B+ Vacuum Tubes. The symbol for the high voltage power supply found in battery-operated radios featuring vacuum tubes. In these designs there was an "A" supply for the filaments, a "B" supply for high voltage, a "C" supply for bias and a "D" supply for screen grids. [Pittman]
babbling tributary In LAN technology, a workstation that constantly sends meaningless messages.
babel Loud, confused, or disagreeable sound that stresses confusion of vocal sounds arising from simultaneous utterance and random mixture of languages. After Babel, the biblical city (now thought to be Babylon) in Shinar where God confounded a presumptuous attempt to build a tower into heaven by confusing the language of its builders into many mutually incomprehensible languages. [AHD]
back-EMF (back-electromotive force) See also EMF. Literally, back-voltage, is a phenomena found in all moving-coil electromagnetic systems, but for audio is most often used with respect to loudspeaker operation. This term describes the action where, after the signal stops, the speaker cone continues moving, causing the voice coil to move through the magnetic field (now acting like a microphone), creating a new voltage that tries to drive the cable back to the power amplifier's output. If the loudspeaker is allowed to do this, the cone flops around like a dying fish. It does not sound good. The only way to stop back-emf is to make the loudspeaker "see" a dead short, i.e., zero ohms looking backward, or as close to it as possible. See damping factor.
background music Abbr. BGM Officially music without lyrics and not performed by the original artist, used as an alternative to silence. Contrast with foreground music.
background noise Acoustics. The total noise from all sources other than a particular sound that is of interest (e.g., other than the sound being measured or other than the speech or music being listened to). [Harris]
backward masking See temporal masking.
baffle Loudspeakers. In its simplest form, the main speaker mounting board in a cabinet, whose primary purpose is to separate the front and rear sound waves, from here it becomes a very complex subject.
baglama Musical Instrument. A Turkish stringed instrument most commonly used for folk music,, sometimes called saz.
bagpipe Musical Instrument. A musical instrument having a flexible bag inflated either by a tube with valves or by bellows, a double-reed melody pipe, and from one to four drone pipes. [AHD]
Baker clamp Electronics. A circuit technique dating from the early '50s using a diode as a clamp to prevent deep transistor saturation by providing a path for excessive base drive current. Recently used by National Semiconductor in a popular audio power amplifier IC to aid in fast recovery from peak overloads. Hit the link for details.
Bakersfield sound Music. A style made popular by Bakersfield, CA hometown boys, Merle Haggard and Buck Owens, featuring heavy twangy steel guitar.
baking Sound Recording. The name for the process required for old analog tapes where they must be put into an oven and "baked" to remove moisture and prevent the oxide from shedding onto the tape heads.
balance control A control found most commonly on professional and consumer stereo preamplifiers, used to change the relative loudness (power) between the left and right channels. Attenuating the opposite channel makes one channel (apparently) louder. This is most often done (in analog designs) with a dual potentiometer with an "M-N taper." An M-N taper consists of a "shorted" output for the first 50% of travel and then a linear taper for the last 50% of travel, operating oppositely for each channel. Therefore, with the control in its center detent position, there is no attenuation of either channel. Rotating it away from the center position causes one channel to be attenuated, while having no effect on the other channel, and vice-versa. Contrast with pan and crossfade controls.
balanced line The IEC standard on amplifiers explains a balanced interface by saying that "The purpose of a balanced interface is to transfer a desired signal as a differential voltage on two signal lines." (IEC 60268-3:2001, page 111). It goes on to explain "... only the common-mode impedance balance of the driver, line, and receiver play a role in noise or interference rejection. This noise or interference rejection property is independent of the presence of a desired differential signal. Therefore, it can make no difference whether the desired signal exists entirely on one line, as a greater voltage on one line than the other, or as equal voltage on both of them."
Balanced lines are the preferred method (for hum free) interconnecting of sound systems using a shielded twisted-pair. Because of its superior noise immunity, balanced lines also find use in interconnecting data signals, e.g., RS-422, and digital audio, e.g., AES/EBU. The principal behind balanced lines is that the signal is transmitted over one wire and received back on another wire. The shield does not carry any information, thus it is free to function as a true shield, but must be earth grounded at each end to be successful. (For a detailed tutorial on proper grounding practices, see RaneNote Sound System Interconnection) This circuit's shining virtue is its great common-mode noise rejection ability. The concept here relies on induced noise showing up equally (or common) on each wire. It is mainly due to EMI (electromagnetic interference: passing through or near magnetic fields), RFI (radio frequency interference: strong broadcast signals), noisy ground references, or a combination of all three. A true balanced line exhibits exactly equal impedance from each line relative to ground, guaranteeing equal noise susceptibility. Since the balanced input stage amplifies only the difference between the lines, it rejects everything else (noise) that is common to the lines.
