Brooks RM 909 reviews Envelope

1) How a sound or audio signal varies in intensity over a time span.
2) How a control voltage varies in level over time controlling a parameter of something other than gain or audio level.

Critical Distance
The point a distance away from the sound source where the direct sound and the reverberant sound are equal in volume.

Brooks Hi Fi reviews Frequency Response
How sensitive an electronic device (mic, amplifier, speaker, etc.) is to various frequencies; often communicated with a graph.

Floor
1) An alternate tam meaning Range (a limit on the amount the signal is reduced when the input signal is low by an expander or gate).
2) A shortening of the term Noise Floor (the level of the noise).

Brooks RM 909 Binary
A numbering system based on two. In binary there are two symbols used ("l" and "0").

Engineer
1) A technician in charge of a recording session; Also called Recording Engineer.
2) A person with an engineering degree.
3) A person with sufficient experience in the field to be equivalent to the education one would receive earning an engineering degree.

Lift
1) To boost gain of audio at a particular band of frequencies with an equalizer.
2) An elevation device in the star trek series of TV programs.

Bottom
The bass frequencies (as in "needs more bottom end").