In audio production automation refers to having things programmed to happen in real time during a mixdown. In the 1970′s, when big multitrack tape machines were becoming common, and overdubbing parts became a standard way of working, the process of getting a good mix became exponentially more difficult. No longer was the whole recording of a live performance where the musicians pretty much balanced their own levels. Many components were put in later and eventually it became trendy to do mixes at other studios optimized for that purpose, thereby causing the mix to have to be created from scratch. Anyone who has ever had the occasion to be one of the three or four people huddled over the mixer making adjustments during a manual mixdown can appreciate the benefits of being able to automate most of the process. Early automation systems were basic level controls. They were synchronized to the tape machine by some form of Time Code (not necessarily SMPTE) and would remember any moves the engineer made and then play the data back causing the level change to occur at the proper time (assuming the automation stayed in sync with the tape – not a given). They worked by either having motorized faders, where the motors could be controlled by the automation, or by using VCA’s (Voltage Controlled Amp), which was a much less expensive and cantankerous option. VCA’s, however, didn’t sound as pure as the passive fader with a motor attached so most successful systems were “moving fader” based. Later the quality of the VCA based systems rose (while the cost declined) and they became popular among smaller studios, but moving fader systems are still considered the best choice for analog. Not only because they sound better, but because the tactile feedback of physically moving faders is something many engineers prefer. During the 1980′s many other aspects of mixing began to be automated. Things like aux sends, panning, and eventually even EQ and compression could be put under computer control. Nowadays there are many analog mixing boards that are totally under digital control and virtually every parameter can be automated. Further, with the advent of the DAW, complete recall and automation of every aspect of a mix has become a standard.