Файл: Sound Tech Terms Dictionary.pdf

M

magnetic film:  Audio recording tape manufactured using a base of the same physical film

stocks, e.g., 16mm, 35mm, etc., and which contains a magnetic area running longitudinally
down the film for the recording of an audio track or tracks.  Magnetic film is 3-5 mils thick, so
that the same length of film and magnetic film will be of equal diameters when wound on
reels.  Full-coat magnetic film has magnetic oxide applied across its entire width.  Striped
magnetic film can have one or more thin stripes of oxide applied longitudinally on the film
base.  There is usually one (wide) stripe containing a single track of audio (in the same size
and location as track-one of a 3-track), while another (smaller) stripe is placed on the opposite
side to make the film pack evenly when wound together, usually known as a balance stripe.
The balance stripe is sometimes used to record timecode from 

1

4

–inch or DAT timecoded

production masters.  Also called mag.  Not used since the advent of synchronized audio multi-
track recording.  See film soundtrack.

magnetic recording tape:  Most magnetic tapes have a mylar or polyester base with a thin

coat of magnetic material, usually gamma ferric oxide or chromium dioxide, but newer tapes
are double-layered which combine the good low-frequency response of ferric oxide and good
high-frequency response and low noise of chromium dioxide; the oxide is cured onto the base
and the tape is calandered.  The metal particles have a random orientation in unmagnetized
tape, but they are aligned into definite magnetic patterns by the magnetic field produced by
the recording head.  If all other factors are the same, the wider the track, the greater the S/N
ratio: doubling the track width improves the S/N ratio by 3dB.  Professional analog tape re-
corders are available with tape widths up to 2” and up to 24 tracks.  There is a thin guardband
of uncoated base tape between the tracks to yield improved channel separation, reduce cros-
stalk, and provide some tolerance for differences in head/track alignment among machines.
See Barkhausen effect, back coating, MOL, bias, domain, extinction frequency, scrape-flutter filter.

Magnetic tape comes in a number of widths and formats (all denominated in inches):

Tracks

Historical Width

Next Standard

Most Recent

24

2

1

16

2

1

1

2

8

1

1

2

1

4

4

1

2

1

4

1

8

 (cassette)

2

1

4

1

2

(DAT)

4

1

4

Quarter-track

2

1

4

Stereo (Half-track)

1

1

4

Mono

magnetometer:  A device for measuring magnetism and magnetic fields.  Useful for testing

whether or not tape heads need to be degaussed, and also for verifying the magnetic fields
generated by unshielded speakers.

magneto-optical disk:  See MO.

magnitude:  The portion of the frequency response or impedance of a device that represents the

amplitude is called the magnitude, as distinguished from the phase, which is the other part.
Precisely, the term magnitude only applies to complex quantities, i.e., quantities character-
ized by both a magnitude and a phase.  For noncomplex quantities, the term amplitude is
used.

M

mag-optical print:  A motion picture film that has both an optical soundtrack and magnetic

soundtracks so it can be reproduced in conventional theaters with optical sound equipment
and also in houses equipped with stereo magnetic sound.

mag stripe print:  A 35mm or 70mm print with magnetic oxide stripes painted lengthwise

down both sides of film, on either side of the perforations.  These formats are now obsolete.
See print master.

manual:  The keyboard(s) on an organ or harpsichord played by the hands, as opposed to the

pedalboard, which is a keyboard played with the feet.

map:  A table in which input values are assigned to outputs arbitrarily by the user on an

item-by-item basis, used as input to a mapper.

mapper:  A device that translates MIDI data from one form to another in real-time.  See MIDI

mapper.

mark-in/mark-out points:  In video synchronization and post-production, the timecode ad-

dresses selected by the editor as the beginning and end points of a loop.  The synchronizer
will stop master and slave transports at the mark-out point after each insert take, then auto-
matically return all machines to the mark-in point in preparation for another take.  Various
synchronizers automatically add pre-roll and post-roll times to the mark-ins and -outs, so it is
important to understand how each unit internally defines all of these locations.

mark/space ratio:  See duty cycle.

marry:  To print sound and picture onto the same strip of film, as on an answer or release print.

