitch. The smaller the wavelength, the higher the frequency and pitch.
AMPLITUDE - The amplitude in a sound wave is the length from the middle of the wave to the top, this alters volume. The higher the amplitude the higher the Volume.