Glossary – G
The value of amplification that a signal obtains in passage through an amplifying stage or system. In electronics and audio gain is a unit of measurement used to mean the ratio of a signal output of a system to the signal input of the system. Gain is a term most commonly associated with amplifiers. An increase in signal power, voltage, or current by an amplifier, expressed as the ratio of output to input. Also called amplification. The amount of amplification (voltage, current or power) of an audio signal, usually express in units of dB (i.e., the ratio of the output level to the input level). For example, amplifying a voltage signal by a factor of two is stated as a voltage gain increase of 6 dB. Amplification factors are usually expressed in terms of power. The decibel (dB), a logarithmic unit, is the most common way of quantifying the gain of an amplifier. For power, doubling the signal strength (an output-to-input power ratio of 2:1) translates into a gain of 3 dB; a tenfold increase in power (output-to-input ratio of 10:1) equals a gain of 10 dB; a hundredfold increase in power (output-to-input ratio of 100:1) represents 20 dB gain. If the output power is less than the input power, the amplification factor in decibels is negative. If the output-to-input signal power ratio is 1:1, then the amplification factor is 0 dB.
The dB gain of a compressor, when the input signal level is below threshold.
In a compressor, the decrease in gain when the input signal level is above threshold.
Manually adjusting the gain in a signal path in an effort to decrease dynamic range.
The type of ferric oxide compound that is used in the manufacture of magnetic recording tape.
The adjustment of the magnetic gap in relation to the magnetic medium. a. Azimuth alignment. The adjustment of the orientation of the magnetic gap in relation to the direction of motion of the magnetic medium. b. Lateral alignment. The adjustment of the magnetic gap parallel to the plane of the magnetic medium and normal to its direction of motion. c. Pole face alignment. The rotation of the contact surface in a plane at right angles to the direction of motion of the magnetic medium in order to effect satisfactory contact over the full length of the gap.
The gap dimension, measured in the direction of tape travel.
Special amplifier circuit which has zero output unless the input level exceeds a chosen threshold level.
A circuit that operates as a selective switch and permits conduction over a specified interval.
A unit of measurement of a tape's remanent magnetization.
A copy of a tape. The original recording is a first generation tape. A copy is a second generation; a copy made from the second generation tape is a third generation, and so on.
A tone or signal source, such as an oscillator, frequency divider, or magnetic tone wheel.
A processed copy of a disc recording from which sounds may be reproduced by a mechanical or an electromechanical system.
Frequency correction device giving selective control in narrow bands and having slider controls which indicate the approximate response curve chosen.
A decorative and protective sound-transparent structure and/or mesh that forms the front surface of a speaker enclosure.
In a mechanical or electromechanical recording. The track inscribed in the recording medium by the cutting or embossing stylus. In a stereo disc, the two walls are cut at 45" angles from the perpendicular. Each recedes or advances independently of the other in sympathy with the recorded sound, the outer carrying the right-hand and the inner carrying the left-hand signal. When the signal in both channels is equal and in phase, the groove moves laterally, but when they are out of phase it moves vertically. Two generators in the pickup are so mounted as to respond only to one plane of motion of the stylus. Groove width thus varies, but it should not be less than a specified 1 mil. In practice 2 mil is the observed minimum to avoid groove-jumping with cheaper equipment.
The geometric form of the cross-section of a groove. It is defined in terms of the radius of the bottom of the groove (bottom radius) and the included angle between the walls of the groove (groove angle).
A point in any electrical system that has zero voltage, usually the chassis of any electrical component.
Spacing between tracks on a multitrack tape.
(Rifle microphone.) Type of microphone employing a long tube and being narrowly directional along the axis.
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