A

1. A crossover-is an electronic circuit that directs which frequencies go to which speakers. For example, since subwoofers are designed to best reproduce only the lowest frequencies, a subwoofer crossover (a low-pass crossover) allows only the low frequencies to pass through to the subwoofer. Freed from the task of reproducing heavy bass, your other speakers will rejoice by performing better and playing louder. You need crossovers so that you don't send unnecessary signals to a speaker (which could damage it).
Submitted on Saturday, April 12, 2008 3:43:42 PM

2. A is for amperes:a measure of electric current. How much is enough? (We like to say that having too much amperage is like having too much money.) Your car's stock alternator probably provides enough amperage to power a basic car audio system. But if you want to add multiple high power amplifiers, you might require some additional current, and the installation of a new alternator or stiffening capacitors (see this link section with answers to your questions for more on alternators and stiffening capacitors). Ampere is commonly abbreviated as "amp" (not to be confused with amplifiers), but sometimes it's "I." Electricity is like that.
Submitted on Wednesday, June 13, 2007 3:43:42 PM

3. A-B Test:
A test between two components. For example, a test between two different pre-amplifiers. For the test to be scientifically valid the levels should be matched.
Submitted on Wednesday, January 09, 2008 3:43:42 PM

4. A-B Test:A TEST BY WHICH AN OBSERVOR SUBJECTIVELY COMPARES THE PERFORMANCE OF TWO COMPONENTS OF THE SAME TYPE; FOR EXAMPLE, A TEST BETWEEN TWO DIFFERENT SPEAKIERS. FOR THE TEST TO BE SCIENTIFICALLY VALID, THE INPUTS, LEVELS, AND LISTENING CONDITIONS SHOULD BE MATCHED.
Submitted on Tuesday, April 08, 2008 3:43:42 PM

5. ABX Comparator:
A device that randomly selects between two components being tested. The listener doesn't know which device is selected.
Submitted on Tuesday, November 27, 2007 3:43:42 PM

6. ABX Comparator
A device that randomly selects between two components being tested. The listener doesn't know which device is being listened to.
Submitted on Tuesday, March 20, 2007 3:43:42 PM

7. AC-3
(audio coding 3) Dolby's digital audio data compression algorithm adopted for HDTV transmission and used in DVDs, laserdiscs and CDs for 5.1 multichannel home theater use and automotive surround application.
Submitted on Thursday, December 06, 2007 3:43:42 PM

8. Acoustic Coupling:
The interaction between two or more speakers stacked together in an audio system which may produce a sound different from (and often better than) the sound produced by the individual speakers.
Submitted on Thursday, January 11, 2007 3:43:42 PM

9. Acoustic feedback:
A phenomenon where the sound from a loudspeaker is picked up by the microphone or other transducer, like a phono cartridge feeding it, and re-amplifys it through the same loudspeaker only to return to the same microphone to be re-amplified again, etc.. Each time the signal becomes larger until the system runs away and rings, or feeds back on itself producing the characteristic scream or squeal found in sound (mostly, PA) systems. These buildups often occur at particular frequencies called feedback frequencies.
Submitted on Saturday, October 21, 2006 3:43:42 PM

10. Acoustic suspension:-A sealed or closed box speaker enclosure.
Submitted on Sunday, December 24, 2006 3:43:42 PM

11. Acoustic Suspension (enclosure):
A Sealed box system that uses the resistance of the internal air of a sealed enclosure to control the motion of the cone. Sometimes known as an infinite baffle type.
Submitted on Thursday, July 24, 2008 3:43:42 PM

12. Acoustics:-Sound is simply vibrating air. How fast, how much, and when the air is vibrated, determines what we will ultimately hear as sound. The science of this process is called acoustics. When a speaker cone (or anything else that has the ability to vibrate in the auditory range) moves forward, the air molecules in front of the cone are compressed, causing the molecules to form an accelerating wave forward. This continues to happen until the speaker cone moves in the opposite direction, which causes a rarefaction (or thinning) of the air mass between the speaker and the listener. This is the basic concept of how sound waves are produced.
Submitted on Saturday, October 20, 2007 3:43:42 PM