masking:  A subjective phenomenon wherein the presence of one sound will inhibit the abil-

ity to hear another sound.  See frequency masking.

master:  (1) A gain control on a sound reinforcement or recording console that controls the level

of a mixture of signals whose levels have been set by the individual channel pots.  A console
will have a master gain control for each output signal.  (2) The final version of a performance
which will be used for the production of copies in a film production, this is the master dub.
See APRS label system, bin-loop master, cut(3), direct metal mastering, direct-to-disc, edit master,
glass master, lacquer master, post-production, stamper, transfer, two-track, master tape, mastering
lathe.  (3) One device within a MIDI network or recording/dubbing chain which provides the
master clock.

master balance:  A message of the Universal System-Exclusive type used for controlling the

balance between the left and right outputs of a multitimbral synthesizer, in preference to ad-
justing individual channel balance.

M

master clock:  A clock signal which is sent from a master device to all slaves to maintain tape

position synchronization.  In this process, the master clock device sends a signal from a dedi-
cated word-clock output to a dedicated word-clock input on all slave devices over a separate
cable, typically terminated with a BNC connector.  Master clock generators are available at
various accuracies, measured in ppm (parts per million): The AES defines Grade 1 clocks as
having a long-term accuracy of ±1ppm and Grade 2 clocks as ±10ppm.  The IEC specifications
are Level I ±50ppm for “pro” equipment, Level II (consumer) accuracy at ±1,000ppm, and
Level III has inaccuracy measured in days.  It is important to be aware of the master clock
spec on digital mixers, as some are specified with IEC Level II clocks, making attachment to
high-resolution recorders problematic, and in this case, an external clock would be necessary
to provide sufficient timing accuracy.

See house sync, self-clocking, reference source, sync reference.

master controller:  In a MIDI network, the device which a musician plays in order to control

other devices in the network.  Typically a keyboard, but a master controller could also be
drum pads or some other MIDI generator such as a string or wind controller.

master dub:  See master(2).

master fader:  A fader to which the groups or channels in a mixing desk are connected.  It

normally controls the level of the stereo output from the desk.

mastering:  The stage between mixing and the pressing plant, where cuts are assembled in

the final order and the master(2) prepared for duplication:  song-to-song levels are equalized,
the stereo image is properly balanced, fade-ins and -outs and any crossfades are added, any
last-minute compression/limiting is added to even out the dynamic range of the compilation
as a whole, if necessary, additional effects such as some reverb to smooth any abrupt transi-
tions, and clean-up of all remaining noise: hum, pops, clicks, crackles, etc.  (Old) The com-
mon term for the process of transferring the musical signal from a magnetic tape, usually
called a master tape, to an acetate master disc, being the first step in the manufacture of pho-
nograph records from tapes.

mastering lathe:  A lathe bed and carriage mechanism (the actual cutting stylus or head, arm,

and armature).  Using a high-wattage amplifier to drive the cutting stylus, with a
pitch/depth control computer that controls the depth, width, and spacing of grooves being
cut, the mastering lathe makes the master lacquer disk from which metal parts and then vinyl
records are ultimately made.

master tape:  (Old) Records are usually made from tape recordings, and the edited tape from

which the acetate is cut is called the master tape.  It could be an original recording, but more
often it is a copy of original tapes.

matching:  See impedance-matching.

matching transformer:  Short for an impedance-matching transformer.  Used to interconnect

devices or cables of different impedances.  Necessary, for example, when using a low-
impedance mic with a guitar amp, which has high-impedance inputs.  The transformer in-
creases the energy transfer between the mic and the input, preserving the high-frequency re-
sponse in the signal.

M

matrix:  (1) A term used to describe any system which allows devices to be connected as

though they were arranged along the two axes of a grid, i.e., a structured form of patching.
For example, the VCS range of modular synths, where the outputs of the various modules are
connected to the left edge of a grid of holes, while their inputs are ranged along the top edge.
Electronic versions of a matrix are implemented in software.  (2) See matrixing.

matrixing:  Matrixing is the linear mixing of two or more signal channels at specific ampli-

tudes and phases to form two or more new signals.  These new signals can be combined in
similar ways to recover the original signals.  The circuit topology used for matrixing is called
a matrix.  Matrixing is a linear addition  of signals used to encode directional information,
e.g., Scheiber matrixing used in Dolby Surround-sound, and it is not the same as modulation.

matrix modulation:  A method of connecting modulation sources to destinations in such a

way that any source can be sent to any combination of destinations.