Ball, Roland Sherwood "Ernie"(1930-2004) American musician/entrepreneur who developed guitar strings and accessories into an art form.
ballistics See meter ballistics.
balun (balanced-unbalanced) A jargon term originally popularized by radio engineers referring to the balanced to unbalanced transformer used to interface with the radio antenna. Today, expanded to refer to any interface (usually a transformer) between balanced and unbalanced lines or circuitry; may also provide impedance transformation, as 300 ohm balanced to 75 ohm unbalanced, or vice versa. Another popular use is in transitioning between balanced twisted-pair and an unbalanced coaxial cable.
banana jack or banana plug See connectors.
banda Music. A popular brass, woodwind and percussion music style that began in Mexico and spread from there.
bandpass filter A filter that has a finite passband, neither of the cutoff frequencies being zero or infinite. The bandpass frequencies are normally associated with frequencies that define the half power points, i.e. the -3 dB points. See Figure 1 of the RaneNote Constant-Q Graphic Equalizers.
bandwidth Abbr. BW 1. Electronic filters The numerical difference between the upper and lower -3 dB points of a band of audio frequencies. Used to figure the Q, or quality factor, for a filter. See Figure 1 of RaneNote Constant-Q Graphic Equalizers; also download "Bandwidth vs. Q Calculator" as a zipped Microsoft Excel spreadsheet in the Rane Library. 2. Telecommunications The size of the communications channel. In analog communications, bandwidth is measured in Hertz (Hz), while digital communications measures bandwidth (data transfer rate) in bits per second. For example, an analog telephone channel has a bandwidth of 4,000 Hz, while a digitally coded telephone channel has a bandwidth of 64 kilobits/second. See the RaneNote Audio Specifications.
banhu Musical Instrument. Chinese bowed 2-string fiddle.
banjo "I can see fiddling around with a banjo, but how do you banjo around with a fiddle?" -- Duncan Purney [from Barber]
banjo Musical Instrument. An instrument with strings stretched across a membrane over a resonant cavity.
banjolin Musical Instrument. An instrument combining a banjo and a mandolin.
Banjo Paterson See: Paterson, A.B.
bantam jacks See: TT.
Bara, Theda (1890-1955) Anagram of "Arab Death," used as a pseudonym by the Cincinnati-born, Hollywood actress Theodosia Goodman in the 1920s, who became the first woman movie star.
barberpole tone (or effect) See Shepard function generator.
barber's music Used to describe non-professional music named after the fact that barber's shops used to have a guitar or other acoustic instrument on hand for customer's use while waiting. [Kacirk]
Barkhausen noise Loudspeakers. A coil of wire wound on the ferromagnetic material can demonstrate the sudden, discontinuous jumps in magnetization. The sudden transitions in the magnetization of the material produce current pulses in the coil. These can be amplified to produce a series of clicks in a loudspeaker. This sounds as crackle, complete with skewed pulses which sounds like candy being unwrapped, Rice Krispies, or a pine log fire. [from Wikipedia entry] Transformers. Noise associated with the deformation of magnetic domains in the core of a transformer. [IEEE]
Baroque 1. Music: of, relating to, or characteristic of a style of composition that flourished in Europe from about 1600 to 1750, marked by chromaticism, strict forms, and elaborate ornamentation. [AHD] 2. When you are out of Monet. (Thanks JF and I'll never tell.)
barrelhouse Style of boogie piano playing. [Decharne]
barrier strips Same as terminal strips, see connectors.
Barron, Louis & Bebe (Louis: 1920-1989; Bebe:1925-2008) American husband and wife team that composed the first electronic-music score featured in the movie, Forbidden Planet, in 1956.
baseband A transmission medium with capacity for one channel only. Typically found in local area networks (LANs). In baseband LANs, the entire bandwidth, or capacity, of the cable is used to transmit a single digital signal. Everything on that cable (transmitted or received) must use that one channel, which is very fast, so each device needs only to use that high speed channel for only a little of the time. Therefore all attached devices (printers, computers, databases) share by taking turns using the same cable. Baseband as used in videoconferencing means audio and video signals are transmitted over separate cables. Contrast with broadband
baseband signaling Transmission of a digital or analog signal at its original frequencies; i.e., a signal in its original form, not changed by modulation.
BASH® (Bridged Amplifier Switching Hybrid) Audio Amplifiers. The registered trademark of Indigo, an OEM company, for their patented (U.S. 5,075,634 & U.S. 5,510,753) Class H power amplifier technology that uses a fast-response, pulse-width modulated power supply and a linear Class AB amplifier. BASH modules are found in many powered loudspeakers.
Basilica Soundscape Festival The ultimate eclectic alternative music festival, held annually in an old train-wheel factory in Hudson, NY.
Bass Coast Festival A Canadian eclectic music and arts festival held in Merritt, British Columbia (about 167 mi, or 269 km, northeast of Vancouver, unique for having no corporate sponsorship.
bass management Home Cinema. A circuit that sums all the frequencies below 80Hz from the main channels and the signal from the LFE channel and delivers it (normally) to the subwoofer. Compare with LFE.
bass ratio (BR) Acoustics. An objective measure of sound "warmth."
bass reflex Loudspeakers. Invented by Thuras in 1930, a type of cabinet design featuring a "port" (a vent or opening of any shape) on the baffle to allow the rear sound wave to exit (in phase -- that is the trick) with the front wave. Originally a trademark of the Jensen Company in the 1930s. [White], this popular design is also called a vented loudspeaker.
Batá drum Musical Instrument. A set of three double-headed hourglass-shaped drums originating in Africa.
battery Electronics. Invented and named by Benjamin Franklin in the 1748. He named his device for storing electrical charge for their resemblance to rows of guns.
battle axe Musician slang for a trumpet. [Decharne]
baud rate (pronounced "bawd"; after Baudot Code named for the French telegrapher Emile Baudot, 1845-1903) The transmitted signaling speed, or keying rate of a modem. Often confused with bit rate. Bit rate and baud rate are NOT synonymous and shall not be interchanged in usage. For example, one baud equals one half dot cycle per second in Morse code, one bit per second in a train of binary signals, and one 3-bit value per second in a train of signals each of which can assume one of 8 different states, and so on - all brought to you by the magic of advanced coding techniques that allow more than one bit per baud. Preferred usage is bit rate, with baud used only when the details of a modem are specified.
