Delay: A History & Analysis

December 21, 2014 by Toby Walton

Delay is a commonly used audio effect. In short it records an input signal, to some kind of storage medium, and then plays that recorded signal back after a set period of time. It can be used to enhance a mix, create a fuller sound and even allow looping.

The first artificial time delays were used to enhance the quality of radio broadcasts. They utilized telephone lines, by transmitting a signal over a phone line to somewhere hundreds of miles away, and then back again. By transmitting the signal over a very long distance, they would achieve a few milliseconds of delay which would then be mixed with the original signal.

During the 1950’s magnetic tape was utilised to create the first slapback delay effect that became a trademark of the rockabilly sound. Gradually innovators such at Charlie Watkins and Ray Butts developed units that gave a lot more flexibility such as the Echosonic (1952), the Watkins Copycat (1959) and the Maestro Echoplex (1959). They employed the used of electric motors, to feed a tape loop through different mechanisms, which modified the signal according to how the parameters were set. However the thin magnetic tape was not very durable and would have to be replaced from time to time.

A more profound method for creating delay during the 50s and 60s was invented by Ray Lubow. The units used a metal oil can to store an electric signal, and a rubber belt is then driven to spin a flywheel fitted with a pick up inside the can. Acting as the recording head, the pickup moving through the oil with give it a unique sound, with warbling vibrato and a blend of reverb.

During the 1970’s the much more durable solid state delay units became available, and were a brief mainstream alternative to tape delay units. They utilised analog bucket brigade delay (BBD) circuits which would pass the signal along a line of capacitors. Upon entering the unit the signal would be split, one routing straight to the output (dry), and the other going through the capacitors (wet), the capacitors would slow the signal down and then be mixed with the dry signal, creating a delay. Although being described as analog, the bucket brigade delay is actually a digital/analog hybrid.

These BBD circuits eventually found their way into compact pedals by the mid 1970s. They were usually limited to around a 300ms delay, and renowned for high frequency loss and a high noise floor particularly when set for longer delay times. However, the filtering effect of this high frequency loss and the addition of noise added a certain quality to the sound of the pedals which people loved.

At the same time, new digital delay lines were becoming available, but were very expensive. This meant that BBD delays remained incredibly popular until the development of a cheaper and mass-manufactured digital technology. The digital systems brought with them longer delay times and increased features. They function by putting the signal through an analog-to-digital converter, which is then recorded into a storage buffer. It is then played back based on parameters set by the user.

Today there are an extensive amount of delay plug-ins available, and most DAW’s come with a number of different types, including tape delay emulations, stereo delays, and sample delays. They work on the “same principles, just without the moving parts, additionally, they can sound pretty close to any of the other styles or be totally unique like OhmBoyz.” (Tidey, 2014).

The most common delay parameters are:

  • Delay time - time before repetition.

  • Tempo Sync - repetitions in time with the BPM.

  • Feedback - how many repetitions.

  • Wet/Dry - the mix of the two signals.

  • LFO - delay time modulation.

  • Depth - range of LFO modulation.

  • Filter - A hi and lo cut filter, included in the feedback circuit therefore increases in intensity with each repeat.

Some Plug-ins also include:

  • Distortion level - amount of saturation.

  • Groove slider - how close every second repetition is.

Delay forms the basis for many mixing techniques and effects including:

  • Phaser

  • Flanger

  • Chorus

  • Doubling

  • Slapback

  • Echo

  • Reverb

The first notable use of magnetic tape to create a delay, can be heard on How High The Moon - Les Paul, Mary Ford (1951). Les realised “that the space between the record and playback heads of a tape recorder could be used to create a Tape Delay. Later, to increase the delay time, he tied two tape recorders together” (Madigan). Les Paul’s guitar sound on How High The Moon was one of the first recordings to feature the ‘Rockabilly’ sound that later became popular, and was incredibly successful at grabbing peoples attention due to the novel and innovative nature of the sound. Coupled with his other groundbreaking techniques, Paul achieved an incredibly full and thick sound.

Around 1954 (Peneny, 2014) Sam Phillips used this technique to great effect. Phillips set up two Ampex 350 recorders, "By 1954 Sam Phillips had upgraded his equipment and installed two Ampex 350 recorders: one a console model and another mounted behind his head for the tape delay echo, or slapback” (Peneny, 2014). He created the slapback by splitting the signal in two, one to the modified recorder (wet), and to the console (dry).Phillips had set the playback head to play the tape back a fraction of a second later, and then this was to sent into the console where he would mix the two signals together, and finally send it out into the unmodified recorder. Phillips achieved a delay of around 45 to 110 milliseconds (Staub, 2013), according to the speed he set the tape to, and by only allowing it to repeat once Phillips managed to make “2 or 3 musicians sound like an 8 piece band!” (Trent, 2014).

