Audiogearreviews.com Glossary
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Glossary Category - Subwoofers
Amperage
The rate of flow of electricity through wire - measured in terms of amperes.
Ampere
The measurement of the flow of an electric current through a conductor.
Amplitude
The measure of how powerful sound waves are in terms of pressure or voltage.
Analog
Continuously variable audio signal that can take on any value within a given range.
Attenuation
The process of weakening or reducing the amplitude of a audio signal.
Audio Bandwidth
The audible frequency range of human hearing
Back Plate
The back of the speaker that is connected to the magnet and provide the return path for the magnetic energy of the motor structure.
Back Plate (Bumped)
See Bumped Back Plate
Basket (Speaker)
The part of the speaker (transducer) that supports the motor structur in a static position and keeps the drive elements in a pistonic movement path.
Bl
The motor strength of a speaker (transducer) in the magnetic gap. The strength is a result of the magnet material used, the configuration of the motor structure and the size of the magnetic gap. Measured in Teslas.
Bottom Plate
The plate located on the bottom of the magnet in a speaker (transducer) that provides the magnetic return path for the motor structure. It is also connected to the pole piece. (The Bottom plate and pole piece can be the same unit)
Bumped Back Plate
A back plate that has a bumped construction to increase clearance for the voice coil former that allows for greater excursion.
Capacitance
That property of a system of conductors and dielectric, which permits the storage of electricity when potential difference exists between the conductors.
Capacitor
An electronic device which stores energy and releases it when needed. Also used to direct high frequency energy to tweeters. Rated in Farads.
Cms
The speaker's (transducers) mechanical compliance (reciprocal of stiffness) measured in mm/N.
Crossover
An audio device that separates the audio signal into two or more bands for reproduction by different speakers
Crossover (Bandpass)
A device, circuit or algorithm that combines the functionality of a high-pass and low-pass crossovers to allows a band of frequencies to pass through while filtering (blocking) out frequency above and below the pass band.
Crossover (High-pass)
A device, circuit or algorithm that allows higher frequencies to pass while filtering out (blocking) lower frequencies.
Crossover (Low-pass)
A device, circuit or algorithm that allows lower frequencies to pass while filtering out (blocking) higher frequencies.
Crossover (Passive)
A crossover that filter the audio bandwidth of a speaker. This device is located between the amplifier and the speaker.
Crossover Point
The frequency point at which the crossover affects or filters the audio signal.
dB (Decibels)
Units of the measure of loudness. Decibles is the loudness of 1/10 of a bell right. This is a logrithmic scale.
Digital Ready
A marketing term to make customers think that speakers and amplifiers are capable of dealing with the dynamics of a digital source.
Efficiency (Acoustic)
See No
Frequency
Frequency is the measurement of the number of times that a repeated event occurs per unit time. In audio, it is the number of times a speaker oscillates (cycles) per second.
Fs
The resonant frequency of a speaker (transducer) or subwoofer measured in Hz.
Gap Height
The thickness or the top plate of a speaker (transducer) or subwoofer.
Hertz (Hz)
The measurement unit of an audio frequency that is defined by the number of cycles per second. Can also be referred to as the pitch.
ILS Rating
This is the power rating technique used by manufacturers to misrepresent their products power output capability the term “ILS” refers to “If Lightning Strikes” In reality; all ratings that are not governed by the CEA-2006 standard should be carefully examined.
Impedance
This is the total opposition to the current flow of an Alternating Current (AC) within a measured system. Measured in Ohms.
Inductance
The property of a circuit or circuit element that opposes change in current flow. This causes current changes to lag behind voltage changes. Measured in henrys.
Le
The voice coil inductance of the speaker (transducer) or subwoofer measuredl in mH.
Magnet
A ferrite material charged to maintain a constant magnetic field. Used as the motor for speakers (transducers) and subwoofers.
Magnetic Gap
The space between the inside diameter of the top plate and the outside diameter of the pole piece of a speaker (transducer). The tighter the gap (less distance), the greater the efficiency of the motor structure.
Mmd
The mass of the speaker cone (Diaphram) typically measured in grams.
Mms
The effective mechanical mass of a speaker (transducer) or subwwofer including air load measured in grams
No
The efficiency of the speaker (transducer) or woofer measured in percent.
Octave
The frequency bandwidth ranges defined by the interval of half or double of the starting frequency.
