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Magnetic Shielding

Also called magnetic compensation (which is usually a more accurate description). A means of restricting the radiation range of the stray magnetic field from a drive unit’s permanent magnet which might otherwise interfere with the correct operation of moving-coil meters or CRT television monitors. While it is possible to enclose a magnet in a soft-metal case to prevent a stray magnetic field this becomes very expensive for large magnets, and so a more common approach is to affix additional small external magnets with opposite polarities to cancel out the unwanted stray field.

MADI

Multichannel Audio Digital Interface. Originally specified by the Audio Engineering Society (AES) as AES10 in 1991. This unidirectional digital audio interface shares the same core 24-bit audio and status data format as AES3, but with different 'wrapping' to contain 56 or 64 synchronous channels at base sample rates, or 28/32 channels at 96kHz. It can be conveyed over unbalanced coaxial cables, or via optical fibres.

m

Abbreviation for milli, meaning a multiplier of 1/1000 (one thousandth). Used as a prefix to other values to indicate magnitude, eg. 1mA = 0.001A.

LUFS

The standard measurement of loudness, as used on Loudness Meters corresponding to the ITU-TR BS1770 specification. the acronym stands for 'Loudness Units (relative to) Full Scale. Earlier versions of the specification used LKFS instead, and this label remains in use in America. The K refers to the 'K-Weighting' filter used in the signal measurement process. (See this article on the loudness metering concept.)

Loudness Wars

The practice of trying to make each new commercial music release sound subjectively louder than any previous release, on the misguided notion that louder is more exciting and results in more sales. A relationship between the average loudness of 45rpm singles and sales was noticed in America from jukebox plays, and that led to the first loudness war. However, the advent of the CD really ramped up the situation, with music becoming ever-more dynamically compressed to squeeze the average level higher and higher towards the 0dBFS peak level. This desctructive trend is, thankfully, now being slowly reversed with the ubiquity of loudness normalisation adopted by most online audio streaming services and broadcasters.

Loudness-Normalisation

The practice of matching the perceived loudness of different material to a given target loudness value. To accommodate varying peak levels, the medium requires an approporiate headroom margin. Loudness-normalisation is now the default form for HDTV broadcasts, as well as most audio streaming services, although the target loudness level currently varies between different platforms. Loudness-normalisation is measured using the LUFS or LKFS scale. (See LUFS, Peak-Normalisation, Mastering, Loudness Wars).

Logic

A type of electronic circuitry used for processing binary signals comprising two discrete voltage levels.

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