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Delay is an audio effect which records an input signal to an audio storage medium, and then plays it back after a period of time.〔(Lehman, Scott. "Effects Explained: Delay". 1996. ) Retrieved on June 30, 2006.〕 The delayed signal may either be played back multiple times, or played back into the recording again, to create the sound of a repeating, decaying echo. ==Early delay systems== The first delay effects were achieved using tape loops improvised on reel-to-reel magnetic recording systems. By shortening or lengthening the loop of tape and adjusting the read and write heads, the nature of the delayed echo could be controlled. This technique was most common among early composers of Musique concrète (Pierre Schaeffer), and composers such as Karlheinz Stockhausen, who had sometimes devised elaborate systems involving long tapes and multiple recorders and playback systems, collectively processing the input of a live performer or ensemble.〔(Gehlaar, Rolf. "Leap of Faith: A Personal Biography of Karlheinz Stockhausen's ''Prozession''. 1998. ) Retrieved on July 30, 2006.〕 Audio engineers working in popular music quickly adapted similar techniques, to augment their use of plate reverb and other studio technologies designed to simulate natural echo. In the late 1940s and early 1950s, several sound engineers began making devices for use in recording studios and later more compact machines for live purposes. Les Paul was an early pioneer; a landmark device was the EchoSonic made by American Ray Butts, a portable guitar amplifier with a built-in tape echo which became used widely in country music (Chet Atkins) and especially in rock and roll (Scotty Moore). Tape echoes became commercially available in the 1950s. An echo machine is the early name for a sound processing device used with electronic instruments to repeat the sound and produce a simulated echo. The device was popular with guitarists and was used by Brian May, Jimmy Page and Syd Barrett among others. One example is the Echoplex which used a tape loop. The length of delay was adjusted by changing the distance between the tape record and playback heads. Another example is the Roland Space Echo with a record and multiple playback tape heads and a variable tape speed. The time between echo repeats was adjusted by varying the tape speed. The length or intensity of the echo effect was adjusted by changing the amount of echo signal was fed back into the pre-echo signal. Different effects could be created by combining the different playback heads. Some models also included a spring reverb. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Delay (audio effect)」の詳細全文を読む スポンサード リンク
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