Delay

In audio production, a delay is an electronic device designed to store a signal for a specified period of time and then release it, thereby delaying the signal relative to other parts of an audio program. Delays are often used to create echo effects, where a particular signal may repeat several times, with each repeat being lower in level than the prior one. This application goes back many years to a time when delays were only able to be accomplished with tape recorders (see WFTD Tape Delay). Later, analog circuitry was developed that could store signals long enough to be useful as a delay. This often involved a complex process of dumping the signal from one circuit with a finite amount of storage into another, and so on. Some of these early designs were thus known as “bucket brigade” circuits because they pretty much worked like an old time fireman’s bucket brigade where water would be passed in buckets from person to person in a long line between the source and the fire. The big downside of these units was that it cost a lot to build one with enough bucket brigades to amount to any length of time, and the sound quality sometimes degraded as the signal was passed along, which was exacerbated when regeneration was applied to achieve multiple repeats. Ultimately delays became most flexible and useful when digital technology became practical. In a digital delay the signal is simply stored in memory chips until it is needed. The longer a signal needs to be stored, and the higher the sample rate and bit depth, the more memory is required, so early digital delays tended to suffer from some of the same problems as their analog counterparts. It wasn’t long, however, before digital delays could capture a nearly perfect recording of a signal and store it for minutes if necessary. Delay technology is at the core of most time based effects such as flangers, chorus units etc. They have also been widely used in broadcast applications over the years to provide a few seconds of delay to “live” broadcasts. These few seconds can be used by an attentive engineer to “bleep” out things like curse words, etc.