13. Active-A word prefacing certain circuits in which the processing is performed by use of transistor or tube juctions, rather than passive componenets such as resistors, capacitors, and coils. Such items as crossovers and equalizers may be constructed either way. Active processing usually affords more more options, and greater precision, albeit at greater cost.
Submitted on Wednesday, June 11, 2008 3:43:42 PM

14. Active:
The type of circuitry that requires a power supply and usually uses transistors, integrated circuits, and/or printed circuit boards. (e.g., By using an active crossover, it is much easier to achieve 18 dB/octave or 24 dB/octave slopes.)
Submitted on Saturday, September 30, 2006 3:43:42 PM

15. Active
Definition:The type of circuitry that requires a power supply and usually uses transistors, integrated circuits, and/or printed circuit boards. (e.g., By using an active crossover, it is much easier to achieve 18 dB/octave or 24 dB/octave slopes.)
Submitted on Thursday, March 12, 2009 3:43:42 PM

16. Active Display:-A special feature for front panel receiver displays that generates animated patterns for both segmented and dot matrix LCDs that proceed the sequential display of information such as clock, CD titles, and radio station call letters and frequencies.
Submitted on Monday, April 20, 2009 3:43:42 PM

17. Adaptive Reception-A circuit that provides adjustable delay such that the time at which a sound wave is produced from various signal channels can be changed. This allows synchronization for each channel of a multi-channel output device, so that sound waves from multiple speakers will converge at approximately the same time at a single point in space (the listener).
Submitted on Sunday, May 06, 2007 3:43:42 PM

18. AES/EBU
Balanced digital connection. For example, used to connect a CD transport to a DAC. The AES/EBU standard uses XLR type connectors.
Submitted on Friday, January 30, 2009 3:43:42 PM

19. AIFF:-Short for Audio Interchange File Format, a file format for storing and transmitting sampled sound. It was developed by Apple Computer and is the standard audio format for Macintosh computers. Files are 8-bit mono or stereo and generally end with a .AIF or .IEF extension. Normal AIFF does not support data compression so files tend to be large, but another format called AIIF-Compressed (AIFF-C or AIFC) does support compression.
Submitted on Friday, December 01, 2006 3:43:42 PM

20. Air Gap:In a speaker's motor section, the space between the top plate and the pole piece. This is where the magnetic flux field is concentrated and where the voice coil interacts with it.
Submitted on Wednesday, February 28, 2007 3:43:42 PM

21. Alignment:
A class of enclosure parameters that provides optimum performance for a woofer with a given value of Q.
Submitted on Thursday, October 19, 2006 3:43:42 PM

22. Alpha:-Term used in sealed enclosure designs to mean the ratio of Vas to Vb, where Vb is the volume of the box you will build.
Submitted on Wednesday, November 05, 2008 3:43:42 PM

23. Alternating Current
Electricity which flows in opposite directions, alternating at a certain rate (Hz). As supplied by power companies, AC in the United States alternates 60 times per second and is deemed as 60 Hz power. However; some countries have a 50 Hz system, and ships and aircraft may use 400 Hz.
Submitted on Friday, October 27, 2006 3:43:42 PM

24. Alternating Current (AC):An electrical current that periodically changes in magnitude and direction.
Submitted on Friday, December 07, 2007 3:43:42 PM

25. Alternator-The electricity producing device in a car that charges the battery, powers all the electrical accessories when the engine is running, and sometimes causes alternator whine in car audio systems. (e.g., High output alternators can cause even more noise to flow on the car's chassis.)
Submitted on Monday, June 09, 2008 3:43:42 PM