MAX:  A real-time MIDI processing and graphic programming environment.  Max software

was first developed at IRCAM and later commercialized by Opcode Systems.

maximum output level (MOL):  For an audio device such as a tape recorder, the MOL is gen-

erally taken to mean the output signal level that results in 3% harmonic distortion at low fre-
quencies and usually 3% intermodulation distortion at high frequencies.  Any higher signal
output than the MOL will result in rapidly increasing distortion, and is a function of both in-
put signal frequency and of the device itself.  MOL also applies to a specification for analog
magnetic tape.  The MOL for a tape is frequency-dependent; all magnetic tape saturates faster
at higher frequencies; it is also speed-sensitive: as the recording speed is slowed, the distor-
tion point is lowered.  MOL may be referenced to an absolute flux level, or to a test tape.  See
third harmonic distortion.

MCPS:  Mechanical Copyright Protection Society.  The UK equivalent of BMI/ASCAP.  See

also PRS.

MD:  See MiniDisc.

MDM:  See Modular Digital Multitrack.

meantone:  In tuning, the meantone system was a common technique used for keyboard in-

struments before equal temperament came into general use.  Meantone temperament is a tun-
ing in which the thirds are turned pure, and all of the fifths are one-fourth of a diatonic comma
too narrow.  All the whole tones are equal and are precisely half a major third, hence the
name meantone.  It provides for the pure intonation of the key of C

maj

 and those lying near it

at the expense of the more extreme sharp and flat keys, which is the reason why remote keys
were rarely used in keyboard works before the adoption of equal temperament.  There was,
for example, a pure F  and B , but these notes were out of tune when used as G  or A .

measure:  Also called a bar.  The space between two bar lines in music notation, suggesting a

unit of time.  Measured music has sections with a well-defined meter, and which can be easily
notated within bar lines.  Almost all western music of the past five hundred years is of this
type.

mega:  Prefix meaning “one million times the unit that follows,” e.g., a megawatt is one mil-

lion watts.  See M.

M

Melco:  See ProDigi.

memory requirements:  One minute of MIDI information takes up approximately 0.035MB of

memory, compared to about 10MB for CD-quality stereo digital audio (16-bits at 44.1kHz),
and over 34MB for 24-bit, 96kHz sampling precision.

merger:  A MIDI accessory that allows two incoming MIDI signals to be combined into one

MIDI output.

Meridian Lossless Packing:  See MLP.

metadata:  Generically, parameters which apply globally to a particular data transmission, as

opposed to the data actually carried in the transmission.  These data usually include type of
codec, number of channels, channel format, originating node information (in a network con-
text), type of data encryption, etc.  In Digital Dolby, metadata specifically refers to the pa-
rameters which travel alongside the audio in the Dolby Digital stream as auxiliary data.  The
metadata here provides scalable decoding information about the audio which can be inter-
preted in different ways by different receivers, allowing a producer to tailor a program’s mix
to the playback environment without requiring the medium to store multiple versions, e.g., a
5.1 mix and a stereo mix.

meta event:  See SMF.

meter:  The time signature of the music, i.e., how many beats are in each measure.

MCI:  Media Control Interface.  A multimedia specification designed to provide control of

onscreen movies and peripherals like CD-ROM drives.

mic-level:  The nominal output level of a microphone, usually -50dBv to -40dBv, as opposed

to line-level.  This corresponds to a few millivolts of power.

mic/line switch:  On a recording console, the two-position switch that allows the engineer to

select whether each module will control the mic-level signal from a microphone in the studio,
or the previously recorded track of a tape or other signal coming into the console at line-level.

micron:  A standard unit of length, equal to one millionth of a meter.  Used to specify very

small measurements, such as tape recorder head gap widths.