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Dictionary of Audio Terminology - T

T-1 (trunk level 1) - A digital transmission scheme utilizing two twisted-pair capable of handling a minimum of 24 voice channels. Used for connecting networks across remote distances.

tablature - A system of notation using letters, symbols, or other visual cues instead of standard notation to indicate how a musical piece is to be played. For example, guitar or banjo tablature typically consists of a diagram of the strings with finger positions indicated by numerals corresponding to the appropriate frets.

talkback – (1) A recording console feature where a microphone mounted on the console allows the engineer to speak with the musicians during sessions -- a very useful feature when the console is located in a soundproof control room, or out in the audience for sound reinforcement systems.

talk box - A poor man's vocoder. Popularized by Peter Frampton and Joe Walsh in the '70s.

talkover - A term and function found on DJ mixers allowing the DJ to speak over the program material by triggering a ducker. Compare with voiceover.

tangential mode - Sound reflecting between four surfaces (i.e., two sets of parallel walls). Compare with axial mode and oblique mode.

taper - The relation, with respect to a potentiometer, between slider position and resistance is generally either linear or logarithmic (aka "audio taper"). A letter code ("A" taper, "B" taper, etc.) may be used to identify which taper is used, but the letter code definitions are variable over time and between manufacturers.

Tappan, Peter - (b. 1928-2007) American physicist and acoustical engineer whose work background included Bolt, Beranek and Newman, and Kirkegaard & Associates where he was a principal consultant and vice president. The author of "Shattering Goblets with Amplified Singing," he consulted with Memorex for their famous "Is it Live or is it Memorex" commercial.

taste test or tongue test - ‘Not Recommended’ - An actual voltage testing method recommended by Terrell Croft in his book.

"The presence of low voltages can be determined by 'tasting.' The method is feasible only where the pressure is but a few volts and hence is used only in bell and signal work. Where the voltage is very low, the bared ends of the conductors constituting the two sides of the circuit are held a short distance apart on the tongue. If voltage is present a peculiar mildly burning sensation results which will never be forgotten after one has experienced it. The 'taste' is due to the electrolytic decomposition of the liquids on the tongue which produces a salt having a taste. With relatively high voltages, possible 4 or 5 volts, due to as many cells of battery, it is best to first test for the presence of voltage by holding one of the bared conductors in the hand and touching the other to the tongue. Where a terminal of the battery is grounded, often a taste can be detected by standing on moist ground and touching a conductor from the other terminal to the tongue. Care should be exercised to prevent the two conductor ends from touching each other at the tongue, for if they do a spark can result that may burn." And from the same book comes these words of wisdom for testing for the presence of electricity by touching the two conductors:

"Electricians often test circuits for the presence of voltage by touching the conductors with the fingers. This method is safe where the voltage does not exceed 250 and is often very convenient for locating a blown-out fuse or for ascertaining whether or not a circuit is alive. Some men can endure the electric shock that results without discomfort whereas others cannot. Therefore, the method is not feasible in some cases."

Another interesting item is the case of a Swiss musician who "tastes" combinations of notes as distinct flavors, according to a report in the science journal Nature. The young woman is a synaesthete and when she hears tone intervals, the difference in pitch between two tones, she not only can see the musical notes as different colors but can taste the sounds.

Tau - In professional mathematical literature the symbol for the Golden Ratio, or Golden Rectangle, but now phi is the more common symbol.

taut-band - Consisting of a permanent magnet and moving coil. Favored for its friction free suspension, allowing precision measurements.

TCP/IP (transmission control protocol/internet protocol) - A set of protocols developed by the Department of Defense in the '70s to link dissimilar computers across many kinds of networks and LANs. Popular with Ethernet users.

TDIF (Teac digital interface format) - Tascam's (Teac) 8-channel digital audio interface to their DA-88 digital multitrack recorder, using unbalanced signal transmission and a DB-25 type connector.

TDM (time division multiplexing) - A transmission interleaving technique where multiple sources, say, data, voice and video, are broken up into pieces and each piece is assigned a unique time slot with no overlap between pieces. This allows simultaneous transmission of multiple signals over a common path.

TDS (time-delay spectrometry) - A sound measurement theory and technique developed in 1967 by Richard C. Heyser at the Jet Propulsion Laboratories of the California Institute of Technology.

