Sound reproduction denotes the process of recording, processing, storing, and recreating sound, such as speech, music, or other sounds. When recording an acoustic scenario, one or more microphones are used to capture sound in single or multiple positions for a recording device. When recording electronical or digital sound sources, microphones are not necessarily required, since the recording devices can directly store the electrical or digital signals. The signals may be processed and stored, and finally made audible to a human listener with loudspeakers or headphones. Note that during this process many choices must be made in order to capture, process, and play back the sound. However, the unifying factor is the common endpoint of the chain, the human listener. This is a distinctive property of the field of communication acoustics compared to some other fields of acoustics. In communication acoustics, the sound is the desired signal, which brings some information or added value to the listener.
Historically, reproduction of sound has come a long way from the first phonograph built by Thomas Edison in 1877. A large variety of sound reproduction applications is currently in use, and they differ both in implementation and the purpose for which they were developed. We begin this chapter by discussing the needs and challenges faced in sound reproduction and continue to present various solutions and technologies for this purpose.