This sound became a signature of Phillips’ studio, Sun Studio and many sought after the thick and fattening quality the effect brought to audio. A clear example of Phillip’s more experimental longer delays can be heard on Blue Moon Of Kentucky sung by Elvis Presley, the B-side to That’s All Right, where the slapback can be heard with a shorter delay time.

Used in a DAW Echo is a form of delay, that adds a sense of space, and emulates the original analog delays by introducing a degradation of the sound with each repeat and an element of distortion. In contrast to the slapback delay, echo is used to create longer delays, usually between 120 and 300 milliseconds. It can be used for anything from from dub delays to extend vocal phrasings and “create an interesting and intriguing sound that was not originally there.” (Staub, 2013).

Mix engineer Jamey Staub often uses echo synced to an 1/8th note, to create a fuller sound and harmonies as the vocal develops, then can clearly be heard on Freak Like Me by Adina Howard and has been very effective at using delays to enhance the mix.

During the 1970’s, Osbourne ‘King Tubby’ Ruddock, was also creating tape loops of his own much like Les Paul and Sam Phillips, but made much longer and repetitive delays leading to the invention of dub. “Tubby began to experiment with special "versions", dropping the vocals in and out, filtering the rhythm, or feeding tracks through his own custom-built loop-echo and spring reverb units.” (Green, 2002). Dub is one of the earliest forms of the ‘remix’ and predominantly uses delay to creatively reshape records. An example of this is King Tubby’s, Everybody Needs Dub, in which Tubby utilises delays to bring the keys, organ, guitar and vocals in and out of the arangement. It is a very effective way of creating a more interesting track, and centering the focus around the bass and drums which were the key elements to the sound system culture of the time.

Tubby was one of the key innovators of this genre, alongside Lee “Scratch” Perry, who utilised a Roland Space Echo RE20 for his delays which can be heard on his extensive repertoire.

Today, longer delays like those used by Tubby and Perry, are used in popular music as a delay ‘throw’, and its generally synced to a 1/4 or 1/8th note. This technique is often used to fill dead space or when a vocalist takes a break, or at the end of a phrase; Engineers will use a delay to fill it in. An example of this is in Just The Way You Are by Bruno Mars (2010). Up until the chorus Mars’ vocal follows quite a fast rhythm, but when it gets to the chorus, Mars’ vocal becomes very broken up and is followed by a couple of seconds of instrumental between each phrase. The engineer has filled the mix out and kept it interesting by using a filtered 1/4 note delay for the last word of each phrase, allowing it to repeat twice. The engineer goes one up on this in the last chorus and has the delay panning from left to right giving it even more sonic interest.

In the same vain, delays are used to emphasize specific words that are important. “Using a delay helps to emphasize that importance.” (Smith, 2013). This could also be another factor that the engineer took into account when adding the delay to Mars’ vocal.

In contrast to the hardware or D.I.Y units used by that of King Tubby, Les Paul, and Sam Phillips, delays used in contemporary pop music are most likely applied with the use of a DAW.

In modern pop music, the slapback delay is often used to and brightness and a sense of space to a vocal, and help to thicken it up.

“For a thicker vocal sound, don't just add reverb and delay on busses. Try adding them directly to the channel and then following that with some compression to really pull the elements together. Slap-back delay (with very fast delay times) is a perfect candidate for this kind of thing. It's also important to keep release and feedback times short to avoid making a mess.” (SoundonSound, 2011).

This is a common technique used in genres such as hip-hop, where the vocal needs a sense of space, but needs to sound very up-front. The delay is usually very tight with zero feedback and set to around 50-60ms. It can be described as making it sound like the vocal is recorded in front of a reflective wall.

One track that uses this technique is Days Are Gone by Haim (2013). This type of slapback can be clearly heard in the vocals of the first verse. “This kind of effect is always a popular choice when you want to give any vocal a slightly alternative 'recorded in a garage' vibe, and in this instance I'd probably go for a delay time of around 50-60 ms myself.” (Senior, 2014).

Although it is similar to the technique used by Les Paul and Sam Phillips, the modern use of slapback within popular music seems to be used as more of a mixing trick, rather than to give the music a certain recognisable sound, like that of ‘rockabilly’ discussed earlier. Again, the effect is likely to be applied using a DAW where the engineer can have maximum control.

In conclusion, it seems that the use of delay has now become one of the main effects in an engineers toolkit, probably owing to the fact that they are incredibly easy to use within a DAW, and an engineer no longer needs expensive hardware or to build their own tape loop. It is also easy to see that as the technology has progressed over time, delay is no longer exclusively used as a creative effect, but has become invaluable as a mixing tool.

  • Default-avatarby Fectoper

    Could you please include the list of cited references or links to them? Thanks!

  • Default-avatarby Garry Margolis

    Interesting summary. The Cooper Time Cube, developed by Duane Cooper and Bill Putnam Sr. and released by UREI in 1971, included two different acoustical delay lines, with delays of 28 and 30 milliseconds. Universal Audio has a plug-in that emulates it.

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