26. Alternator:
The electricity producing device in a car that charges the battery, powers all the electrical accessories when the engine is running, and sometimes causes alternator whine in car audio systems. (e.g., High output alternators can cause even more noise to flow on the car's chassis.)
Submitted on Tuesday, August 12, 2008 3:43:42 PM

27. Alternator Whine:
A siren-like whining that appears as the rotational speed of an engine increases. The noise is usually the result of a voltage differential created by more than one ground path or a poor ground path to the affected equipment.
Submitted on Friday, June 15, 2007 3:43:42 PM

28. Ambience:-The acoustic characteristics of a space with regard to reverberation. A room with a lot of reverb is said to be "live"; one without much reverb is "dead."
Submitted on Sunday, September 10, 2006 3:43:42 PM

29. Amp or Amperage-The amount of current flowing in a circuit. In a 12-volt world, we use lots of amps to operate our accessories. (e.g., When my system is really crankin' it draws 20 amps from my alternator.)
Submitted on Thursday, May 03, 2007 3:43:42 PM

30. Amp or Amperage:The amount of current flowing in a circuit. In a 12-volt world, we use lots of amps to operate our accessories. (e.g., When my system is really crankin' it draws 20 amps from my alternator.)
Submitted on Sunday, May 18, 2008 3:43:42 PM

31. Ampere (A)
Definition:The unit of measurement for electrical current in coulombs per second. There is one ampere in a circuit that has one ohm resistance when one volt is applied to the circuit. See Ohms Law.
Submitted on Friday, February 01, 2008 3:43:42 PM

32. Amperes (A):-Ampere is a unit measurement of current of electrical energy equal to one coulomb of charge per second. Most DC applications refer to positive current - current which flows from a positive potential to a more negative potential, with respect to a reference point which is designated as zero or neutral potential (usually ground). The electrons in a circuit flow in the opposite direction as the current itself. Ampere is commonly abbreviated as "amp", not to be confused with amplifiers, of course, which are also commonly abbreviated "amp". In computation, the abbreviation for amperes is commonly, "I".
Submitted on Tuesday, June 19, 2007 3:43:42 PM

33. Amplification Classes.-All sound is a sinosoidial waveform. It has alternating peaks and valleys. The center point of each wave is the zero, or switching point that separates the positive (top) from the negative (bottom) portion of each wave. When a tube or transistor amplifier operates in Class A, the output tubes or transistors amplify the entire waveform without splitting it into positive and negative halves. In Class AB, used in the overwhelming majority of amplifier designs, the signal is split into two halves, positive and negative, and each half is sent to a tube or transistor circuit for amplification. Both sides work in tandem, and the two halves are recombined at the output section to reconstruct the whole signal. This technique increases the amount of power that can be applied, but increases distortion. Class A amps usually provide lower, often imperceptable distortion, but at the expense of reduced power output.Class D or High Current operation is essentially rapid switching, hence the term switching power amplifier. Here the output devices are rapidly switched on and off at least twice for each cycle. Theoretically, since the output devices are either completely on or completely off they do not dissipate any power. If a device is on there is a large amount of current flowing through it, but all the voltage is across the load, so the power dissipated by the device is zero; and when the device is off, the voltage is large, but the current is zero. Consequently, class D operation (often, but not necessarrily digital) is theoretically 100% efficient, but this requires zero on-impedance switches with infinitely fast switching times -- a product yet to be made; meanwhile designs do exist with efficiencies approaching 90%. This is a design that is increasimgly popular for use in bass systems, where maximum power is necessary, and slightly elevated levels of distortion are easily tolerated.
Submitted on Monday, December 22, 2008 3:43:42 PM

34. Amplifier
A device, either a single stage or a large scale circuit with mutiple stages for creating gain, ie. making small signals larger.
Submitted on Saturday, February 23, 2008 3:43:42 PM

35. Amplifier (Amp)-A device which increases signal level. Many types of amplifiers are used in audio systems. Amplifiers typically increase voltage, current or both.
Submitted on Saturday, December 29, 2007 3:43:42 PM