TEA (Themed Entertainment Association) - "The only international non-profit association representing the world's leading creators, developers, designers and producers of compelling places and experiences. Our members bring the experience of engaging storytelling and entertainment to a vast number of casinos, restaurants, retail stores, museums, zoos, theme parks and an ever-growing list of destinations that aim to bring a higher level of visitor experiences world wide." Another great resource for audio contractors, integrators, etc.

TEC (Technical Excellence and Creativity) - Founded in 1985, this foundation is a 501(c) (3) public benefit corporation, dedicated to promoting excellence in audio, video, music and other communications media arts.

TEDS (Transducer Electronic Data Sheet) - An electronic microphone system (applies to any transducer so fitted but microphones are relevant to this listing). Developed and standardized as IEEE P1451.4, it is an embedded IC and software system that allows the user to read stored information about a particular microphone -- make, model, serial number, calibration date, sensitivity, capacitance, impedance, etc.

TEF (time-energy-frequency) -The term adopted to describe the entire spectrum of TDS measurements, including energy-time curves. Popularized by Richard Heyser through his participation in Synergetic Audio Concepts seminars. Made practical in 1979 by the Techron division of Crown International -- Cal Tech's first TDS licensee, and introduced as the TEF System 10.

tele - Distance; distant (Greek tele- meaning far off.)

telecommunication - Communicating over a distance by wire, fiber or wireless means.

teleconferencing - An audio conference held by three or more persons over a distance. Normal usage refers to voice conferencing, also termed audioconferencing that includes all forms of audio. The term is sometimes extended to include video and document, or data, conferencing. Note that the term does not mean telephone conferencing, but rather distance conferencing, although telephone lines are often used.

Telegraphone - Invented by Danish engineer Valdemar Poulsen (1869-1942) in 1898. It received and stored audio signals by magnetizing steel wire and is recognized as the first wire recorder.

telemedicine - A specialized form of videoconferencing optimized for medical uses. Also referred to as medical conferencing, it allows distance learning in medical education and delivers health care (including assisted medical operations) to patients and providers at a distance.

telephone hybrid - essential functional component of the Public Switched Telephone Network (PSTN). The term also describes the piece of equipment used in broadcast facilities to enable the airing of telephone callers.

telepresence - This is where multiple people sit side by side across a table at each end of a video conference (with variants) - as if they were across the table from each other. The audio is imaged so the talker's voice seems to originate from the direction of each talker.

Telharmonium - Invented and patented (US patent #580,035) by Thaddeus Cahill, in the 1890s, an amazing monstrosity weighing 7 tons that was the first device to successfully send music through a telephone connected to something similar to a gramophone cone that could be heard by an audience.

temperament - The building up of musical scales.

tempo - The speed at which music is or ought to be played, often indicated on written compositions by a descriptive or metronomic direction to the performer.

temporal - Of, relating to, or limited by time.

temporal masking - A specific kind of masking where time separates arriving signals. Masking of a later arriving signal due to an earlier one is called forward masking. The effects of a loud first sound can last long enough to mask a later arriving softer one (periods less than 500 ms and greater than 10 dB loudness differences).

The opposite effect where an earlier sound is masked by a later arriving one is called backward masking, i.e., the second arriving event covers up the first arriving signal. This is only possible because the ear requires time to form an echoic image before it is processed by the central nervous system. If a later sound is much louder it can take precedence over an earlier arriving one (within about 100 to 200 ms).

terahertz - Abbr. THz One trillion (10E12) hertz.

TERC (tuned electromagnetic resonance collar) - A non-acoustic voice sensor device developed by the Spinlab (signal processing and information networking laboratory) at Worcester Polytechnic Institute in Massachusetts that can create speech from an unspoken voice.

terminal strips - type of electrical connector where a wire is clamped down to metal by a screw. The wire is sometimes just stripped of electrical insulation at the end, and is bent in a U or J shape to fit around the shaft of the screw. Alternatively, a lug can be crimped onto the end of the wire to protect it. Setscrews are also used, as in a luster terminal or lustre terminal, but lugs will not fit into them. For both lugs and bare wire, the screw is tightened for a secure connection.

Tesla - Abbr. T - The unit of magnetic flux density in the International System of Units, equal to the magnitude of the magnetic field vector necessary to produce a force of one newton on a charge of one coulomb moving perpendicular to the direction of the magnetic field vector with a velocity of one meter per second. It is equivalent to one weber per square meter. [After Nikola Tesla.]

