Abbreviation for Digital Delay Line. Refers a device used to delay an audio signal. The terminology of “delay line” comes from the analog world, where circuits are devised to intentionally introduce certain amounts of delay into a signal. There are many applications for such a circuit, and many different types have been developed. In some cases they do involve very long lengths of wire – hence the term “delay line.” Even in early digital systems audio delays were sometimes created by passing the digitized audio through a series of small memory chips, with each one holding the signal for a finite (and small) amount of time.