N

NAB
National Association of Broadcasters

NAB CART

NAB
Magnetic tape format

NAB RECORDING LEVELS

NC
Noise Criterion

NBS.
US National Bureau of Standards

NEAR FIELD
The area close to a source of sound, where the listener hears more of the direct sound rather than reflected sound. Also termed Close Field.

NEAR FIELD MONITORS
Monitors that are placed near the listener.

NOISE
General term for any unwanted sound.

NOISE REDUCTION
The process of reducing any unwanted noise from a signal path.

NONLINEAR
1. A system where the relationship between one element (the cause) and another (the effect) is not linear, so that, for example, doubling the value of one does not cause a doubling of the other. 2. It is used to describe the ability of a digital system to play back parts of a recorded program in an order that is not dependent on the order the program was recorded in. An analogue tape system is an example of a linear system

NORMALISE
In a patch bay the top row of jack inputs is usually connected to the outputs of devices and the bottom row to the inputs. Normalizing the patch bay would ensure that the signal appearing at the top socket would automatically flow to the device connected to the bottom socket. Patch bays can be half or Fully Normalised.

NORMAL MODE

NORMALLING
See NORMALISE

NOTATION (MUSIC)
Representation of sound by graphical conventions.

NOTE SPACING
Referring to western notation. Music spaced to the note gives an absolute graphical representation of time values i.e. four semi-quavers (sixteenth notes) are allocated the same amount of space as a crotchet (quarter note). The disadvantages of applying this system is its printing inflexibility, and it is really only useful in very specific notation situations. This method provides more exact spacing than does Beat Spacing.

NTSC
National Television Standards Committee. It standardised the TV video standard used in Japan, North America and to some extent South America. It employs 30 frames per second and displays 525 lines per screen. Note that the method for encoding colour is different from the UK's PAL system.

NULL
A low or minimum point on a graph. A minimum pressure region in a room.

NYQUIST THEOREM
It states that in order to faithfully reproduce all frequencies present we must sample with a rate at least double the highest frequency present.