Bauer, Benjamin (1913-1979) Russian-American engineer who made powerful contributions to the development of many electroacoustic devices including microphones (see: Unidyne), phonograph pickups and tape recording heads. He worked for Shure from 1936 (as a co-op student) to 1957 (leaving as vice president), then CBS Laboratories as vice president.
Baxandall tone controls The most common form of active bass and treble tone control circuit based upon British engineer P.J. Baxandall's paper "Negative Feedback Tone Control -- Independent Variation of Bass and Treble Without Switches," Wireless World, vol. 58, no. 10, October 1952, p. 402. The Baxandall design is distinguished by having very low harmonic distortion due to the use of negative feedback.
Bayou Country Superfest The title says it all; held annually in Baton Rouge since 2010.
bazouki See bouzouki.
BCC (binaural cue coding) Audio Compression. An audio coding technology.
BCD 1. (binary-coded decimal) Pertains to a number system where each decimal digit is separately represented by a 4-bit binary code; for example, the decimal number 23 is represented as 0010 0011 (2 = 0010 and 3 = 0011, grouped together as shown), while in straight binary notation, 23 is represented as 10111. 2. (binary-coded digit) A digit of any number system that is represented as a fixed number of binary digits; from the previous example, the decimal digit 23 is represented as 10111.
beamforming Acoustics. A technique utilizing special microphone arrays combined with signal processing to determine where sound originates. Teleconferencing. For instance, see Rambo U.S. Patent 7,190,775 High quality audio conferencing with adaptive beamforming.
beam steering Loudspeakers. Common name for the technology that allows changing the directionality of a loudspeaker array by using separate DSP and power amplifiers for each driver in the array. This allows each driver to be delayed and equalized separately as necessary to manipulate the vertical coverage pattern. The whole beam can be moved upward, downward, and made broader or narrower as desired. Very clever; very expensive.
beat Physics. To cause a reference wave to combine with a second wave so that the frequency of the second wave can be studied through time variations in the amplitude of the combination. [AHD]
beats Music. Periodic fluctuations that are heard when sounds of slightly different frequencies are superimposed. [Everest]
beat frequency Equal to the absolute value of the difference in frequency of two waves beating together (see "beat" above).
In The Origins of the Beat Generation Jack Kerouac (1922-1969) recalled how he borrowed the term that labeled an entire decade from a broken-down drug addict named Herbert Huncke and how he then went on to use it himself. "John Clellon Holmes ... and I were sitting around trying to think up the meaning of the Lost Generation and the subsequent existentialism and I said, 'You know, this is really a beat generation': and he leapt up and said, 'that's it, that's right.'" [Bartlett's Book of Anecdotes] Holmes went on to publish "This is the Beat Generation" in The New York Times Magazine in 1952; the first published use of the term. Also see Generation X.
beat matching or beat mixing Used by disc jockeys to match beats to produce a seamless segue, or transition, between songs, or by turntablists between segments of different songs being mixed together. See Disc Jockey 101 for mixing, and Beat Matching Tips for matching.
beatnik Term created by famed San Francisco Chronicle columnist Herb Caen in 1958. He explained: "the word just popped out."
bebop Modern jazz style developed by Charlie Parker, Dizzy Gillespie and others in the early 1940s. Dizzy put out a single called "Bebop" in 1945 and also released "He Beeped When He Shoulda Bopped," in 1946. [Decharne] See bop.
Begun, Semi Joseph (1905-1995) Born in German, he immigrated to the U.S. in 1935 and pioneered magnetic tape recording. He wrote the first book published on magnetic recording and invented many recording products including the first consumer tape recorder as well as developing the technology that gave birth to the Black Box flight data recorder. Subject of a fascinating book by Mark Clark.
Belchfire® Series Term coined by Crown International for their mythical power amplifier, the BF-6000SUX. Based on original research into the first principles of teramagnostriction quasar-quadrature, the BF-6000SUX could have changed the design of all future power amps, but it didn't. In spite of Crown's leap forward into the past of technical declination, the marketplace categorically stated that it did not want 6,000 watts per channel in only one rack space - in spite of its six-foot depth and 206 pounds weight. The only known use of a BF-6000SUX was to drive the experimental Electro-Voice Rearaxial Softspeaker, when Rane demoed their PI 14 Pseudoacoustic Infector using Jensen's JE-EP-ERs Multi-denomial Transpedance Informer for coupling -- but many consider that only hearsay.
Bell, Alexander Graham (1847-1922) Scottish-born American inventor of the telephone. The first demonstration of electrical transmission of speech by his apparatus took place in 1876. Bell also invented the audiometer, an early hearing aid, and improved the phonograph. [AHD]
bellest bottoms A term coined by Steve King, editor and publisher of Today in Literature, in a note about Robert Heinlein that appeared in the July 7, 2010 issue. He says it is "intended to suggest biggest/best bell-bottom jeans."
Bell's Law of Telephony "No matter what technology is used, your monthly phone bill magically remains about the same size." [A Dictionary of the Near Future by Douglas Coupland, NY Times, September 12, 2010.]
belly fiddle Guitar. [Decharne]
BEM (boundary element modeling) Acoustics. A mathematical modeling method using only a mesh of the surface of a wave, making computations easier and faster.
benders or bending See circuit-bending.
bending wave physics (also known as Distributed Mode Loudspeakers or DML) Loudspeakers. The latest trend in flat panel loudspeaker innovations based on the bending wave principal. Its simplest form consists of a small driver and a large thin panel. The driver coil excites the panel but due to the large flat surface, it does not move in and out but rather "bends"- that is, deforms in a bending wave. This wave travels throughout the panel provoking 360-degree radiation of sound in the process -- very different from the way a conventional loudspeaker cone produces sound by "pushing" air. Careful and complex design of the rigidity of the thin flexible panel allows it to increase from the middle to the edges at an equal ratio. This allows one panel to control most of the audio range, thus eliminating multiple drivers and crossover networks. See Colloms for theory. Also see Peter Dick's bending wave converter.
