Glossary of Audio Terms: J - N
JACK: 1/4inch Audio connector can either be mono or stereo indicated by one band for mono to two for stereo.
JECKLIN DISK: A sound absorbing disk placed between two omni-directional microphones for stereo recording.
JITTER: Timing variations in various sampling clocks used throughout a digital audio system.
k: Abbreviation for 1000 (kilo). Used as a prefix to other values to indicate magnitude.
kOhm: 1000 ohms
LED: Light Emitting Diode.
LCD: Liquid Crystal Display.
LFO: Low Frequency Oscillator, often found in synths or effects using modulation.
LSB: Least Significant Byte. If a piece of data has to be conveyed as two bytes, one byte represents high value numbers and the other low value numbers, much in the same way as tens and units function in the decimal system. The high value, or most significant part of the message is called the Most Significant Byte or MSB.
LIGHTPIPE: A means of transferring digital audio using fiber optic cable from one audio device to another. Developed by Alesis
LIMITER: Device that prevents audio signal from going above a specified level irrespective of the input level. Very useful in making your master mix sound very loud and completely ruining the dynamics.
LINEAR: A device where the output is a direct multiple of the input.
LINE LEVEL: A nominal signal level which is around -10dBV for semi-pro equipment and +4dBu for professional equipment.
LOCAL ON/OFF: A function to allow the keyboard and sound generating section of a keyboard synthesizer to be used independently of each other.
LOOP: Circuit where the output is connected back to the input.
LOW FREQUENCY OSCILLATOR (LFO): An oscillator used as a modulation source, usually below 20Hz. The most common LFO waveshape is the sine wave, though there is often a choice of sine, square, triangular and sawtooth waveforms.
LOW PASS FILTER (LPF): A filter which attenuates frequencies above its cutoff frequency.
MADI: Multichannel Audio Digital Interface. Developed by AMS-Neve, SSL, Sony and Mitsubishi. Originally designed to carry up to 56 channels of audio via fiber optic cable. From large format digital console to digital multitrack. Been up dated for higher sample rates and up to 64 channels of audio over one cable.
mA: milliamp or one thousandth of an amp.
MB: Megabyte. 1,000,000 (one million) bytes of data.
MEG: Abbreviation for 1,000,000.
MEMORY: Computer's RAM memory used to store programs and data. This data is lost when the computer is switched off and so must be stored to disk or other suitable media.
MIC LEVEL: The low level signal generated by a microphone. This must be amplified many times to increase it to line level.
MICROPHONE: Equipment used to convert audio into electrical signal.
MICROPROCESSOR: Specialised microchip at the heart of a computer. It is here that instructions are read and acted upon.
MIDI: Musical Instrument Digital Interface. A standard format that allows digital musical instruments, computers etc to communicate with one another using a specified set of commands
MTC: MIDI Time Code; a MIDI sync implementation based on SMPTE time code.
MIXER: Equipment for combining two or more audio signals.
MONITOR: A reference speaker used for mixing. Lots of brands to choose from but one of the most widely used is Yamaha NS10, which of course is now out of production.
MONITOR: VDU display for a computer.
MONOPHONIC: One note at a time.
MOTHERBOARD: The main circuit board within a computer into which all the other components plug or connect.
MP3: Form of data compressed audio.
MULTI-SAMPLE: The creation of several samples, each covering a limited musical range, the idea being to produce a more natural range of sounds across the range of the instrument being sampled. For example, a piano may need to be sampled every two or three semitones in order to sound convincing.
MULTI-TIMBRAL: A synthesizer, sampler or module that can play several parts at the same time, each under the control of a different MIDI channel.
MULTITRACK: A device used to record multiple sound sources on to separate tracks. For example. Drum kit recording. Bass drum on track 1 Snare on track 2 HiHat track 3 etc
NAB: National Association of Broadcasters
NEAR FIELD (CLOSE FIELD): Speaker used to monitor audio close to the listener.
NOISE REDUCTION: System for reducing analogue tape noise or for reducing the level of hiss present in a recording.
NOISE SHAPING: A system for creating digital dither such that any added noise is shifted into those parts of the audio spectrum where the human ear is least sensitive.
NON-LINEAR RECORDING: Describes digital recording systems that allow any parts of the recording to be played back in any order with no gaps. Conventional tape is referred to as linear, because the material can only play back in the order in which it was recorded.
NORMALISED: Usually refers to patchbay configuration. Normalised means that the original signal path is maintained, until a patch cord is inserted and breaks the signal. Insert points for a console is a good example where this is used.
NORMALIZATION: Peak Normalization is a automated process that changes the level of each sample in a digital audio signal by the same amount, such that the loudest sample reaches a specified level.
NOTCH FILTER: Filter that passes all frequencies apart from any that are defined by the user which are then attenuated.
NYQUIST THEOREM: The rule which states that a digital sampling system must have a sample rate at least twice as high as that of the highest frequency being sampled in order to avoid aliasing. Because anti-aliasing filters aren't perfect, the sampling frequency has usually to be made more than twice that of the maximum input frequency.