What is Speaker and how does it work ?

Although stereo is a big improvement on mono, it's still only two-dimensional sound.

To reproduce all the different frequencies of sound in a piece of music faithfully, top quality speakers typically use different sized cones dedicated to high, medium and low frequencies.

It is possible to make loudspeakers sound three-dimensional, but you need more speakers to do it.

A microphone uses the same mechanism as a speaker in reverse to convert sound into an electrical signal. In fact, you can even use a pair of headphones as a microphone!

Quad (quadrophonic) sound is like double stereo: you have two speakers in front of you and two behind.

Loudspeakers are also known as ‘speakers’ and they convert and project sound in response to an electric signal.

Now the sound can move behind you or in front as well as from side to side. Surround sound used in movie theaters (cinemas) works in a similar way.

Loudspeakers are found in most radios, music players and TV receivers, and can be also found in many other electrical devices that produce sound.

Binaural is a way of making a sound recording seem three-dimensional with only two speakers.

In 1861, Johann Philipp Reis put a loudspeaker in his telephone, and in 1876, Alexander Graham Bell gained a patent for a loudspeaker as part of his telephone, and Ernst Siemens, a German, patented an improved loudspeaker in 1877.

Our ears are more than just holes through which sounds enter. The hills and valleys in our outer ears help us to work out where sounds are coming from and give the sounds we hear in the world their three-dimensional quality.

Loudspeakers can be either wired using audio cables, or wireless with the speaker transmitting sound via radio signals.

Normal stereo recordings don't pick up this directional information, because ordinary microphones don't have the hills and valleys that our ears have.

The position of a loudspeaker in a room, as well as the position of the person, the size of the room, and how sound absorbing the room is, all affect the sound quality coming from the speaker.

Binaural recordings are made a different way using a dummy's head with plastic ears shaped like a human's.

The most common type of speakers uses a cone that is attached to an electromagnet, which responds to an electrical signal, causing the cone to vibrate and produce sound.

Many different types of loudspeakers have been produced over the years, including horn, electrostatic, magnetostrictive, bending wave, flat panel, plasma arc and digital loudspeakers.

Two microphones are placed inside the ear holes so they pick up noises like human ears would.

Loudspeakers are usually housed in a type of box, so the sound waves at the back and the sound waves at the front don’t interfere with each other and negatively affect the sound quality.

When sound is recorded binaurally, in this way, and then played back with conventional headphones, it sounds strikingly different to stereo—and almost lifelike. A binaural recording of a jet plane taking off sounds just like it's moving through your head!

Loudspeakers often have different drivers to reproduce different frequencies of sound, and these are called ‘woofers’, ‘sub woofers’, ‘tweeters’, ‘supertweeters’ and ‘mid-range speakers’.

Loudspeaker cones or diaphragms are usually made from paper, polypropylene or aluminium, or a combination of these materials.