The task of a speaker is not an easy one. Speakers have to convert an electronic signal coming from an amplifier, into an audible sound. The history of speakers goes back to the 19th century where they were used in the first telephone systems. With the invention of the vacuum tube in 1912, speakers became useful for the general public. Nowadays, the most commonly used type of speaker is the dynamic speaker which works by means of an electromagnetic voice coil. If this coil is fed with an audio signal it is forced to move back and forth, which causes a diaphragm - attached to the coil - to create sound waves. There are, however, several other technologies that can be used to create an audible sound, such as an electrostatic speaker. Because sound waves coming from the front and back of the speaker would interfere, most speakers are housed in an enclosure. To be clear, a loudspeaker contains one or more speakers, often referred to as drivers or transducers. Several drivers are generally used to reproduce different frequency ranges for maximum accuracy.
Leading speaker manufacturers spend a lot of time in the design of the speaker enclosure. The sound and accuracy of a loudspeaker is largely determined by the material and shape of the cabinet. Therefore, the appearance of a loudspeaker is also an important factor. As you can see, great effort is needed to get an optimum loudspeaker both in terms of design and sound quality. Very often, speaker designers and engineers have to make compromises, but there are some great looking and stunning-sounding speakers! When buying a speaker you should always listen to the speaker in a dedicated testing room, or even at your own place, with music you know and love.