Delay (audio effect)
Delay effects can be created using tape loops, an approach developed in the 1940s and 1950s and used by artists including Elvis Presley and Buddy Holly.
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 such as 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.
[2] American producer Sam Phillips created a slapback echo effect with two Ampex 350 tape recorders in 1954.
[3][4] The effect was used by artists including Elvis Presley (such as on his track "Blue Moon of Kentucky") and Buddy Holly,[5] and became one of Phillips' signatures.
It is 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).
[5] Before the invention of audio delay technology, music employing an echo had to be recorded in a naturally reverberant space, often an inconvenience for musicians and engineers.
The presence of multiple taps (playback heads) made it possible to have delays at varying rhythmic intervals; this allowed musicians an additional means of expression over natural periodic echoes.
Electric motors guide a tape loop through a device with a variety of mechanisms allowing modification of the effect's parameters.
[14] Popular models include Ray Butts' EchoSonic (1952), the Watkins Copicat (1958), [15][16] the Echoplex (1959)[9] and the Roland Space Echo (1974).
The Binson Echorec used a rotating magnetic drum or disc (not entirely unlike those used in modern hard-disk drives) as its storage medium.
[21] An alternative echo system was the so-called oil-can delay method, which uses electrostatic rather than electromagnetic recording.
[22] Invented by Ray Lubow, the oil-can method uses a rotating disc of anodized aluminium coated with a suspension of carbon particles.
An AC signal to a conductive neoprene wiper transfers the charge to the high impedance disc.
As the particles pass by the wiper, they act as thousands of tiny capacitors, holding a small part of the charge.
A second wiper reads this representation of the signal, and sends it to a voltage amplifier that mixes it with the original source.
To protect the charge held by the particles and to lubricate the entire assembly, the disc runs inside a sealed can with enough of a special insulating oil[a] to assure that an even coating is applied as it spins.
Fender sold the Dimension IV, the Variable Delay, the Echo-Reverb I, II, and III, and included an oil can in their Special Effects box.
Ray Lubow himself sold many different versions under the Tel-Ray/Morley brand, starting out in the early sixties with the Ad-n-echo, and eventually producing the Echo-ver-brato, the Electrostatic Delay Line, and many others into the eighties.
Digital delay effects were initially available as expensive rack-mounted units intended for use in television and audio production studios.
[28] As digital memory became cheaper in the 1980s, units like Lexicon PCM42, Roland SDE-3000, TC Electronic 2290 offered more than three seconds of delay time, enough to create background loops, rhythms, and phrases.
Some systems allow more exotic controls, such as the ability to add an audio filter and modulate the playback rate.
Software implementations may offer shifting or random delay times, or the insertion of other audio effects in the feedback path.
Abundant main memory on modern personal computers offers ample delay time.
U2 guitarist the Edge uses delay while he plays arpeggios on electric guitar, thus creating a sustained, synth pad-like background.
Robert Fripp used two Revox reel-to-reel tape recorders to achieve very long delay times for solo guitar performance.
Mixing the original and delayed sounds creates an effect similar to doubletracking, or unison performance.
[36] With reverberation, there are multiple delays and feedback so that individual echoes are blurred together, recreating the sound of an acoustic space.