Tesla, Nikola - (b. 1856-1943) Serbian-born American electrical engineer and physicist who discovered the principles of alternating current (1881) and invented numerous devices and procedures that were seminal to the development of radio and the harnessing of electricity.

tetrahedron - A polyhedron with four faces. Invented by Michael Gerzon and Peter Craven, a microphone design based on tetrahedron geometry used in Ambisonics surround sound recordings. Available from Soundfield.

Tetrode - A type of vacuum tube having two grids, where one is used to reduce feedback related instabilities and oscillations. A tetrode has four elements: plate, cathode, control grid and screen grid.

THD (total harmonic distortion) - A measurement technique rarely used, but often confused with the THD+N technique described below. Many people mistakenly refer to a "THD" measurement when they really mean the "THD+N" technique. (For completeness and the abnormally curious: a true THD measurement consists of a computation from a series of individual harmonic amplitude measurements, rather than a single measurement. "THD" is the square root of the sum of the squares of the individual harmonic amplitudes. And the answer must specify the highest order harmonic included in the computations; for example, "THD through 8th harmonic."

THD+N (total harmonic distortion plus noise) - The most common audio measurement. A single sine wave frequency of known harmonic purity is passed through the unit under test, and then patched back into the distortion measuring instrument. A measurement level is set; the instrument notches out the frequency used for the test, and passes the result through a set of band-limiting filters, adjusted for the bandwidth of interest (usually 20-20 kHz). What remains is noise (including any AC line [mains] hum or interference buzzes, etc.) and all harmonics generated by the unit. This composite signal is measured using a true rms detector voltmeter, and the results displayed. Often a resultant curve is created by stepping through each frequency from 20 Hz to 20 kHz, at some specified level (often +4 dBu), and bandwidth (usually 20 kHz; sometimes 80 kHz, which allows measurement of any 20 kHz early harmonics). [Note that the often-seen statement: "THD+N is x%," is meaningless. For a THD+N spec to be complete, it must state the frequency, level, and measurement bandwidth.] While THD+N is the most common audio test measurement, it is not the most useful indicator of a unit's performance. What it tells the user about hum, noise and interference is useful; however that information is better conveyed by the signal-to-noise (S/N) ratio specification. What it tells the user about harmonic distortion is not terribly relevant simply because it is harmonically related to the fundamental, thus the distortion products tend to get masked by the complex audio material. The various intermodulation (IM) distortion tests are better indicators of sonic purity.

theremin (aka aetherphone) - Considered the first electronic musical instrument, invented in 1919 by Russian born Lev Sergeivitch Termen, which he anglicized to Leon Theremin. The theremin is unique in that it is the only musical instrument played without being touched. Interestingly, when granted a US Patent in 1928, there were 32 prior patents referenced, going all the way back to Lee De Forest. A theremin works by causing two oscillators to "beat" together. The beat frequency equals the difference in frequency between the two signals. Beats are a physical phenomenon occurring in the air when sounds are mixed. A theremin uses one oscillator operating well above the upper limit of human hearing as a reference tone, and another oscillator whose frequency is varied by the proximity of a human hand, for instance, to a capacitive sensing element shaped like an antenna. A typical machine has two antennas and you play it by moving your hands nearer to and farther from the antennas. One antenna controls the volume of the sound, while the other controls the frequency, or pitch, of the sound. Used together you can creates sounds that can range from being very sci-fi-ish -- a sort of quivering sound -- as heard in early sci-fi movies like The Day the Earth Stood Still, to very complex jazz licks. The theremin even appears as Dr. Hannibal Lecter's favorite instrument in Thomas Harris' bestseller Hannibal (Delacorte, 1999). It was the theremin that got Bob Moog (inventor of the Moog Synthesizer and considered the father of modern electronic music) interested in electronic music. Moog Music now makes some of the world's best theremins.

thermal noise - electronic noise generated by the thermal agitation of the charge carriers (usually the electrons) inside an electrical conductor at equilibrium, which happens regardless of any applied voltage. The generic, statistical physical derivation of this noise is called the fluctuation-dissipation theorem, where generalized impedance or generalized susceptibility is used to characterize the medium.

thermion - An electrically charged particle, especially an electron, emitted by a conducting material at high temperatures. Basis for the thermionic valve, or vacuum tube.

thermionic valve - device that relies on the flow of electric current through a vacuum.

thermoacoustics - "The study of the conversion of acoustic energy -- compression waves in a gas (sound) -- into heat energy and vice versa. Acoustic energy can be harnessed in sealed systems and used to create powerful heat engines, heat pumps, and refrigerators. Thermoacoustic devices use these compression waves to replace mechanical pistons, crankshafts, and valves, reducing the number of moving parts in their design and making them simple, reliable machines. Thermoacoustic cryocoolers generally have two major sections to their design: an electroacoustic transducer (like a loudspeaker) and a coldhead."

thermophone - A telephone involving heat effects, as changes in temperature (hence in length) due to pulsations of the line current in a fine wire connected with the receiver diaphragm.

