Audiogearreviews.com Glossary
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Glossary Category - DVD Players
AM
Amplitude Modulation. A method of radio transmission which sends information as variations of the amplitude of a carrier wave.
AM Presets
Preset memories for AM radio stations.
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.
Amplifier (Audio)
A device that increases the output level of the signal it receives without changing the sonic characteristics of that signal. While typically used to describe a device that drives speakers (transducers) it does define any device that increases the level of the audio input signal.
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
Battery (B-)
The ground terminal post of the battery.
Battery (B+)
The positive termial post of the battery. It also refers to the electrical connection that is always energized with 12 volts + from the battery.
CD
Developed by Philips and Sony, the compact disc was first commercially implemented digital medium for storing digital audio data. The physical size of the disc is 12 cm and store up to 700MB of data.
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 (Digital)
A crossover that filters the audio bandwidth with algorithms in the digital domain. It is located between the digital decoding of a CD or DVD and the analog converted output.
Crossover (Electronic)
A crossover that separates the audio signal in the pre-amplifier stage. It can be a stand alone device or incorporated in an amplifier, signal processor or source unit.
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 Point
The frequency point at which the crossover affects or filters the audio signal.
Current Draw
The amount of current of an electrical device from vehcile's electrical system.
Detachable Face
The removeable part of the source unit's face plate.
Differential Inputs
An audio signal delivery system that reduces noise. For each input signal there are two signal wires. A third connector allows the signals to be referenced to ground. The audio output is the difference in voltage between the two wires: any voltage (noise) common to both wires is removed.
Digital
The method of storing, processing and transmitting information through the use of distinct electronic or optical pulses that represent the binary digits 0 and 1.
DIN
DIN, (a German Institute for Standardization) used to describe the stardard size of radio mounting location is vehicle
DVD
Digital Video Disc. Capable of storing 4.7 GB or 8.5 GB for single or dual layers respectively.
Efficiency (Amplifier)
The ratio between the amounts of power consumed versus the amount of power produced. Efficiency depends on many factors, including but not limited to, battery voltage, amplifier load and impedance load of the speakers.
FM
Frequency Modulation The process of varying the frequency of an RF carrier wave in accordance with the amplitude and frequency of an audio signal.
FM Presets
Memory preset for FM radio stations
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.
Gain
The ratio of the signal output of a system to the signal input of the system.
Gain Control
Adjustment device use to match the ouput of an audio device to the input sensitivity of another audio device.
Ground
Refers to the metal chassis of the vehicle that is electrically connected to the B- of the battery. Also refers to any wiring that connects back to the B- of the battery.
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.
IM Distortion
Intermodulation Distortion. The ratio, in dB, of the total rms signal level of harmonic sum and difference distortion products, to the overall rms signal level.
Impedance
This is the total opposition to the current flow of an Alternating Current (AC) within a measured system. Measured in Ohms.
Input Sensitivity
The range (in volts or millivolts) that a electronic device is designed to accept.
MP3
Originally developed in Germany in 1991 by the Fraunhofer Institute, MP3 (MPEG Audio Layer 3) is an audio compression technology that is part of the MPEG-1 and MPEG-2 specifications. MP3 compresses CD quality sound into significantly smaller file size with near the same music fidelity.
MP4
MPEG-4 is a file format for compressed video.
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.
Polarity
The orientation of the positive and negative connections of an audio signal.
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.
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.
Satellite Radio
Digital music programming without commercials. Signals come from satellites in high fidelity digital format.
Seek
A source unit control that selects the next track on a CD, DVD or Satellite Radio or the next strong station of AM or FM radio.
Slew Rate
The maximum rate which an amplifier's output can change, generally expressed in V/µs. This is the speed of the amplifier.
Slope Rate (dB/Octave)
Is the rate at which a crossover attenuates or filters an audio signal.
Source Unit
A device that produces the audio signal for a system from a source material of format like CD, DVD, MP3, WAV, AC3,
Source Unit
The car audio component that decodes and plays the the source material.
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.
Track
This is the smallest division on DVD-Audio Video CDs, and CDs and usually equates to a single song.
TV Presets
Memory presets for television channels
Vapor Ware
Product displayed and introduced to the market that does not exist.
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.
Volume Control
The control that adjusts the overall output level of a system. Not to be confused with a gain control.
WAV
Uncompressed file format used by CD's to digitally store music.
Xover
See Crossover