Benten or Ben Zai Ten Japanese Deity. Goddess of music. The name of one of the Seven Gods of Good Fortune, the goddess of music, art, happiness and love.
BER (bit error ratio) (also called bit error rate) 1. The ratio of the number of erroneous bits divided by the total number of bits transmitted, received, or processed over some stipulated period. 2. The number of bits processed before an erroneous bit is found (e.g., 10E13), or the frequency of erroneous bits (e.g., 10E-13).
Berliner, Emil (1851-1929) German-born American inventor who made important contributions to telephone technology and developed the phonograph record disc.
Berserktown A music festival focused on lesser known bands, started in 2014 in Los Angeles.
Bessel crossover A type of crossover utilizing low-pass filter design characterized by having a linear phase response (or maximally flat phase response), but also a monotonically decreasing passband amplitude response (which means it starts rolling off at DC and continues throughout the passband). Linear phase response (e.g., a linear plot of phase shift vs. frequency produces a straight line) results in constant time-delay (all frequencies within the passband are delayed the same amount). Consequently the value of linear phase is it reproduces a near-perfect step response, i.e., there is no overshoot or ringing resulting from a sudden transition between signal levels. The drawback is a sluggish roll-off rate. For example, for the same circuit complexity a Butterworth response rolls off nearly three times as fast. This circuit is based upon Bessel polynomials; however, the filters whose network functions use these polynomials are correctly called Thompson filters [W.E. Thomson, "Delay Networks Having Maximally Flat Frequency Characteristics," Proc. IEEE, part 3, vol. 96. Nov 1949, pp. 487-490]. The fact that we do not refer to these as Thompson crossovers demonstrates, once again, that we do not live in a fair world. See Ray Miller's Bessel Filter Crossover and Its Relation to Other Types.
B-field See magnetic flux density.
B-format See: soundfield microphone.
BGA (ball grid array) Electronics. A type of miniature package for integrated circuits containing hundreds of pins.
BGM See: background music
biamp, biamplified, or biamplification Term used to refer to a 2-way active crossover where the audio signal is split into two paths, and using separate power amplifier channels for each driver.
bias or biasing Electronics. Preset voltages or currents in an electronic circuit that determine the electrical operating points of certain devices.
BICSI® (Building Industry Consulting Services, International) A telecommunications association that is a worldwide resource for technical publications, training, conferences, and registration programs for low-voltage cabling distribution design and installation.
bidirectional microphone See: microphone polar response.
bilabial Phonology. Pronounced or articulated with both lips, as the consonants b, p, m, and w. [AHD]
BIEM (Bureau International des Sociétés Gérant les Droits d'Enregistrement et de Reproduction Mécanique) An international organization representing mechanical rights societies found in most countries. They license the reproduction of songs (including musical, literary and dramatic works). Their members are composers, authors and publishers and their clients are record companies and other users of recorded music. They also license the downloading of music via the Internet.
bifilar windings A term most often associated (in the pro audio industry) with audio transformer design describing the winding technique of laying two wires side-by-side, providing essentially unity coupling, thus reducing leakage inductance to negligible amounts. Literally two threads from Latin bi- two, and filum thread.
Big Ear Festival A popular mixed-genre small music festival held in Knoxville, TN.
Big Guava Music festival held in Tampa Bay, FL featuring carnival rides as well as music on four stages, and lots of food trucks.
bigit Very early contraction term for "binary digit," now obsolete. (Mentioned by Edmund C. Berkeley in his book The Computer Revolution, Doubleday, 1962, page 234.) See bit.
bilinear transform A mathematical method used in the transformation of a continuous time (analog) function into an equivalent discrete time (digital) function. Fundamentally important for the design of digital filters. A bilinear transform ensures that a stable analog filter results in a stable digital filter, and it exactly preserves the frequency-domain characteristics, albeit with frequency compression.
BIM (building information modeling) A term coined by Georgia Institute of Technology for a very complex method of using digital models for design and construction of buildings. It is finding use in pro audio acoustic modeling tools.
bimorph Piezoelectric Microphones. A cantilever device having two active piezoelectric layers where an electrical field causes one layer to bend out and the other layer to bend in. Compare with: unimorph.
binary A condition in which there are two possible states; for example, the binary number system (base-2) using the digits 0 and 1. See the RaneNote Digital Dharma of Audio A/D Converters. For a delightful treat see: Binary Hand Dance by Vi Hart.
binary logarithm A logarithm based on the powers of 2 (aka base 2).
binaural cue coding See BCC.
binaural recording or binaural sound Believe it or not, the groundwork was laid in the 1920s (no kidding, and some claim even earlier) when the idea of placing two microphones in a dummy head was first introduced as a source of loudspeaker stereo (which wouldn't go anywhere until Blumlein's contributions). It was the Germans who first produced a standard artificial listener for evaluating auditorium acoustics, and then played back the results over headphones -- the startling realism launched binaural recording. A binaural recording is made using two microphones placed in the ear canals of an anatomically accurate dummy head, such that all the normal spatial attributes of the human head are present (just as in real listening situations) when the recording is made. Designed to be played back through headphones, the results are nothing but astonishing. First time listeners to binaural recordings often swear someone is there with them, talking and walking around them, such is the realism accomplished.
