GROOVE Electronics

Understanding Audio Acronyms

posted on 5:41pm by Somebody

"A" is for amperes, which is a measurement of current equal to one coulomb of charge per second.

"AC" is for alternating current, which is a type of circuit in which the voltage potential fluctuates so that current can flow in either direction through the circuit.

"DC" is for direct current, which is a type of circuit in which current flows one way.

"dB" is for decibel, and is a measurement for power ratios.

"Frequency Response"of a device is the range of frequencies over which that device can perform.

"Hz" is for hertz, a measurement of frequency.

"MOSFET" is common type of transistor.

"Ohm" is a measurement of resistance and impedance, which tells you how much a particular device will resist the flow of current in a circuit.

"RMS" is a measurement associated with power.

"THD" is for total harmonic distortion, which is a measurement of the how much a device may distort a signal.

"V" is for volts, which is a measurement of electric potential.

"W" is for watts, a measurement of electrical power.

Comments (8)

What is a DVD?

posted on 5:52pm by David

DVD (also known as "Digital Versatile Disc" or "Digital Video Disc") is an optical disc storage media format that can be used for data storage, including movies with high video and sound quality. DVDs resemble Compact Discs because their diameter is the same (120 mm or 4.72 inches, or occasionally 80 mm or 3.15 inches), but they are encoded in a different format and at a much higher density.

All read-only DVD discs, regardless of type, are DVD-ROM discs. This includes replicated (factory pressed), recorded (burned), video, audio, and data DVDs. A DVD with properly formatted and structured video content is a DVD-Video disc. DVDs with properly formatted and structured audio are DVD-Audio discs. Everything else (including other types of DVD discs with video) is referred to as a DVD-Data disc. Many people use the term "DVD-ROM" to refer to pressed data discs only, but that is not technically correct.

The term DVD is also being applied as a generic term to describe newer video formats, both Blu-ray Disc and HD DVD.

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What is a speaker?

posted on 5:49pm by David

A loudspeaker, speaker, or speaker system is an electromechanical device which converts an electrical signal into sound. The term loudspeaker is used for both individual devices and for complete systems consisting of one or more drivers (as the individual transducers are often called) in an enclosure, often with a crossover circuit.

Loudspeakers are used in numerous applications from hearing aids to air raid sirens. Their cost may range from pennies in a cheap radio to high-fidelity speaker systems costing millions of dollars. Loudspeakers are the most variable elements in any audio system, no matter the cost, and may be responsible for marked audible differences between otherwise identical systems.

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What is a CD (compact disc)?

posted on 5:52pm by David

A Compact Disc or CD is an optical disc used to store digital data, originally developed for storing digital audio. The CD, available on the market in late 1982, remains the standard physical medium for commercial audio recordings as of 2007. An audio CD consists of one or more stereo tracks stored using 16-bit PCM coding at a sampling rate of 44.1 kHz. Standard CDs have a diameter of 120 mm and can hold approximately 80 minutes of audio. There are also 80 mm discs, sometimes used for CD singles, which hold approximately 20 minutes of audio. Compact Disc technology was later adapted for use as a data storage device, known as a CD-ROM, and to include record-once and re-writable media (CD-R and CD-RW respectively). CD-ROMs and CD-Rs remain widely used technologies in the PC industry as of 2007. The CD and its extensions have been extremely successful: in 2004, the annual worldwide sales of CD-Audio, CD-ROM, and CD-R reached about 30 billion discs.

In 1979 Philips and Sony set up a joint task force of engineers to design the new digital audio disc. Prominent members of the task force were Kees Immink and Toshitada Doi. After a year of experimentation and discussion, the taskforce produced the "Red Book", the Compact Disc standard. Philips contributed the general manufacturing process, based on video LaserDisc technology. Philips also contributed the Eight-to-Fourteen Modulation (EFM), which offers both a long playing time and a high resilience against disc handling damage such as scratches and fingerprints, while Sony contributed the error-correction method, CIRC. The Compact Disc Story[1], told by a former member of the taskforce, gives background information on the many technical decisions made, including the choice of the sampling frequency, playing time, and disc diameter. According to Philips, the Compact Disc was thus "invented collectively by a large group of people working as a team[2]."

The Compact Disc reached the market in late 1982 in Asia, and early the following year in the United States and other markets. The first CDs available were 16 Japanese-made titles from CBS/Sony. This event is often seen as the "Big Bang" of the digital audio revolution. The new audio disc was enthusiastically received, especially in the early-adopting classical music and audiophile communities and its handling quality received particular praise. As the price of players sank rapidly, the CD began to gain popularity in the larger popular and rock music markets.

The CD was originally thought of as an evolution of the gramophone record, rather than primarily as a data storage medium. Only later did the concept of an 'audio file' arise, and the generalising of this to any data file. From its origins as a music format, Compact Disc has grown to encompass other applications. In June 1985, the CD-ROM (read-only memory) and, in 1990, CD-Recordable were introduced, also developed by Sony and Philips.

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