From m to Upper Toms  

m
1) This is the Greek letter “mu”, which is actually a forerunner of the English “M”, however, the lower-case “u” is often used in place of it because of it’s similar appearance.
2) This symbol is used for micro- (one millionth).
3) m s means two microseconds which is 2/1,000,000 of a second.

Unbalanced
A method of interconnecting recorders, amplifiers and other electronic gear using two-conductor cable.

Undo
A command in some computer software that reverses the last command entered.

Uni
A prefix meaning One.

Unidirectional
A pick-up pattern which is more sensitive to sound arriving from one direction than from any other.

Unison
Several performers, instruments or sound sources that are sounding at the same time and with the same pitch.

Unity Gain
No increase or decrease in signal strength at the output of an amplifier or device compared to the signal strength at the input.

Update
By Absolute Solid State Logic name for re-writing the settings for an automated console control.

Update Mode
A mode of operation of console automation allowing modification of the programming of a channel of a console so that when the slide of the fader is at a predetermined point (usually the point marked “0”) the gain variations (fader movements) last programmed in the computer will be in effect, but when the engineer moves the slide up or down from this point gain or loss is added to or subtracted from the programmed level.

Upper Midrange
The frequencies between 2 kHz and 6 kHz.

Upper Toms
Another name for rack toms (small to medium-size drums usually 10 – 14 inch diameter, that are mounted to a rack over the foot drum in a drum kit).