Loudspeaker Facts for Kids

A small speaker often found in radios.

A large speaker.

A loudspeaker, or just a speaker, is a device that makes sound. You can find speakers in many places, like radios, television sets, and musical instrument amplifiers. Speakers change electrical signals into sounds that we can hear.

How Speakers Make Sound
Different Kinds of Speakers
The History of Speakers
Images for kids
See also

How Speakers Make Sound

Speakers use both electricity and movement to create sound. First, an electrical signal comes from a radio, TV, or music player. This signal needs to be connected to an electronic amplifier to make it strong enough.

Most speakers have a few main parts:

A stiff paper cone
A coil of thin copper wire
A round magnet

These parts are often placed inside a wooden box. When the electrical signal goes through the copper wire coil, it creates a magnetic field. This field interacts with the main magnet. This causes the coil to move back and forth very quickly.

As the coil moves, it makes the paper cone vibrate. These vibrations push and pull the air around the cone, creating sound waves. These sound waves travel to our ears, and we hear the sound! Some speakers also have a special part called an audio crossover. This helps direct different sound frequencies to the right parts of the speaker.

Different Kinds of Speakers

Speakers come in different types, each designed for specific sounds.

Speakers for Low Sounds

Some speakers are made for deep, low-pitched sounds. These are called woofer loudspeakers or subwoofer loudspeakers. They are usually larger to move more air and create those deep bass notes.

Speakers for High Sounds

Other speakers are called tweeters. These are designed to make high-pitched sounds. Think of the sound of a whistle or a bird singing. Tweeters are often smaller.

Speakers for Instruments

Loudspeakers used for electric musical instruments are usually much stronger. They are also heavier than speakers for radios or TVs. Their main job is to turn the electrical signals from an instrument into loud, clear music.

The History of Speakers

The first speaker that could make sound was invented in 1876. Alexander Graham Bell created it. He needed a way to make sounds louder for his telephone invention.

Later, in 1878, a German inventor named Werner von Siemens made an even better speaker. His design was an improved type of electrodynamic loudspeaker. However, it still needed a separate amplifier to make the sound truly loud.

Images for kids

A home speaker system with three types of drivers:
1. Mid-range driver
2. Tweeter
3. Woofers
. The hole below the lowest woofer is for a bass reflex system.
Kellogg and Rice in 1925 with an early moving-coil cone loudspeaker.
A cutaway view of a speaker for bass sounds.
1. Magnet
2. Voicecoil
3. Suspension
4. Diaphragm
A cutaway view of a speaker for mid-range sounds.
1. Magnet
2. Cooler (sometimes present)
3. Voicecoil
4. Suspension
5. Diaphragm
A cutaway view of a tweeter speaker, which makes high-pitched sounds.
1. Magnet
2. Voicecoil
3. Diaphragm
4. Suspension
A four-way, high-quality speaker system. Each of the four parts makes a different sound range.
An exploded view showing the parts of a dome tweeter.
The electronic symbol for a speaker.
An unusual three-way speaker system.
A three-way speaker that uses horns for each of its three parts.
Two-way binding posts on a speaker, connected using banana plugs.
A speaker with two pairs of binding posts, ready for bi-wiring.
An HP Roar Wireless Speaker.
A label showing the specifications of a loudspeaker.
Diagrams showing how sound spreads from a public address speaker at different frequencies.
A moving iron speaker from 1929.
A piezoelectric buzzer.
A magnetostatic loudspeaker.
A diagram showing how an electrostatic speaker is built and connected.
In Heil's air motion transducer, the membrane moves in a magnetic field, pushing air in and out.
A plasma speaker.