36. Amplifier classes
Definition:Audio power amplifiers are classified primarily by the design of the output stage. Classification is based on the amount of time the output devices operate during each cycle of signal swing. Also defined in terms of output bias current, (the amount of current flowing in the output devices with no signal). Class A operation is where both devices conduct continuously for the entire cycle of signal swing, or the bias current flows in the output devices at all times. The key ingredient of class A operation is that both devices are always on. There is no condition where one or the other is turned off. Because of this, class A amplifiers are single-ended designs with only one type polarity output devices. Class A is the most inefficient of all power amplifier designs, averaging only around 20%. Because of this, class A amplifiers are large, heavy and run very hot. All this is due to the amplifier constantly operating at full power.The positive effect of all this is that class A designs are inherently the most linear, with the least amount of distortion. Class B operation is the opposite of class A. Both output devices are never allowed to be on at the same time, or the bias is set so that current flow in a specific output device is zero when not stimulated with an input signal, i.e., the current in a specific output flows for one half cycle. Thus each output device is on for exactly one half of a complete sinusoidal signal cycle. Due to this operation, class B designs show high efficiency but poor linearity around the crossover region. This is due to the time it takes to turn one device off and the other device on, which translates into extreme crossover distortion. Thus restricting class B designs to power consumption critical applications, e.g., battery operated equipment, such as 2-way radio and other communications audio. Class AB operation allows both devices to be on at the same time (like in class A), but just barely. The output bias is set so that current flows in a specific output device appreciably more than a half cycle but less than the entire cycle. That is, only a small amount of current is allowed to flow through both devices, unlike the complete load current of class A designs, but enough to keep each device operating so they respond instantly to input voltage demands. Thus the inherent non-linearity of class B designs is eliminated, without the gross inefficiencies of the class A design. It is this combination of good efficiency (around 50%) with excellent linearity that makes class AB the most popular audio amplifier design. Class AB plus B design involves two pairs of output devices
Submitted on Thursday, December 18, 2008 3:43:42 PM

37. Amplitude:The strength or intensity of an AC signal applied by the amplifiers output to a speaker's input. Also, a measure of the relative power of any variable recurring phenomenon. Typically, measurements are made in Decibels.
Submitted on Friday, November 16, 2007 3:43:42 PM

38. Amplitude:-The level or strength of a signal. (e.g., A high-powered amplifier will raise the amplitude of your deck's signal to over 50 volts.)
Submitted on Thursday, November 29, 2007 3:43:42 PM

39. Amplitude:-The level or strength of a signal. (e.g., A high-powered amplifier will raise the amplitude of your deck's signal to over 50 volts.)
Submitted on Saturday, August 16, 2008 3:43:42 PM

40. Amplitude Modulation (AM):In radio broadcasting, amethod of modulation in which the amplitude of the carrier voltage is varied in proportion to the changing frequency value of an applied (audio) voltage. (Also see Frequency Modulation).
Submitted on Saturday, December 30, 2006 3:43:42 PM

41. AMS:Automatic Music Search. A feature that allows a CD or cassette mechanism to skip forward or backwards to another track.
Submitted on Tuesday, July 03, 2007 3:43:42 PM

42. An Ohm:
is a measure of resistance and impedance that tells you how much a device (like a speaker) will resist the flow of current in a circuit. If the same exact signal is sent into two speakers, one rated at 4 ohms of impedance, the other at 8 ohms of impedance, twice as much current will flow through the 4 ohm speaker as the 8 ohm speaker. All things being equal, the 8 ohm speaker requires twice as much power to achieve the same volume level, since power is proportional to current. (See "dB.") Can your impedance be too low? Yes it can. It all depends on how well your amplifier can handle the increase in current flow that comes with lower impedance. The more current, the hotter your amp will get. An overheating amp is trouble. A good amp will simply shut down when trying to generate too much current. A poor quality amp will burn. Makes sure your amp can handle the impedance of your speakers.
Submitted on Wednesday, September 05, 2007 3:43:42 PM