binding post See connectors.
binky See Larry Blake's Film Sound Glossary.
biphase mark code (BMC) See: differential Manchester encoding.
bi-phase modulation See: BPSK.
bipolar transistor Pertaining to a semiconductor technology in which transistors are built from alternating layers of positively and negatively doped semiconductors material. [IEEE]
birefringence Physics. The resolution or splitting of a light wave into two unequally reflected or transmitted waves by an optically anisotropic medium such as calcite or quartz. Also called double refraction. [AHD]
bit Abbr. b Abbreviation for binary unit or binary digit. 1. The smallest amount of digital information. A bit can store or represent only two states, 0 and 1. [The original term binary unit was coined by John Tukey of Bell Laboratories to represent the basic unit of information as defined by Shannon as a message representing one of two states.] 2. A little bit -- from Old English bita, meaning a piece bitten off.
bit clock The synchronizing signal that indicates the rate of individual data bits over a digital audio interface.
bit error rate or bit error ratio See BER.
bit rate The rate or frequency at which bits appear in a bit stream. Applied to digital audio, bit rate (kbits/sec/channel) equals the sampling rate (kHz) times the number of bits per sample. The data bit rate for a CD, for example, is 1.41M bits per second (44.1 kHz x 16 bits per sample x 2 channels). [The oft-quoted CD bit rate of 4.3218 MHz is for the raw bit rate which comes from multiplying 7,350 frames per second by 588, the number of channel bits.]
bits -- data converter See data converter bits.
bit stream A binary signal without regard to grouping.
bit-mapped display A display in which each pixel's color and intensity data are stored in a separate memory location.
bi-wire Loudspeakers. A technique that uses two wires to connect between one power amplifier and one loudspeaker instead of the more conventional one-wire approach. Some high-end consumer loudspeakers provide two sets of terminals with a shorting bar that can be removed to allow bi-wiring. It is important to understand that this is NOT a biamped technique where an electronic crossover and two power amplifiers are used to drive the woofer and high-frequency drivers separately. Instead this is a typical loudspeaker with a built-in passive crossover network that separates the audio signal after it enters the cabinet into (at least) low and high frequency components driving the woofer and high-frequency driver(s). [A very popular technique among wire and cable manufacturers.]
Black, Harold S. (1898-1983) American electrical engineer and innovator most noted for his invention of negative feedback (U.S. patent 2,102,671).
black noise See noise color.
black stick Clarinet. [Decharne]
blame shifter Shifts the pitch of mistakes down one octave so the audience thinks it was the bass player. [Thanks to DD at Sound Path Labs.]
blooming Measurement. An increase in the blip size on the display as a result of an increase in signal intensity or duration. [IEEE]
bluegrass Music. A type of folk music that originated in the southern United States, typically played on banjos and guitars and characterized by rapid tempos and jazz-like improvisation. [AHD] ["William Smith Monroe (known as Bill) was born near Rosine, Kentucky. His style of music, which we call bluegrass today, probably got its name from the name of his band, the Blue Grass Boys, which was in turn named after his home state of Kentucky, the Bluegrass State." Visual Thesaurus®.
Bluegrass Island Festival (aka Outer Banks Bluegrass Island Festival) Bluegrass festival held yearly on an island off the coast of North Carolina, usually in September.
blue moon For half a century, it's been known as the second full moon in the same calendar month; however, recently this definition was corrected by the editors of Sky & Telescope magazine. The correct definition, they say, is that a blue moon occurs when a season has four full moons, rather than the usual three. Further, they claim the misunderstanding is their fault based on an article they published in 1946. For all the wonderful details, see Once In A Blue Moon.
blue noise See noise color.
Bluetooth The code name given a wireless network protocol, after a 10th century Danish king, Harald Bluetooth, who unified Denmark. The code name was adopted in April, 1998, when Intel and Microsoft formed a consortium between themselves IBM, Toshiba, Nokia, Ericsson and Puma Technology. This protocol promised to bring wireless Internet to the masses, making the Web as ubiquitous as radio and TV. The Bluetooth SIG (special interest group), now numbering over 2000 companies, sees a world where equipment from different manufacturers works seamlessly together using Bluetooth as a sort of virtual cable. Check out the website to read the whole history of Harald Bluetooth and get all the details. Heavily challenged by Wi-Fi, which appears to have already accomplished what Bluetooth is promising. Compare with ZigBee.
blue whales See SPL.
Blumlein, Alan Dower (1903-1942) English engineer who in a short working life span of 15 years wrote or cowrote 128 patents, developed stereophonic sound, designed new uses for microphones, designed a lateral disc-cutting system making modern records possible, developed much of the 405-line high definition television system broadcast in Britain until 1986, and improved radar systems such that they still operated 40 years later. Indeed, a genius by any definition, yet his story had to wait until 1999 to be told completely. Thanks to Robert Charles Alexander, former editor of AudioMedia magazine, a definitive biography now exists. A website of interest is by the BBC and tells the story of how Blumlein's unique recordings have been cleaned up. Go here: Early Stereo Recordings Restored.
Blu-ray Disc A trademark of Sony for their optical disc video recording format developed for recording, rewriting and playback of HDTV, and is predicted to find its way into audio recording use.
blurb Surprisingly old term first used by American humorist Gelett Burgess in 1907. Hit the link for the whole story.
BMC See: biphase mark code.