Thevenin's Theorem - In simple terms, states that a complex linear circuit (i.e., no exponents or roots in its defining equations) can be replaced by a single voltage source and a series resistor. [After Léon Charles Thévenin.]

Thévenin, Léon Charles - (b. 1857-1926) French telegraph engineer most famous for his Theorem.

third-harmonic distortion - The standard test used on analog magnetic tape recorders to determine the maximum output level (MOL), which was defined to occur at the magnetization level at which a recorded 1 kHz sine wave reached "3% third-harmonic distortion." Of course, third-harmonic distortion is nothing more than a measurement of the amplitude of the third harmonic of the input frequency and is the most prominent distortion component in analog magnetic recording systems. The third-harmonic level was used as a convenient figure-of-merit because the 2nd harmonic is difficult to hear, since it tends to reinforce the pitch of the fundamental. The 3rd harmonic is easy to detect on pure tones (although less so on music), thus it makes a good benchmark for comparing sound "off tape" with the original. The distorted tone has an edge to it, containing a component one octave and a quint (interval of a fifth in music) above the fundamental. For this reason the third-harmonic is also called a musical twelfth. Here's the interesting twist. This test was commonly abbreviated and listed on the specification sheet as "THD." Which, of course, was mistaken to mean "total harmonic distortion" instead of "third harmonic distortion." This led to it being mistakenly shortened to just "distortion," so you still find old analog tape data sheets, and many text books defining MOL as the point at which there exists "3% distortion," instead of the correct reference to "3% third-harmonic distortion" -- quite different things.

third-octave - Term referring to frequencies spaced every three octaves apart. For example, the third-octave above 1 kHz is 8 kHz. Commonly misused to mean one-third octave. While it can be argued that "third" can also mean one of three equal parts, and as such might be used to correctly describe one part of an octave split into three equal parts, it is potentially too confusing. The preferred term is one-third octave.

Throb - Term for noise in the 8 Hz to 31.5 Hz range.

Thunderbolt™ - Intel developed interconnect technology first used in Apple MacBook Pro notebooks.

Thuras Albert L. - American engineer most famous as the inventor of the bass reflex loudspeaker. Thuras filed patent No. 1,869,178, "Sound Translating Device," on Aug. 15, 1930, granted July 26, 1932, for the bass-reflex principle while working at Bell Labs.

THX® Ltd. - (formerly a division of Lucasfilm Ltd.) term meaning several things: (1) THX Digital Cinema: audio playback design and certification program for commercial cinema theaters; (2) THX Cinema: audio playback specification for home cinema systems; (3) THX Home: approved audio/video playback equipment meeting their standards of quality and performance, as well as DVDs, laserdiscs and VHS tapes mastered by them to meet their quality and performance standards. New categories are THX Mobile and THX Games. The term comes from two sources: George Lucas's first film THX-1138 (commercial version), and a somewhat tongue-in-cheek reference to Tomlinson Holman's eXperiment, after their original technical director, patentee and creative force behind all the above (who now runs TMH Corporation).

THX Surround EX - Surround-sound format that matrix-encodes a third surround channel into the existing left and right surround channels in a Dolby Digital signal. This channel drives a center rear loudspeaker. Compare with DTS-ES.

thyristor - a solid-state semiconductor device with four layers of alternating N and P-type material. They act as bistable switches, conducting when their gate receives a current trigger, and continue to conduct while they are forward biased (that is, while the voltage across the device is not reversed).

ti - The seventh tone of the diatonic scale in solfeggio.

TIA (Telecommunications Industry Association) - Created in 1988 by a merger of the US Telecommunications Suppliers Association (USTSA) and the EIA's Information and Telecommunications Technologies Group (EIA/ITG). This organization works with the EIA in developing technical standards and collecting market data for the telecommunication industry.

