Automation is a very powerful tool, which can be applied in a variety of ways. The days of digital era are filled with unreal level of automation, as DAWs can record minute alterations and now offer automation for pretty much any parameter.
One of the best things about automation is the many ways it can be used. Some producers who really favor compression will squash it with the compressor and then automate dynamics back into the track. Automated pans between sections of a song, track mutes, effects, routing, and on the stereo bus are other ways automation can be used in a mix.
DAWs offer a level of automation like never before. Every DAW varies but they all offer essentially the same features for setting automation. The two main ways for setting automation would be drawing the envelope or playing through the track and using the mouse to ride the fader, simulating the experience of an analog machine.
Write: Writes automation as the track is played. Creates an editable envelope with break points that represent fader movements. In some DAWs it will switch to another mode immediately after recording to avoid incorrect overwrites.
Trim/Read: Existing envelopes are applied, but on-screen controls don't move. This allows a track's controls to be used to make overall changes. Fader movements are not recorded, but instead are made relative to the envelope. For example, you can retain the automation dynamics and control the overall volume with the volume fader.
Read: Safe Mode for automation. Plays previously written automation. Does not write or remember.
Latch: Latch will play through previously written automation and unless changes are made, it performs like the read function. Upon the first change to the envelope it will begin to write until playback stops.
Touch: Similar to latch, but stops making envelope changes when they are no longer adjusted.
There are as many applications for automation as there are creative engineers. It has been a valuable mixing and recall tool for some time, and the digital revolution has added an element of automation like never before.
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