The polar pattern of a loudspeaker.
A loudspeaker diaphragm that is coupled directly to the surrounding air mass of the listening room.
A loudspeaker diaphragm that is coupled to the surrounding air mass by an acoustic impedance matching transformer; that is, a horn.
An unpowered loudspeaker cone, placed in the port of a vented enclosure system. Also called a drone cone, or a slave cone.
Type of microphone incorporating a small radio transmitter to give reception at short distances without the need for cables.
Memory designed so that the location or 'address' of a given piece of information is independent of the information stored.
The instantaneous spreading apart of air particles during the negative going half cycle of a sound wave. The opposite of condensation.
An amplifying section in a tape recorder that prepares an audio signal for application to the record head, and bias current to the erase head.
A transducer whereby the state or configuration of the recording medium is changed in conformity with the signal.
A head on a tape recorder that performs both recording and playback functions.
Time taken for a limiter or compressor to return to its quiescent state on removal of the high level signal.
Device for transforming an alternating current into a direct one.
The mixing from a multitrack recording to produce a mono, stereo, or quadraphonic recording as a production master.
That magnitude of a complex sound that produces a sound-level meter reading equal to the reading that results from a sound pressure of 0.0002 dyne per cm at 1 kHz. Also called reference sound level.
A standard level, such as O VU, + 4 dBm, O dBV, to which other levels may be compared.
A single frequency tone, recorded at the head of a tape and used for alignment purposes when the tape is replayed at a later date.
Sound waves that reach the listener after being reflected from one or more surfaces.
A return of energy due to the wave striking some discontinuity in its supporting medium.
The change of direction, or beriding, of a sound wave as it passes from one medium to another.
Device which can store a certain number of bits, usually only temporarily (c.f. Memory).
An increase in amplitude when two sound waves combine additively.
The ability to judge one pitch by reference to another. Total lack of this ability is "tone deafness."
A device, operated by an electric current, and causing by its operation abrupt changes in an electrical circuit (making or breaking the circuit, changing of the circuit connections, or variation in the circuit characteristics).
The time it takes for a signal processing device, such as a compressor or expander, to return to its normal gainbefore-threshold, once the applied signal is removed or attenuated.
Opposition to a magnetic force. Reluctance is analagoys to resistance in a purely electrical circuit.
The magnetization left on a tape when a magnetic force is removed. Remanence is measured in lines of flux per quarter inch of tape width. Also called remanent flux.
A device used to translate electrical signals into sound waves.
The frequency response of the post-emphasis circuit in a tape recorder. The C.C.I.R. and the N.A.B. have both published recommended reproducing characteristics.
A transducer whereby the signal is re-created from a recording.
The magnetization remaining in a magnetic material once an applied magnetic force is removed.
That property of a substance which restricts the flow of electricity through it, associated with conversion of electrical energy into heat. Measured in ohms.
An electronic component that opposes current flow.
A condition resulting from the combination of the reactances of a system, in which a response to a sinusoidal stimulus of constant magnitude reaches a maximum at a particular frequency.
A resonant condition that is a function of the dimensions of a room.
The increase in amplitude that occurs at the resonant frequency.
Denotes a tone that is produced when two notes one fifth apart and an octave higher than the desired note are sounded to produce the desired pitch; a mode of generating synthetic bass.
A measure'of a magnetic tape's flux density after a saturation-producing magnetic field has been withdrawn.
The presence (persistence) of sound at a given point due to repeated reflections from walls, ceiling, floor, furniture, and occupants in a room.
Can be used to make vocalists sound better, but also applied in varying degrees to instrumental sounds. Short single delays added to the original give overdubbing effects, sounding like two voices or instruments in unison. Several short delays can make two or three voices sound like a chorus. Longer delays give echoes. Echo plates and spiral steel springs having transducers to impart and pick up sound vibrations have been the standard means of obtaining these effects. Electronic delay lines are also used. These consist of up to several thousand electronic capacitors connected in line in an integrated circuit. The signal is sampled at three times its highest frequency, and a charge corresponding to these samples is passed down the line. Their rate of progress is determined by pulses generated by an external clock. Thus the total delay can be altered by changing the clock frequency and multiple delays are obtained by tapping off at various points along the line. A mixture of various types of delay and reverberation applied at different points and to different instruments can often be found on the same record. Reverberation period The time required for the sound in an enclosure to decay to one millionth (60 dB) of its original intensity.
The difference between the level of a plane wave that produces in a nondirectional transducer a response equal to that produced by the reverberation corresponding to a 1-yard range from the effective center of the transducer.
Any electronic or acoustical device used, to simulate the natural reverberation of a large concert hall, or to produce a reverberant effect.
For a given frequency, the time required for the average sound-energy density, originally in a steady state, to decay to one millionth of its initial value after the source is stopped (i.e. 60 dB).
Post-synchronization in the same language as the original but with a different artist.
Standard disc-recording curve specified by the Record Industry Association of America.
Type of microphone in which currents are generated by the movements of a metal ribbon suspended in a magnetic field.
A high-frequency speaker, often horn-loaded, in which a stretched, straight, flat ribbon is utilized instead of a conventional voice coil.
Device which may be used to produce sum and difference frequencies of two signals applied to the input.
The interval between the instants at which the instantaneous value of a pulse or of its envelope first reaches specified lower and upper limits, namely 10% and 90% of the peak value unless otherwise stated.
The effective sound pressure taking into account both positive and negative pressures in a system. The squares of the compression and the refraction of a wave are added and the average taken.
The rate at which a frequency response curve decreases in amplitude; usually stated in dB per octave or dB per decade.
Memory having fixed contents which cannot be altered, used to hold microprocessor programs, tables etc.
The properties of a room that affect the quality of a sound source in the room. (i.e., reverberation, resonance modes, etc.)
Increases in amplitude at resonant frequencies that are a function of the dimensions of a room.
The distinctive acoustical characteristic of a particular room or concert hall. The characteristic ambient sound of a room or concert hall.
The point at which the transfer characteristic of a compressor or expander intersects the unity gain curve.
A low-frequency vibration originating from a vibrating electric motor in a turntable.
A low-frequency filter circuit designed to minimize or to eliminate rumble interference.