Originally derived from the term “recording session,” referring to the period of time when all the musicians were in the studio, the engineer was at the mixing console and the tape was rolling. Multitrack recording fragmented the original sense of this term by breaking complete “sessions” into individual segments in which only vocals, or drums, etc. were recorded at one time. Since then this word has been given different meanings by different audio software and hardware developers. Here are just a few examples.
In Pro Tools, a “session” refers to the master document that Pro Tools creates when you start a new project. The session file contains maps of all elements associated with a project, including audio files, MIDI data, and all your plug-in effects, edit and mix information. Included in the session file is a play list, which defines groups of regions arranged on each audio or MIDI track.
In the CD world a “multisession” CD is one on which individual tracks or files have been burned to the CD at different times – also known as track at once burning. The Orange Book CD standard defines this process. But a multisession CD can be “fixed up” – with a table of contents written – once all necessary material is recorded on it. If it’s an audio CD it can then conform to the Red Book CD standard – which is what all commercially produced CDs conform to.
On the Mackie dXb series of digital mixers, “session” is applied to a collection of fader and knob settings, plug-in effects instantiations, and any and all automation data performed by the mixer during one song, or one recording period. Note that no actual audio data is included in this definition. Mackie uses a “template” to describe preset initial fader, knob and effects values that allow you to begin a session with your preferred settings already in place.