Echo chamber

An echo chamber is a hollow enclosure used to produce reverberated sounds, usually for recording purposes. For example, the producers of a television or radio program might wish to produce the aural illusion that a conversation is taking place in a large room or a cave; these effects might be accomplished by playing the recording of the conversation inside an echo chamber, with an accompanying microphone to catch the reverberation. Nowadays effects units are more widely used to create such effects, but echo chambers are still used today, such as the famous echo chambers at Capitol Studios.

In music, the use of acoustic echo and reverberation effects has taken many forms and dates back many hundreds of years. Medieval and Renaissance sacred music relied heavily on the composers' extensive understanding and use of the complex natural reverberation and echoes inside churches and cathedrals. This early acoustical knowledge informed the design of opera houses and concert halls in the 17th, 18th and 19th centuries. Architects designed these to create internal reflections that would enhance and project sound from the stage in the days before electrical amplification. Sometimes echo effects were the unintentional side effect of the architectural or engineering design, such as for the Hamilton Mausoleum in Scotland, which reportedly has the longest reverberation of any building.

Developments in electronics in the early 20th century—specifically the invention of the amplifier and the microphone—led to the creation of the first artificial echo chambers, built for radio and recording studios. Until the 1950s echo and reverberation were typically created by a combination of electrical and physical methods.

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