TIM (Transient intermodulation distortion) - Occurs in amplifiers that employ negative feedback when signal delays make the amplifier incapable of correcting distortion when exposed to fast, transient signals.

timbre - (pronounced "tambur") (1) The quality of a sound that distinguishes it from other sounds of the same pitch and volume. (2) The distinctive tone of an instrument or a singing voice.

time – (1) a. A nonspatial continuum in which events occur in apparently irreversible succession from the past through the present to the future. b. An interval separating two points on this continuum. c. A number, as of years, days, or minutes, representing such an interval. d. A similar number representing a specific point on this continuum, reckoned in hours and minutes. (2) a. The characteristic beat of musical rhythm: three-quarter time. b. The speed at which a piece of music is played; the tempo.

Time-Align® - Trademark of Ed Long for his proprietary crossover techniques.

Timecode - A sequence of discrete numeric codes occurring at regular intervals used to determine time. Various time code formats and methods exist. The following are the most popular pro audio applications:

• SMPTE/EBU. A standardized 80-frame word embedded as part of motion picture or sound recording (standardized for recording by SPARS). A specific identity or address is assigned to each moment of time in a recording, broken down into HOURS:MINUTES:SECONDS:FRAMES.

• MIDI. MIDI time code (MTC), is used to synchronize MIDI systems with the rest of the audio and video world.

• AES3 or AES/EBU. Within this standardized digital audio serial interface are provisions for time data.

• Additional recording time code methods are Linear or Longitudinal Time Code (LTC), Vertical Interval Time Code (VITC), Burnt-In or Burned In Time Code.

• Time codes for purposes other than video and audio production include Inter-range instrumentation group (IRIG), Global Positioning System (GPS), Network Time Protocol (NTP), and Radio Clocks.

time constant - usually denoted by the Greek letter τ (tau), is the risetime characterizing the response to a time-varying input of a first-order, linear time-invariant (LTI) system. The time constant is the main characteristic unit of a first-order LTI (linear time-invariant) system.

time-difference microphone technique - uses two parallel omnidirectional microphones some distance apart, so capturing time-of-arrival stereo information as well as some level (amplitude) difference information, especially if employed close to the sound source(s).

tinnitus - A sound in one ear or both ears, such as buzzing, ringing, or whistling, occurring without an external stimulus and usually caused by a specific condition, such as an ear infection, the use of certain drugs, a blocked auditory tube or canal, or a head injury.

token ring - A LAN baseband network access mechanism and topology in which a supervisory "token" (a continuously repeating frame [group of data bits] transmitted onto the network by the controlling computer; it polls for network transmissions) is passed from station to station in sequential order. Stations wishing to gain access to the network must wait for the token to arrive before transmitting data. In a token ring topology, the next logical station receiving the token is also the nest physical station on the ring. This mechanism prevents collisions on this type of network. Normally connected as a star-wired ring where each station is wired back to a central point known as the multistation access unit (MAU). The MAU forms a ring of the devices and performs the back-up function of restoring the ring should one of the devices crash or lose its cable connection.

tone – (1) a. A sound of distinct pitch, quality, and duration; a note. b. The interval of a major second in the diatonic scale; a whole step. c. A recitational melody in a Gregorian chant. (2) a. The quality or character of sound. b. The characteristic quality or timbre of a particular instrument or voice.

tone controls - The term most often referring to a two-band shelving equalizer offering amplitude control only over the highest (treble, from music, meaning the highest part, voice, instrument, or range) frequencies, and the lowest (bass, from music, meaning the lowest musical part) frequencies. Sometimes a third band is provided for boost/cut control of the midband frequencies.

ToneRite® - Registered trademark of the company and their patented electronic devices designed to simulate years of playing on stringed instruments to obtain the optimum sound without having to actually play them in real time. They call it a play-in device. This is done by a device that emits infrasonic sounds that create vibrations that simulate real playing. While still controversial, it is finding many customers.

topology - The interconnection pattern of nodes on a network. The logical and/or physical arrangement of stations on a network (e.g., star topology; tree topology; ring topology; bus topology, etc.). The geometric pattern or configuration of intelligent devices and how they are linked together for communications.

Torick, Emil - (b. 1931-2010) American scientist and musician most notable for his distinguished career of nearly 30 years at CBS as well as being a Fellow, Honorary Member and past-President of the AES.

toroid - The name for any doughnut-shaped body.The shortened popular name for the doughnut-shaped (toroidal) transformers common to audio equipment; favored for their low hum fields.