BNC (bayonet Neill-Concelman) A miniature bayonet locking connector for coaxial cable. It was developed in the late '40s by a collaboration of Paul Neill and Carl Concelman based on a patent granted to the late Dr. Octavio M. Salati. In 1942, while at Bell Labs, Paul Neill developed what became known as the type N connector, named after him, which became a U.S. Navy standard. Carl Concelman, while at Amphenol, developed a bayonet version of the N connector, which became known as the type C connector, after him (the first true 50-ohm connector). Then, together, they developed a miniature bayonet locking version of the C connector and it was named the type BNC connector, after both of them. There is even an improved threaded version called the threaded Neill-Concelman or TNC connector. [Thanks to all who wrote me to help clarify this correct meaning. My condolences to all, who with passion, conviction, and great creativity, truly believe differently. It is a sad but true tale that BNC does NOT stand for "baby N connector," or "bayonet connector," or "bayonet Naval connector," or "British Naval Connector" (sorry Microsoft). For further verification search the web for info on Paul Neill and Carl Concelman.]
Bode, Hendrick Wade (1905-1982) American engineer who pioneered modern Control theory and Electronic Telecommunications.
Bode plot or Bode diagram A method developed by Hendrick Wade Bode to represent the gain and phase of a system as a function of frequency. Usually seen as a plot of log-gain and phase-angle values on a log-frequency scale. See Bode plots and contrast with Nyquist diagrams.
Bo Diddley (1928-2008) Stage name for the American rock legend. Born Otha Ellas Bates, his name was changed to Ellas B. McDaniel by his mother's first cousin, Gussie McDaniel, who raised him. In 1954, band member Billy Boy Arnold, a leading American blues harmonica player, came up with Bo Diddley as a stage name for McDaniel. He described it as a "bowlegged guy, a comical looking guy." Although another possibility is that there is a one-string guitar -- native to the Mississippi Delta where McDaniel was born, called a Diddley Bow, but it is said that Bo Diddley had never played one. [Thanks PT!]
Bogen, David (1889-1974) American Russian immigrant who helped pioneer the hi-fi audio industry.
BOM (bill of materials) A report showing the material costs of a single unit of product; listing of all unit components with part numbers, quantities, and supplier prices. [IEEE]
bonded magnet motors Generic name for a new class of ironless electric motors that do not use iron or ferrite permanent magnets in their construction. Instead they use anisotropic NdFeB (neodymium-iron-boran) bonded magnets (aka neodymium magnets). Of interest to pro audio users since experimental loudspeakers based on bonded magnets are being researched as not only lighter and more eco-friendly but produce audio with lower distortion. See for instance: "Ironless Motor Loudspeaker: Quantization of the Subjective Enhanced Sound Quality" by Ceruti, Daniele; Guyader, Gael; Lemarquand, Guy; Remy, Mathias; Six, Marc-François; Toppi, Romolo, presented at the129th AES Convention, San Francisco, November 4-7, 2010, preprint 8192.
bongo Musical Instrument. One of a pair of connected tuned drums that are played by beating with the hands. [AHD]
Bonnaroo Yearly music festival held at an 700-acre farm in Manchester, TN.
boogaloo Nickname given to Abie "Boogaloo" Ames (1921-2002) in the 1940s for his boogie-woogie (see below) piano style.
boogie 1. To dance to rock music. 2. a. To get going; leave: We're late; let's boogie. b. To move quickly: boogied down the road in their car. n. 1. Strongly rhythmic rock music. 2. Boogie-woogie. [From boogie-woogie below.] [AHD]
boogie-woogie A style of blues piano playing characterized by an up-tempo rhythm, a repeated melodic pattern in the bass, and a series of improvised variations in the treble. [AHD]
bookkeeper "The only English word with three consecutive repeated letters (not including other forms of that word such as bookkeeping." [Oxford Dictionaries.]
Boolean Algebra An algebra in which elements have one of two values and the algebraic operations defined on the set are logical OR, a type of addition, and logical AND, a type of multiplication. [AHD] (After George Boole.)
boom Microphones. A long movable arm used to maneuver and support a microphone. [AHD]
boom box A portable audio system, usually consisting of a radio and a cassette or CD player, with speakers capable of producing loud sound. [AHD]
boost/cut equalizer The most common graphic equalizer. Available with 10 to 31 bands, on 1-octave to 1/3-octave spacing. The flat (0 dB) position locates all sliders at the center of the front panel. Comprised of bandpass filters, all controls start at their center 0 dB position and boost (amplify or make larger) signals by raising the sliders, or cut (attenuate or make smaller) the signal by lowering the sliders on a band-by-band basis. Commonly provide a center-detent feature identifying the 0 dB position. Proponents of boosting in permanent sound systems argue that cut-only use requires adding make-up gain that runs the same risk of reducing system headroom as boosting.
boot Computer Science. The process of starting or restarting a computer. [AHD]
boot loader Computer Science. A small program that starts (loads) other data and programs into RAM where they are executed.
bop 1. A post-World War II style of jazz characterized by rhythmic and harmonic complexity, improvised solo performances, and a brilliant style of execution. [AHD] The word "bebop" was shortened to "bob" with Charlie Parker's 1947 recording "Bongo Bop." [Decharne] 2. "Playing bop is like playing Scrabble with all the vowels missing." Duke Ellington, Look August 10, 1954. [Crystal]
Bose, Amar (1929-2013) American engineer, academic professor and entrepreneur, who founded Bose Corporation in 1964.
Boston Calling Festival Music festival featuring new and established acts held in—wait for it—yeah, Boston, MA.
Botanicus Interacticus A touch-control technology named Touché, invented by Disney scientists at Carnegie Mellon that can be used to play a houseplant like a musical instrument. Hit the link to watch the amazing video.
