By reading the previous blog post, you now know the history of speakers, how sound is created and the parts of a speaker. We all should be comfortable with the fact that sound is travelling, mechanical wave. But now you all may start to be wondering how exactly do speakers create these waves? A speaker is a relatively simple device, and is important to understand the basics of how they work especially before incorporating them into your home theater system.
The sound that emanates from a speaker is due to the movement of a diaphragm, which compresses and expands the air around it. We know that loudspeakers translate an electrical signal into an audible sound and this happens because a speaker contains an electromagnet. The movement of the diaphragm is started by an electromagnet attached to it. An electromagnet is a magnet which is created by a current-carrying coil of wire. In addition to an electromagnet, every speaker also contains a permanent magnet. The permanent magnet creates a force on the electromagnet, causing the electromagnet and diaphragm to move.
A circular coil of wire called the voice coil is attached to a cone and sits in the gap of a circular magnet. The flexible spider keeps the voice coil centered in the gap so that it does not rub on the magnet. The surround attaches the open end of the cone to the frame of the loudspeaker. The coil in the electromagnet behaves much like a permanent magnet; it reverses the direction of the current in the coil which flips the poles of the magnet. Inside the speaker, an electromagnet is placed in front of a permanent magnet. The permanent magnet is firmly fixed into position whereas the electromagnet is not firmly fixed.
When a current passes through the wire coil, a magnetic field is created inside the coil (this is commonly called an electromagnet). This electromagnet has a north and south pole just like a permanent magnet. The electromagnet feels a force from the permanent magnet in its center. In response to this force, the electromagnet and the diaphragm move. The movement of the diaphragm causes air to be compressed. When the direction of the current is reversed, the magnetic field of the electromagnet also is reversed. This flips the direction of the force on the electromagnet and in turn, changes the direction it and the diaphragm move. This movement then allows the air near the surface of the diaphragm to expand. This process of compressing and expanding the air is how a sound wave is created in a speaker. A current through the voice coil in the magnetic field causes a force on the coil and thus the cone. The current normally oscillates in a loudspeaker. When the current is reversed, the force is downward. The cone thus oscillates, generating compressions and expansions of air which travel outward. That is sound! The loudspeaker transduces electrical energy into acoustic energy.
Speakers as we know them are constantly vibrating back and forth. This is accomplished by hooking the coil of wire to a source of alternating current. As the current changes direction, the diaphragm follows by vibrating forward and backward at the same frequency, producing a sound wave at the frequency of the alternating current.
In this blog post you have learned how speakers work. For my next blog post I will be discussing about the importance of the design of speakers and I will also be creating as well as dismantling a speaker! If you haven’t already, check out my last blog post which is below and see you next time!
The sound that emanates from a speaker is due to the movement of a diaphragm, which compresses and expands the air around it. We know that loudspeakers translate an electrical signal into an audible sound and this happens because a speaker contains an electromagnet. The movement of the diaphragm is started by an electromagnet attached to it. An electromagnet is a magnet which is created by a current-carrying coil of wire. In addition to an electromagnet, every speaker also contains a permanent magnet. The permanent magnet creates a force on the electromagnet, causing the electromagnet and diaphragm to move.
A circular coil of wire called the voice coil is attached to a cone and sits in the gap of a circular magnet. The flexible spider keeps the voice coil centered in the gap so that it does not rub on the magnet. The surround attaches the open end of the cone to the frame of the loudspeaker. The coil in the electromagnet behaves much like a permanent magnet; it reverses the direction of the current in the coil which flips the poles of the magnet. Inside the speaker, an electromagnet is placed in front of a permanent magnet. The permanent magnet is firmly fixed into position whereas the electromagnet is not firmly fixed.
When a current passes through the wire coil, a magnetic field is created inside the coil (this is commonly called an electromagnet). This electromagnet has a north and south pole just like a permanent magnet. The electromagnet feels a force from the permanent magnet in its center. In response to this force, the electromagnet and the diaphragm move. The movement of the diaphragm causes air to be compressed. When the direction of the current is reversed, the magnetic field of the electromagnet also is reversed. This flips the direction of the force on the electromagnet and in turn, changes the direction it and the diaphragm move. This movement then allows the air near the surface of the diaphragm to expand. This process of compressing and expanding the air is how a sound wave is created in a speaker. A current through the voice coil in the magnetic field causes a force on the coil and thus the cone. The current normally oscillates in a loudspeaker. When the current is reversed, the force is downward. The cone thus oscillates, generating compressions and expansions of air which travel outward. That is sound! The loudspeaker transduces electrical energy into acoustic energy.
Speakers as we know them are constantly vibrating back and forth. This is accomplished by hooking the coil of wire to a source of alternating current. As the current changes direction, the diaphragm follows by vibrating forward and backward at the same frequency, producing a sound wave at the frequency of the alternating current.
In this blog post you have learned how speakers work. For my next blog post I will be discussing about the importance of the design of speakers and I will also be creating as well as dismantling a speaker! If you haven’t already, check out my last blog post which is below and see you next time!