एक लाउडस्पीकर एक विद्युत-ध्वनिक ऊर्जा परिवर्तित्र है, जो वैद्युत संकेतों को ध्वनि में परिवर्तित करता है। स्पीकर वैद्युत संकेतों के परिवर्तनों के अनुसार चलता है तथा वायु या जल के माध्यम से ध्वनि तरंगों का संचार करवाता है।

A loudspeaker is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A speaker system, also often simply referred to as a speaker or loudspeaker, comprises one or more such speaker drivers, an enclosure, and electrical connections possibly including a crossover network. The speaker driver can be viewed as a linear motor attached to a diaphragm which couples that motor's movement to motion of air, that is, sound. An audio signal, typically from a microphone, recording, or radio broadcast, is amplified electronically to a power level capable of driving that motor in order to reproduce the sound corresponding to the original unamplified electronic signal. This is thus the opposite function to the microphone; indeed the dynamic speaker driver, by far the most common type, is a linear motor in the same basic configuration as the dynamic microphone which uses such a motor in reverse, as a generator.