Speakers, loudspeakers, or speaker systems are output devices through which electrical signals come out as sound. It is in fact an electromechanical transducer, which is very much responsible for the quality of the sound that comes out. Loudspeaker is a general term. It may include a set of speakers, a single device or a set of drivers, or piezoelectric speakers. Loudspeakers are variable instruments and are available in a lot of sizes, shapes and qualities.

The accuracy of a loudspeaker is one of the primary concerns we look for before selecting one. Some of the popular type of loudspeakers and drivers include woofers, sub woofers, horn loudspeakers, piezoelectric speakers, electrostatic loudspeakers, ribbon and planner magnetic loudspeakers, bending wave loudspeakers, flat panel loudspeakers, distributed mode loudspeakers, plasma arc speakers, and digital speakers.

The performance of a loudspeaker is measured on the basis of its ability to reproduce a signal without distorting or warping. When compared to other audio equipment, a loudspeaker lacks a lot in this. The frequency response of the amplifiers may vary less than 0.1 dB whereas for loudspeakers it is around +3 dB and -3 dB of ideal linearity.

Piezoelectric speakers are the ones which are frequently used as beepers in watches and other electronic equipment. In less expensive sound systems it is used as tweeters. Examples of such devices are computers and portable radios. However, such uses are quite vast because of its low cost.

Overload cannot bog down a piezoelectric speaker, so they get an advantage over regular loudspeakers. Overload is capable of destroying the voice coil of a usual loudspeaker, but that doesn't happen to the piezoelectric ones. They have an inherently efficient electrical load, so the need for a complex external crossover is less.

One of the main disadvantages is that their frequency response, more often than not, is quite substandard in comparison to other prevalent technologies. The oscillation during the drive of capacitive loads can sometimes lead to distortion or damage of the amplifiers. This answers the question why piezoelectric speakers are generally used in single frequency or non-critical applications.

There are special circumstances where the piezoelectric speakers are used both as input and output devices. Sonar application is one such example. There the use is to generate underwater sound. This is the output version and for input the use is to act as a sensing part of underwater microphones. They are quite advantageous in this regard. Actually, their usefulness is much higher than that of the ribbon based instruments.

Ceramic is nowadays used as the material for piezoelectric speakers. The compact size in fact helps further miniaturization for PDAs, digital cameras, 3G mobile phones, and other such appliances. All standard dynamic speakers use the magnet to function, whereas the compact size would lessen the thickness as well as the weight. The weigh loss can be up to 30 to 50 per cent. The power utilization will also be low, around half of the original. This will be less costly in the long run.