TOSLINK (Toshiba link) - A popular consumer equipment fiber optic interface based upon the S/PDIF protocol, using an implementation first developed by Toshiba.

total harmonic distortion - measurement of the harmonic distortion present and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency.

T-pad - attenuator circuit in electronics whereby the topology of the circuit is formed in the shape of the letter "T".

T-powering - Named after the German word Tonaderspeisung, It is a special purpose powering system designed for T-power microphones, usually electret or condenser designs. Originally standardized as DIN 45 595.

TPDF (triangular probability density function or triangular dither) -describes a probability density function shaped like a triangle, instead of the more often seen bell-shaped curve. For dither use, the extremes represent the maximum possible quantization error of ±1 LSB. Also very popular is a variant known as shaped triangular or high-passed TPDF, which is essentially high-pass filtered triangular dither that places most of the dither energy at higher frequencies making it less audible.

tracking power amplifiers - A term used to describe audio power amplifier designs utilizing a variable power supply for the output, and a means of controlling the power supply based upon the input signal.

transcendental number – (1) Not capable of being determined by any combination of a finite number of equations with rational integral coefficients. (2) Not expressible as an integer or as the root or quotient of integers. Used of numbers, especially nonrepeating infinite decimals.

transconductance - The ratio of the current at the output port and the voltage at the input port, measured in siemens.

transducer - A device, such as a microphone, or loudspeaker, that converts input energy of one form into output energy of another.

transfer function - For a linear system, the ratio of the LaPlace Transform of the output to that of the input with no other input signals and initial conditions zero.

transform switch - This switch selects either phono or line, on a DJ mixer, as the channel source, but is commonly used for transforming, or quickly gating the source on and off.

Transformer - A passive component that uses electromagnetic induction to increase or decrease alternating electric energy (voltage and current), usually consisting of two wirewound coils (windings) inductively coupled. A step-up transformer raises voltage and a step-down transformer lowers voltage.

transient discontinuous sound - An intermittent sound decaying with time, especially as a simple exponential function of time. Characterized as a passing burst of sound marked by breaks or interruptions.

transient response - The reaction of an electronic circuit, or electromechanical device, or acoustic space to a non-repetitive stimulus such as a step or impulse response. It is the result to a sudden change in the input that is nonperiodic. For example, percussive instruments produce primarily transient sounds. The transient stimulus and resulting response are characterized by the amplitude and the rise time (and fall time if it is an impulse), overshoot, and settling time. The standard reference is to note the maximum amplitude and the time required to reach within 10% of the steady-state value.

Transistor – (1) An active semiconductor device with three or more terminals. It is an analog device. (2) A semiconducting device for controlling the flow of current between two terminals, the emitter and the collector, by means of variations in the current flow between a third terminal, the base, and one of the other two.

Transonic - Of or relating to aerodynamic flow or flight conditions at speeds near the speed of sound.

transversal equalizer - A multi-band variable equalizer using a tapped audio delay line as the frequency selective element, as opposed to bandpass filters built from inductors (real or synthetic) and capacitors. The term "transversal filter" does not mean "digital filter." It is the entire family of filter functions done by means of a tapped delay line. There exists a class of digital filters realized as transversal filters, using a shift register rather than an analog delay line, with the inputs being numbers rather than analog functions.

Trautonium - An early synthesizer from 1928. A monophonic instrument using a stretched wire over a resistor like a ribbon controller, with added pedals and keys.

traveling wave - Something vibrating creates a wave pattern that travels through a medium from one place to another.

treble clef - A symbol indicating that the second line from the bottom of a staff represents the pitch of G above middle C. Also called G clef.

tree topology - A LAN topology that recognizes only one route between two nodes on the network. The map resembles a tree or the letter T.

tremolo - (1) A tremulous effect produced by rapid repetition of a single tone. A similar effect produced by rapid alternation of two tones. (2) A device on an organ for producing a tremulous effect. (3) A vibrato in singing, often excessive or poorly controlled.

triamp, triamplified, or triamplification - Term used to refer to a 3-way active crossover where the audio signal is split into three paths, and using separate power amplifier channels for each driver.

triangle wave - A periodic waveform characterized by a 50% duty cycle and a Fourier series consisting of odd-ordered, equal phase, sinusoidal harmonic components of its fundamental frequency with amplitudes (coefficients multiplying the magnitude of the fundamental sine wave) equal to 1/n², where n equals the harmonic number. Therefore the first few harmonic amplitudes are 1/9, 1/25, 1/49, 1/81, etc.