BottleRock A festival combining wine, music and food held in Napa, California.
Boucherot, Paul (1869-1943) French engineer who studied the phenomena of electric conduction, introducing the concept of reactive power and inventing the synchronous electric motor in 1898. He also studied the thermal energy of the seas. The Claude-Boucherot Process described a scheme to power a turbo-alternator using warm seawater from tropical oceans to produce steam in a vacuum chamber. Theorem of Boucherot: In an AC electrical network, the total active power is the sum of the individual active powers, the total reactive power is the sum of the individual reactive powers, but the total apparent power is NOT equal to the sum of the individual apparent powers.
Boucherot cell After Paul Boucherot above; see Zobel network.
boundary microphone See PZM
bouzouki (also bazouki) Musical Instrument. A Greek stringed instrument having a long fretted neck and usually pear-shaped body. [AHD]
Bowditch curve See Lissajous figure.
Bozak, Rudy See Bozak.
BPL (broadband over power lines) General term for any of the "carrier-current" systems that conduct signals over existing electrical wiring or power lines.
BPM Exposition. European expo focusing on DJing, club culture & electronic music.
Bps (always uppercase B) Abbreviation for bytes per second.
bps (always lowercase b) Abbreviation for bits per second.
BPSK (binary phase-shift keying) (aka bi-phase modulation) A specific form of PSK that defines two states of carrier phase that are digitally encoded in a binary stream. The states have a change in phase of 180 degrees that correspond to the 0 and 1 binary state. [IEEE]
Braille, Louis (1809-1852) French musician, educator, and inventor of a writing and printing system for blind or visually impaired people (1829). He lost his sight at the age of three. [AHD] His braille system was first developed for blind musicians.
bray 1. To utter the loud, harsh cry of a donkey. 2. To sound loudly and harshly: The foghorn brayed all night. [AHD]
breathing Dynamics Processors. The audible effect caused by varying noise (or hiss) levels down around the noise floor usually caused by turning on and off gates and expanders. [Izhaki] Technically it is a modulation of the noise floor.
breve Music. A note equivalent to two whole notes. Also: 1. A symbol ( ? ) placed over a vowel to show that it has a short sound, as the a in bat. 2. A curved mark used to indicate a short or unstressed syllable of verse. [AHD]
brewer See zymurgy.
bridge 1. In communications networks a bridge is a device that connects two or more different networks and forwards packets between them; specifically a device that (a) links or routes signals from one ring or bus to another, or from one network to another, (b) may extend the distance and capacity of a single LAN system, (c) performs no modification to packets or messages, (d) operates at the data-link layer of the OSI--Reference Model (Layer 2), (e) reads packets, and (f) passes only those with addresses on the same segment of the network as the originating user. 2. A functional unit that interconnects two local area networks that use the same logical link control (LLC) procedure, but may use different medium access control (MAC) procedures. 3. A balanced electrical network, e.g., a Wheatstone bridge. Contrast with hub.
bridged amplifier See BTL.
bridge-tied load See BTL.
briole Theater. Name for the adjustable wire ropes used for theater rigging, e.g., loudspeakers, lighting, scenery, etc.
British Summer Time See: BST.
broadband Also wideband, a transmission medium having a bandwidth greater than a traditional telephone (speech) channel (4 kHz). [Some argue that to be "broadband" the medium must support 20 kHz.] The most common broadband medium is coaxial cable carrying multiple audio, video and data channels simultaneously. Each channel takes up a different frequency on the cable. There will be guardbands, or empty spaces, between the channels to make sure each channel does not interfere with its neighbor. The most common example is the CATV cable. Contrast with baseband.
broadcasting Networks. A message sent out available for anyone to receive (just like radio broadcast), i.e., sending the same message to multiple recipients, as opposed to multicasting. Broadcasting sends a message to everyone on the network; multicasting sends a message to a specified few.
brown noise See noise color.
brown note Music. An urban myth that there existed a low frequency note that when played at high levels would make listeners loose bowel control. Exposed as false by Meyer Sound in a TV Myth Busters episode. Compare with blue note.
Brubeck, Dave (1920-2012) American jazz giant, designated a "Living Legend" by The Library of Congress.
Brunswick Panatrope See: Panatrope.
B&S gauge (Brown & Sharpe) See AWG.
BSI (British Standards Institute) The National Standards organization responsible for coordinating standards preparation for sound equipment in the UK.
BST (British Summer Time) Music festival held yearly in Hyde Park, London.
B-taper See potentiometer.
BTL (bridge-tied load) Amplifiers. An amplifier configuration where the loudspeaker load is connected between the two hot outputs of two amplifiers operating in bridged amplifier mode, i.e., anti-phase, where the output of one amplifier drives the the second amplifier out of phase, or inverted, and operates at unity gain. Thus the second amplifier (usually the second channel of a two channel design) acts as a current amplifier (with inverting voltage). This doubles the output voltage (one-half from the first amplifier and one-half from the second amplifier) and theoretically produces four times the power output (double the voltage equals double the current equals four times the power). However this virtually never happens in practice since the amplifier power supply runs out of current long before four times the power is reached. Typically, amplifiers operating in bridged amplifier mode deliver twice their single-ended output power. Semiconductor audio power amplifiers use BTL configurations as a way to maximize power output from the small voltage sources found in internet appliances and automotive applications.