Ohms
The measurement unit that defines electrical resistance.
Phase
The phase of an audio wave relates the position of a feature, typically a peak or a trough of the waveform, to that same feature in another part of the waveform (or, which amounts to the same, on a second waveform). The phase may be measured as a time, distance, a fraction of the wavelength, or as an angle.
Phase (Out of)
When two audio signal do not sync exactly. This is a common occurance in car audio.
Polarity
The orientation of the positive and negative connections of an audio signal.
Polarity (Out of)
A situation when a two or more speakers are 180 degrees out of phase from eachother.
Power (RMS)
The continuous power that either an amplifier can produce into a give impedance load or a speaker (transducer) can handle in its recommended frequency range.
Protection (Optical)
A protection circuit that prevents damaging DC current from a tweeter. It called optical because it is usually a 12 volt light bulb.
Protection (Tweeter)
A protection circuit that prevents damaging DC current from a tweeter. Can be optical, fuse or a poly switch.
Qes
The electrical "Q" of a speaker (transducer) or subwoofer.
Qms
The mechanical "Q" of a speaker (tranducer) or subwoofer.
Qts
The total "Q" of a speaker (transducer) or subwoofer.
Resistance
Electric resistance: a material's opposition to the flow of electric current. Measured in ohms.
Restitor
A device, with electrical resistance, that is used in an electrical circuit for current control and efficient operation.
Revc
The voice coil resistance of a speaker (transducer) or subwoofer measured in ohms.
Rms (speaker)
The driver's mechanical losses, in kg/s.
Sd
The surface area of the speaker (transducer) or subwoofer usually measured in square inches.
Sensitivity (Speaker,tranducer)
The amount of acoustical output generated (measured in SPL Sound Pressure Level) when the speaker (transducer) is supplied with a fixed amount of power. It is typically measured with 2.83 volts of pink noise measured at a distance of 1 meter from the center point of the speaker (transducer) cone or dome. Measured in dB (Decibels of sound pressure)
Slope Rate (dB/Octave)
Is the rate at which a crossover attenuates or filters an audio signal.
Speakers (Seperates)
See Seperates (Speakers)
Spider
The accordion shaped material that is connected to the voice coil former and the basket of a speaker (transducer). Its function is to control and limit the motion of the speaker (transducer).
Spider (Progressive)
A spider where the corrugations are staggered such that the spring effect changes based on the position of the voice coil.
SPL (Sound Pressure Level)
The measure of loudness of a car audio system. Measured in dB (decibels).
Subwoofer
A low-frequency speaker (transducer) designed to reproduce the lowest frequencies in the audible bandwidth.
Surround
The part of a speaker that connects the cone or dome of a speaker (transducer) to the basket. They are generally made from rubber, foam or, in less cases, paper.
Top Gasket
The gasket mounted on the outer perimeter of the surround. The gasket protects the edge of the surround and can provide an air seal for a back mounted speaker (transducer) or subwoofer.
Top Plate
The metal plate located on top of the magnet in a speaker (transducer) that focuses the magnetic energy of the motor structure.
Total Harmonic Distortion (THD)
The measurement of the distortion of a signal in the acoustic or analog domain. It is usually referred to THD + Noise.
Transducer
A mechanical device that converts electrical signal into an acoustic (audible) output. Also referred to as a speaker
Vapor Ware
Product displayed and introduced to the market that does not exist.
Vas
The volume of air equvilent to the suspension compliance of the speaker (transducer) or subwoofer.
Vd
Volume displacement of woofer measured in cubic feet.
Voice Coil
The device inside a transducer that is electrically connected to the amplifier that attracts and opposes the stationary magnetic field produced by the transducer magnet to create motion of the speaker (transducer).
Voice Coil (Former)
The material that provides the support for the voice coil wire. Usually made from paper, Kapton, aluminum or Nomex.
Voice Coil Height
The height of the voice coil windings of a speaker (transducer) or subwoofer.
Volt
Basic unit of electrical potential. One volt is the force required to send one ampere of electrical current through a resistance of one ohm.
Xmax
The linear one way movement of a speaker (transducer) where the voice coil remains in the magnetic gap of the motor structure.
Xover
See Crossover
Zobel Impedance Network
Passive crossover network designed to compensate for the inductance rise of a speaker (transducer) or subwoofer that is created by the coiled wire of the voice coil.