43. Analog:
The signal whose instantaneous value is a replication of another event or signal. (e.g., The digital bits on a compact disc are converted to an analog signal inside the D/A converter of the deck so that our brains can understand the software.)
Submitted on Saturday, April 04, 2009 3:43:42 PM

44. Analog-The signal whose instantaneous value is a replication of another event or signal. (e.g., The digital bits on a compact disc are converted to an analog signal inside the D/A converter of the deck so that our brains can understand the software.)
Submitted on Monday, June 30, 2008 3:43:42 PM

45. Analog
Before digital, the way all sound was reproduced.
Submitted on Friday, February 20, 2009 3:43:42 PM

46. Analog:An electrical signal in which the frequency and level vary continuously in direct relationship to the original acoustical sound waves. Analog may also refer to a control or circuit which continuously changes the level of a signal in a direct relationship to the control setting.
Submitted on Monday, June 11, 2007 3:43:42 PM

47. Analog Switch
Definition:A hardware-oriented switch that only passes signals that are faithful analogs of transducer parameters.
Submitted on Saturday, February 24, 2007 3:43:42 PM

48. Anechoic chamber:-A special room that is constructed without acoustically reflective surfaces, such that it is without echoes, or an-echo-ic. This experimental setup enables engineers to more precisely measure the acoustical properties of many types of equipment. A real life anechoic situation is experienced by skydivers. However, they may be a bit distracted from the experience by the approaching ground.
Submitted on Wednesday, April 08, 2009 3:43:42 PM

49. Angled (box or enclosure):A type of speaker enclosure wherein the woofers, or Drivers, are situated in a box that is angled on one side. This is usually done to facilitate a more direct coupling of the upper part of the speaker's range to the listening environment.
Submitted on Tuesday, January 15, 2008 3:43:42 PM

50. Anode
The electrically positive pole of an electronic device such as a semiconductor. A diode, for instance, has a positive and a negative pole; these are known as the anode and the cathode.
Submitted on Sunday, March 18, 2007 3:43:42 PM

51. Antenna-The rod that is used to receive radio waves in a car. (e.g., My radio can't pick up too much without the antenna all the way up.)
Submitted on Sunday, January 21, 2007 3:43:42 PM

52. Antenna
Definition:A device, such as a rod or wire, which picks up a received radio frequency signal or radiates a transmitted RF signal.
Submitted on Friday, January 11, 2008 3:43:42 PM

53. Antenna:The rod that is used to receive radio waves in a car. (e.g., My radio can't pick up too much without the antenna all the way up.)
Submitted on Tuesday, October 10, 2006 3:43:42 PM

54. Aperiodic:-Refers to a type of bass-cabinet loading. An aperiodic enclosure type usually features a very restrictive, (damped), port. The purpose of this restrictive port is not to extend bass response, but to yeild a smoother response pattern by lowering the Q of the system and reducing the impedance peak at resonance. Most restrictive ports are damped with quantities of sound absorbtive material.
Submitted on Tuesday, October 24, 2006 3:43:42 PM

55. Aperiodic
Definition:Refers to a type of bass-cabinet loading. An aperiodic enclosure type usually features a very restrictive, (damped), port. The purpose of this restrictive port is not to extend bass response, but lower the Q of the system and reduce the impedance peak at resonance. Most restrictive ports are heavily stuffed with fiberglass, dacron or foam.
Submitted on Wednesday, July 11, 2007 3:43:42 PM

56. ATA
Automatic Tuner Activation. A feature that allows the tuner to be accessed while a tape deck is rewinding or fast forwarding.
Submitted on Thursday, August 21, 2008 3:43:42 PM

