Speakers, as part of a speaker system, function by converting electrical signals into acoustic signals. For this reason, they are often referred to as electro-acoustic transducers. There are several types of speakers that differ from one another based on the principle by which they convert electrical energy into mechanical energy—that is, ultimately into sound. For home use, electrodynamic and electrostatic speakers are the most common choices.
Electrodynamic Speakers
This category or type includes virtually all home speaker systems found in households, whether in the living room or as an accessory to a computer, etc. These speakers operate on the principle of a voice coil in the magnetic field of a permanent magnet.
The diaphragms of the drivers in this type of speaker are primarily made of paper, Kevlar, or carbon fiber. In practice, three types of speaker drivers are distinguished. The tweeter is responsible for reproducing high frequencies and has the smallest diameter. In contrast, the midrange driver handles the reproduction of midrange frequencies, i.e., frequencies ranging from hundreds to thousands of hertz. And the woofer, or bass driver, handles the reproduction of the lowest frequencies, i.e., in the tens to hundreds of hertz.
Electrostatic Speakers
Although they are used less frequently today, they still have their fans. There are many reasons for this. This type of speaker operates on the principle of a very thin membrane with a conductive layer. It is positioned between two electrodes, which are usually made of metal. A major disadvantage of these speakers is their considerable size. However, newer models demonstrate that combining the advantages of an active electrodynamic woofer with the smaller surface area of an electrostatic driver for the midrange and treble frequencies can, in fact, yield certain benefits.
Nevertheless, one of the downsides of electrostatic speakers is undoubtedly the need for a relatively high polarization current between the electrodes. Headphones are also manufactured using electrostatic transducers.
It is worth noting that electrostatic speakers are characterized by a unique reproduction of the midrange and treble, which sounds completely different from what is typical of conventional electrodynamic speaker systems.