Speakers
Everyone in our modern world has used speakers at one time or another for one purpose or another. Speakers can be found in every electronic device we use today, including computers, iPods, cell phones, hearing aids, and more. But how do they work? Could we listen to our favorite music without speakers? And how have they changed over the years? Whether you're looking to purchase a new audio system, build on your existing system, or you're just plain curious, here's some basic information on the history of speakers and how they work.
In the simplest terms, speakers create sound. That's really all they do. To understand how a speaker works, it is necessary to first talk about what sound is and how it is produced. Sound is the energy created by the variation in air pressure that is caused when objects move or vibrate. The ear is the receiver of sounds. Inside the ear is the tympanic membrane, or more commonly, the eardrum. The eardrum is a thin membrane that is shaped like a cone whose function is to transmit sound. When the eardrum vibrates, the brain interprets those vibrations as sound or sound waves. The most common manner of vibrating the eardrum is with rapid changes in air pressure. When an object vibrates in air, liquids, or solids, energy is transmitted to air particles around that object. Think of a ripple or wave produced in water. The length of a single wave is described as 'frequency.' When an object vibrates, the frequency is affected by the speed of that movement or vibration. Slower vibrations produce lower-frequency sounds, whereas faster vibrations produce higher-frequency sounds. When the waves reach the ear, the eardrum vibrates back and forth, and the brain interprets that movement or vibration as sound.
Speakers, of course, come in all sizes from the tiny one that fit inside an ear, to the mammoth-sized speakers you see at a rock concert. Regardless of their size, however, all speakers work the same ... pretty much like ears do. The basic parts of a speaker, also, are pretty much the same. They include magnet, speaker cone, wire coil, spider, diaphragm, and driver.
The voice coil is a coiled piece of metal that wraps around a cylinder that conducts electricity to the speaker's magnet. The diaphragm is the plastic or fabric facing outward of the speaker. The spider is a piece of material that is folded like an accordion, and it connects the voice coil and the diaphragm. The spider moves with the diaphragm and voice coil. When a signal is sent from a stereo, it is transmitted as an alternating current, which means it constantly switches back and forth between positive and negative electrical charges. In turn, when this charge hits the speaker's magnet, it polarizes it, or gives it a negative or a positive charge. Because the current strikes the magnet multiple times per second, the charge of the magnet switches back and forth very quickly. This rapid movement causes it to push the voice coil up and down in a piston-like motion. The coil then makes the diaphragm vibrate, and that in turn creates sound waves. The initial signal and the speaker drivers are what determine how rapidly the coil will move, and this controls the sound waves. Drivers come in three sizes: tweeters, which are smallest in size; midrange or medium; and woofers, which are largest in size. The tweeters, because they are small, have the capability of vibrating quickly, and that rapid movement creates higher frequencies. Conversely, woofers, because of their larger mass, transmit lower frequencies.
One way volume can be controlled is with resistors. Resistors are electronic components that regulate the electric flow in a given electronic device. Aptly named, they create resistance because these devices permit the introduction of precisely controlled amounts of resistance into electrical circuits. The speaker's volume knob is a part of the electronic component known as a variable resistor. Turning down the volume in a speaker means you are really turning up the resistance in a circuit that is controlling the speaker. Conversely, turning up the resistance means the electric current that flows through it is reduced. Virtually every electronic device contains resistors.
Speakers often also include amplifiers. These amplifiers are composed of transistors made up of semiconductors, which are materials that conduct electric current. Capacitors are also an important part of the speakers in many devices because they create louder sound with greater production of bass, which amplifies the volume of speakers.
Though they might not look like much, speakers are complicated and intricate electronic components of any audio system. The electronic parts of a speaker allow for precise control of such aspects of sound as volume and bass, as well as minimization of distortions. Simply put, the quality of your speakers can make or break your listening experience.
In the simplest terms, speakers create sound. That's really all they do. To understand how a speaker works, it is necessary to first talk about what sound is and how it is produced. Sound is the energy created by the variation in air pressure that is caused when objects move or vibrate. The ear is the receiver of sounds. Inside the ear is the tympanic membrane, or more commonly, the eardrum. The eardrum is a thin membrane that is shaped like a cone whose function is to transmit sound. When the eardrum vibrates, the brain interprets those vibrations as sound or sound waves. The most common manner of vibrating the eardrum is with rapid changes in air pressure. When an object vibrates in air, liquids, or solids, energy is transmitted to air particles around that object. Think of a ripple or wave produced in water. The length of a single wave is described as 'frequency.' When an object vibrates, the frequency is affected by the speed of that movement or vibration. Slower vibrations produce lower-frequency sounds, whereas faster vibrations produce higher-frequency sounds. When the waves reach the ear, the eardrum vibrates back and forth, and the brain interprets that movement or vibration as sound.
Speakers, of course, come in all sizes from the tiny one that fit inside an ear, to the mammoth-sized speakers you see at a rock concert. Regardless of their size, however, all speakers work the same ... pretty much like ears do. The basic parts of a speaker, also, are pretty much the same. They include magnet, speaker cone, wire coil, spider, diaphragm, and driver.
The voice coil is a coiled piece of metal that wraps around a cylinder that conducts electricity to the speaker's magnet. The diaphragm is the plastic or fabric facing outward of the speaker. The spider is a piece of material that is folded like an accordion, and it connects the voice coil and the diaphragm. The spider moves with the diaphragm and voice coil. When a signal is sent from a stereo, it is transmitted as an alternating current, which means it constantly switches back and forth between positive and negative electrical charges. In turn, when this charge hits the speaker's magnet, it polarizes it, or gives it a negative or a positive charge. Because the current strikes the magnet multiple times per second, the charge of the magnet switches back and forth very quickly. This rapid movement causes it to push the voice coil up and down in a piston-like motion. The coil then makes the diaphragm vibrate, and that in turn creates sound waves. The initial signal and the speaker drivers are what determine how rapidly the coil will move, and this controls the sound waves. Drivers come in three sizes: tweeters, which are smallest in size; midrange or medium; and woofers, which are largest in size. The tweeters, because they are small, have the capability of vibrating quickly, and that rapid movement creates higher frequencies. Conversely, woofers, because of their larger mass, transmit lower frequencies.
One way volume can be controlled is with resistors. Resistors are electronic components that regulate the electric flow in a given electronic device. Aptly named, they create resistance because these devices permit the introduction of precisely controlled amounts of resistance into electrical circuits. The speaker's volume knob is a part of the electronic component known as a variable resistor. Turning down the volume in a speaker means you are really turning up the resistance in a circuit that is controlling the speaker. Conversely, turning up the resistance means the electric current that flows through it is reduced. Virtually every electronic device contains resistors.
Speakers often also include amplifiers. These amplifiers are composed of transistors made up of semiconductors, which are materials that conduct electric current. Capacitors are also an important part of the speakers in many devices because they create louder sound with greater production of bass, which amplifies the volume of speakers.
Though they might not look like much, speakers are complicated and intricate electronic components of any audio system. The electronic parts of a speaker allow for precise control of such aspects of sound as volume and bass, as well as minimization of distortions. Simply put, the quality of your speakers can make or break your listening experience.