BTU (British thermal unit) 1. The quantity of heat required to raise the temperature of one pound of water from 60° to 61°F at a constant pressure of one atmosphere. 2. The quantity of heat equal to 1/180 of the heat required to raise the temperature of one pound of water from 32° to 212°F at a constant pressure of one atmosphere. [AHD] The Btu is equivalent to 0.252 kilogram-calorie or 1055 joules. And 1 watt equals 3.41 BTUs/hour.
buckslip (also buck slip) Publishing. A small dollar-bill size (i.e., a buck) printed insert blown into magazines during the binding stage. Common in the direct mail world. Office memo. A routing slip used especially in military offices to indicate the persons to whom the attached material is to go and usually the kind of action to be taken with such material. [Merriam-Webster]
Buddha Bar A restaurant/club franchise begun in 1995 by Raymond Visan with his first location in Paris.
buds See: personal monitors
buffer In data transmission, a temporary storage location for information being sent or received.
buffer amplifier The IEEE dictionary defines buffer amplifier as "An amplifier in which the reaction of output-load-impedance variation on the input circuit is reduced to a minimum for isolation purposes." (Vacuum tube cathode followers and solid-state emitter followers are two examples.) This is a bit confusing, but one thing is clear, it says that at the most fundamental level a buffer amplifier isolates (buffers) the loading effects (impedance) of two stages. It separates them, making them independent. In analog designs, buffer amplifiers are used for just this purpose. If the next circuit stage in a design has impedance characteristics that are detrimental to the preceding stage then a buffer amplifier minimizes this interaction. And its use is not confined to analog design, digital circuits use buffers to minimize similar loading effects.
The term "amplifier" comes about from the fact that most buffer amplifiers also provide either voltage or current gain. In this sense, a normal audio power amplifier can be called a buffer amplifier - it buffers your preamp from your very low impedance loudspeakers. [Historical Note: Sometimes a buffer amplifier provides speed as well as isolation. In the mid '70s, National Semiconductor offered in their specialty hybrid circuits line, a product simply named "Fast Buffer," whose purpose was to provide impedance isolation, but could do so at high megawiggle speeds (not a trivial task back then), and if that wasn't good enough, they also offered a "Damn Fast Buffer," that could really get the job done (true story).] As can be seen, the term buffer amplifier is a bit vague: it provides isolation, that much is sure, however, it may also offer voltage gain, current gain, or both. And it may even provide an unbalanced-to-balanced function, or vice-versa.
bug A surprisingly old word used most often to connote a problem with a program or computer. From the 1896 edition of Hawkin's New Catechism of Electricity (Theo. Audel & Co.) comes this definition: "The term `bug' is used to a limited extent to designate any fault or trouble in the connections or working of electric apparatus." To get rid of see Agans.
Bulwer-Lytton Fiction Contest A whimsical literary competition that challenges entrants to compose the opening sentence to the worst of all possible novels. Created by Professor Scott Rice, English Department, at San Jose State University in 1982, the contest is still sponsored by the college. The name comes from Edward George Earle Bulwer-Lytton, who wrote the famous line "It was a dark and stormy night ..." as the opening words in his novel Paul Clifford (1830). Check it out -- great fun.
When Wilkie Collins's detective novel The Woman in White appeared in 1860, it created a considerable stir. A feature much remarked upon was the villain, Count Fosco. One lady reader, however, was not so impressed and wrote to tell Collins, "You really do not know a villain. Your Count Fosco is a very poor one." She then offered to supply Collins with a villain next time he wanted one. "Don't think that I am drawing upon my imagination. The man is alive and constantly under my gaze. In fact, he is my husband." The writer was Bulwer-Lytton's wife. [Bartlett's Book of Anecdotes]
bumbershoot 1. An umbrella. Derived from an alteration of umbrella + alteration of (para)chute. [AHD] 2. A Seattle arts festival held each Labor Day weekend, featuring over 2,500 artists including comedians, dancers, painters, poets, sculptors, tightrope walkers, acrobats, filmmakers, bookbinders, DJs, thespians, and musicians of every genre -- from classical to hip-hop.
bump-in; bump-out LIve Audio. Aussie slang for load-in; load-out.
Bundle The shortened form for CobraNet® Bundle; always with a capital B to differentiate it from a bundle of wires.
burnt-in time code See time code.
Burrus LED Electronics. A surface-emitting LED with a hole etched to accommodate a light-collecting fiber, named after its inventor, Charles A. Burrus of Bell Labs. [JAES]
burst error A large number of data bits lost on the medium because of excessive damage to or obstruction on the medium.
burst noise See popcorn noise.
bus One or more electrical conductors used for transmitting signals or power from one or more sources to one or more destinations. Often used to distinguish between a single computer system (connected together by a bus) and multi-computer systems connected together by a network.
buss To kiss. [AHD]
Butterworth filter A type of electronic filter characterized by having a maximally flat magnitude response, i.e., no amplitude ripple in the passband. [Contrast with Chebyshev] This circuit is based upon Butterworth functions (or Butterworth polynomials). [For the mathematically inclined, these polynomials represent a specialized solution to a general MacLaurin series based upon a Taylor series expansion. Named after Stephen Butterworth, a British engineer who first described this response in his paper "On the Theory of Filter Amplifiers," Wireless Engineer, vol. 7, 1930, pp. 536-541. Eleven years later, V.D. Landon coined the phrase maximally flat in his paper "Cascade Amplifiers with Maximal Flatness," RCA Review, vol. 5, 1941, pp. 347-362.]
buzznack An old organ, out of order and playing badly. [Kacirk]
bypass capacitor (also decoupling capacitor) Electronics. A capacitor connected from (usually) power supply lines to ground, for the purposes of diverting AC ripple voltages and currents to ground in order to keep the DC supple lines clean and quiet.