TRIAC (Triode for Alternating Current) - a genericized tradename for an electronic component that can conduct current in either direction when it is triggered (turned on), and is formally called a bidirectional triode thyristor or bilateral triode thyristor.

Triax- Triaxial Cable, often referred to as triax for short, is a type of electrical cable similar to coaxial cable, but with the addition of an extra layer of insulation and a second conducting sheath. It provides greater bandwidth and rejection of interference than coax, but is more expensive. It is most commonly used in the television industry as a connecting cable between a camera and its CCU.

triboelectric effect - An electrical charge produced by friction between two objects.

Triode - Electronic amplification device having three active electrodes. The term most commonly applies to a vacuum tube (or valve in British English) with three elements: the filament or cathode, the grid, and the plate or anode. The triode vacuum tube was the first electronic amplification device, which propelled the electronics age forward, by enabling amplified radio technology and long-distance telephony.

triple point of water - A system is at the "triple point" when ice (solid), water (liquid), and vapor (gas) coexist in equilibrium. This point is the freezing point of water and is set by international agreement to equal 273.16 kelvin (0 degrees Celsius; 32 degrees Fahrenheit).

triplen harmonics - The name for the odd multiples of the third harmonic (3rd, 9th, 15th, 21st, etc.), i.e., every third odd harmonic. An order of harmonic that is a multiple of three. Common to 3-phase AC voltage generators.

triplet - A group of three notes having the time value of two notes of the same kind. Also called tercet.

Trombonga - Invented by seven-time Grammy winner Eddie Palmieri this trombone-fueled music style combines Afro-Caribbean beats with frantic jazz piano improvisation.

TRPA1 (transient receptor potential #A1) - (pronounced "trip-ay-one") Protein that translates sound waves into nerve impulses. Discovered in 2004 by a research team lead by neurobiologist David Corey of Harvard Medical School (the team consisted of researchers at U.Va., Northwestern University, Duke University, Harvard Medical School and the National Institutes of Health.). This is the long sought missing link in the ear's conversion of sound waves into electrical signals that the brain can recognize as distinct sounds. The protein is located in a tiny channel located at the tips of the inner ear's hair cells (also found in mice, fish and fruit flies).

TRRS connector - tip, ring, ring, sleeve is a common family of connector typically used for analog signals including audio. It is cylindrical in shape, with four contacts.

TRS connector - tip, ring, sleeve is a common family of connector typically used for analog signals including audio. It is cylindrical in shape, with three contacts.

true response graphic equalizer - A graphic equalizer whose output characteristics perfectly match the position of the front-panel slide controls. Contrast with proportional-Q and constant-Q designs.

truncate - To eliminate without round-off some low-order bits, often after performing an arithmetic computation.

TS connector - tip, sleeve is a common family of connector typically used for analog signals including audio. It is cylindrical in shape, with two contacts.

TT (tiny telephone) - Shorter and thinner than 1/4" TRS jacks, it is the term for the small patch cables originally used in telephone patchbays. Also called bantam jacks.

TTL (transistor transistor logic) - The workhorse digital logic integrated circuit family introduced as a standard product line in 1964.

TTM (turntablist transcription methodology) - A system of music notation developed by John Carluccio in 1997, for turntablism (see below). His system uses a modified musical staff with the vertical axis representing the direction of rotation of the record and the horizontal axis representing time.

Turntable U - Online popular and successful DJ school.

turntablism - A form of music founded by turntablists, that is already mainstream enough that the Berklee College of Music publishing arm, Berklee Press has issued books and vinyl records for this music form.

turntablist - A performing artist who uses two or more turntables as music sources from which he/she creates original results by quickly cutting and mixing the sounds of each, using specially designed performance mixers such as Rane's TTM 56.

TVS (transient voltage suppressor) - Originally MOV (metal oxide varistor) (GE trademark). Semiconductor devices designed to provide protection against voltage and current transients.

tweeter High-frequency loudspeaker.

TwinVQ (transform-domain weighted interleave vector quantization) - Name of a music compression technology developed at the NTT Human Interface Laboratories in Japan. A transform coding method like MP3, AAC or AC-3.

twisted-pair - Standard two-conductor copper cable, with insulation extruded over each conductor and twisted together. Usually operated as a balanced line connection. May be shielded or not.

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