57. ATRAC
Adaptive Transformation Acoustic Coding. The process used in MiniDisc that utilizes psychoacoustic principles to limit quantization noise and reduce the data quantity from 16 bits to 4 bits by using non-uniform frequency and time division.
Submitted on Saturday, February 21, 2009 3:43:42 PM

58. Attenuate:
To reduce in level.
Submitted on Sunday, July 30, 2006 3:43:42 PM

59. Attenuate:The act of reducing the Amplitude or intensity of a signal. In speaker systems, high frequency drivers are commonly more efficient than low frequency drivers. This creates a need to adjust the driver levels to create a uniform overall frequency response. L-pads are commonly used for many passive systems
Submitted on Wednesday, February 27, 2008 3:43:42 PM

60. Attenuate-A reduction in the level of a signal. (e.g., I had to attenuate the signal level from my deck so that I wouldn't clip the input to my amp so much.)
Submitted on Friday, May 25, 2007 3:43:42 PM

61. Attenuate
A reduction in the level of a signal. (e.g., I had to attenuate the signal level from my deck so that I wouldn't clip the input to my amp so much.)
Submitted on Wednesday, January 16, 2008 3:43:42 PM

62. Audio
1. Of, or relating to, humanly audible sound, i.e., audio is all the sounds that humans hear. 2. a. Relating to the broadcasting or reception of sound. b. Relating to high-fidelity sound reproduction.
Submitted on Saturday, January 31, 2009 3:43:42 PM

63. Audio Frequency Spectrum:-The band of frequencies extending roughly from 20 Hz to 20 kHz and encompassing the full range of normal human hearing.
Submitted on Thursday, October 16, 2008 3:43:42 PM

64. Audiophile:
A species of dedicated audio nut who actually reads definitions like this.
Submitted on Monday, March 03, 2008 3:43:42 PM

65. Audiophile:A person interested in sound reproduction.
Submitted on Saturday, December 09, 2006 3:43:42 PM

66. Auto Memory:-A tuner feature that automatically finds the strongest stations in the local area, and places them in preset memories
Submitted on Thursday, November 06, 2008 3:43:42 PM

67. Auto reverse
In a cassette player, the feature in which the direction of tape travel changes automatically. (e.g., Since my deck is equipped with an auto-reverse mechanism, I don't need to turn the tape over when one side has finished playing.)
Submitted on Thursday, September 11, 2008 3:43:42 PM

68. Auto reverse
Definition:In a cassette player, the feature in which the direction of tape travel changes automatically. (e.g., Since my deck is equipped with an auto-reverse mechanism, I don't need to turn the tape over when one side has finished playing.)
Submitted on Tuesday, December 05, 2006 3:43:42 PM

69. Average or apparent power
The result of multiplying the rms value of the voltage by the rms value of the current in an electronic circuit. It is expressed in watts (W) for resistive loads and in voltamperes (VA) for reactive loads. The real power is usually less because of losses when the power factor is accounted.
Submitted on Wednesday, July 30, 2008 3:43:42 PM

70. AWG:
Acronym for American Wire Gauge, a standard for measuring the diameter of wire commonly used in electrical circuits. The higher the AWG number, the smaller the thickness of the conductor. For power carrying, choose lower numbers; for signal only wires, choose a higher number.
Submitted on Wednesday, September 19, 2007 3:43:42 PM

71. AWS
Definition:Adaptive Woofer System, trademark of ACI. An active woofer system with built in user adjustable equalization capabilities.
Submitted on Friday, February 27, 2009 3:43:42 PM

72. Azimuth
The relationship of a tape head gap to the magnetic lines of flux on a recorded tape. (e.g., If the azimuth is out of alignment, the high-frequency response will be poor.)
Submitted on Friday, July 13, 2007 3:43:42 PM

73. Azimuth
The relationship of a tape head gap to the magnetic lines of flux on a recorded tape. (e.g., If the azimuth is out of alignment, the high-frequency response will be poor.)
Submitted on Monday, April 23, 2007 3:43:42 PM

Go Top | Glossary