Glossary of Home Theater Terms P-T


Main Glossary A-E F-J K-O P Q R S T U-Z

Select the first letter of the word from the list above to jump to appropriate section of the glossary.

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- P -

PAC

Perceptual Audio Encoder. A 5.1-channel surround-sound system developed by Bell Laboratories, and designed originally to compete in the broadcast realm with Europe's Musicam and Dolby's AC-3 systems.
 
PASC

Precision Adaptive Sub-Band Coding. The low-bit-rate, digital data-reduction coding process used in the Philips-developed DCC tape-recording system. See also Data reduction.
 
PCM

Pulse Code Modulation. The standard playback or recording system employed by the CD and most professional-grade digital recorders, including DAT. In contrast to digital data-reduction systems, PCM recording systems allow 100 percent of the material recorded to be played back.
 
PIP

Picture in Picture. A TV set that can place a smaller picture derived from a different signal within the larger main picture. In most sets, this requires the addition of another tuner, usually from a VCR.
 
P-mount cartridge

A plug-in phono cartridge originally designed by Technics but now used by a number of other companies. Its main advantage is ease of alignment.
 
PWM

Pulse Width Modulation. See Bitstream processing.
 
Pan and Scan

A method of transferring wide-screen films to smaller-ratio TV screens, whereby the full image is not shown at all times. For example, an original wide-screen shot might show two people talking to each other; in a pan-and-scan version, each person might be shown individually, with the camera moving (panning) between them as they speak. See also Letterboxing.
 
Pan potting

The individual level controls for each channel in a multitrack recording mixer are called pan pots. Pan potting is used to adjust each of those tracks for acceptable balance.
 
Passive crossover

A nonpowered electrical network that divides the frequency constituents of an audio signal (bass, midrange, and treble) after it has been amplified and then routes them to the various drivers in a speaker system. In most situations, it is enclosed within the same box as the speaker drivers.
 
Passive radiator

Also called drone cone. A nonpowered bass driver. Passive-radiator drivers are often employed and behave as independent bass speakers below the resonance of the active drivers. See also Bass reflex.
 
Perceptual coding

See
Masking
 
Phantom-center channel

The image that is formed between two front-center speakers when they combine their identical outputs. Such an image cannot usually be properly formed unless the listener is sitting in the "sweet spot:' See also Dolby Surround; Matrixing
 
Phase distortion

Also called phase shift and sometimes group delay, it results when one part of the frequency spectrum is delayed more than another. Phase shifts can cause test waveforms viewed on an oscilloscope to distort but must be fairly extreme if they are to be audible when listening to music under normal home-playback conditions, at least with loudspeakers.
 
Phasiness

An overly spacious characteristic that may be imparted to solo instruments or singers if they are improperly recorded. To get an idea of extreme phasiness, temporarily reverse the leads of one of your loudspeakers and notice how any centralized images become quite diffuse (there may also be a loss in bass power, but that is not what we are dealing with here). On some recordings, the left and right channels will appear to be in phase and solidly imaged, while the center will appear to be slightly out of phase and ill-defined. See also Spaced-array microphones; Focus; Imaging.
 
Pinch roller

See
Capstan.
 
Pink noise

Random noise (hiss) that has equal energy in each octave.
 
Pinna

The projected, curved parts of the outer ear that contour the frequency response and phase characteristics of the sounds going to the inner ear, allowing the brain to determine from which direction they emanate.
 
Planar-magnetic loudspeaker

A flat, panel-type speaker that radiates sound from both front and back. This design looks similar to some electrostatic designs but uses a widely dispersed variant of the magnet-and-coil system found in typical dynamic models. Because of this, there is less electrical load on the amplifier, and thus these speakers are less likely to cause erratic amplifier behavior.
 
Polar response

A plot of output amplitude of a single frequency vs. the angle off-axis. In other words, the variation in radiated or received energy with the angle relative to the axis of the radiator or receiver. The measurement can be used with either speakers or microphones. See also Radiation pattern.
 
Power response

In loudspeakers, the integrated output in all directions. In most rooms, the overall level of the power response swamps the tonal effects of the direct signal. See also Room response.
 
Preamplifier

Strictly speaking, the stage of an audio circuit that amplifies the very small output of a phonograph cartridge, allowing it to be successfully further amplified by a power amplifier. The term is often applied to the entire control section of a receiver, integrated amplifier, or stand-alone "preamplifier." Some stand-alone preamps also contain surround-sound processing circuitry and A/V switching.
 
Precedence effect

When identical sounds come from two different speaker systems, if the distance is great enough, the ear tends to attribute all the sound to the near one. This phenomenon is one reason that the surround-channel sound in a DPL system is delayed relative to the main channels. Similar to the Franssen effect, where percussive bass signals have their localization determined by the position of higher-frequency drivers in a speaker system. Also known as the Haas effect. See also Direct field; Power response.
 
Pre-emphasis

A deliberate change in the frequency response of a recording system for the purpose of reducing distortion or improving the signal-to-noise ratio.
 
Pro Logic

The proprietary system of center-channel steering licensed by Dolby Corporation. Its function is to "steer" center-channel information to a center speaker in Dolby-encoded audio programs. On nonencoded material, the steering may still offer an improvement over standard two-front-channel playback. See also Phantom-center channel.
 
Progressive scan

The process of imaging a picture by having the numerous scan lines that form it laid down continuously, eliminating artifacts that result from interlacing. Commonly used in computer monitors and high-definition television sets. See also Interlaced scan
 
Projection television set

A TV that employs either three CRT tubes or an LCD arrangement to project an image on a special screen. The most common are rear-projection models, which use lenses and mirrors within a large box to project the image to the inside of a translucent screen, the outside of which faces the viewer. Less common are front-projection models, which mount the projector across the room from a conventional screen.
 
Psychoacoustics

The study of the relationship between human hearing perception and stimulus; in other words, the study of how we hear.
 
Punch

A strictly subjective term that refers to the ability of a recording to deliver dynamic snap and impact.
 
Push-pull woofer system

A bass loudspeaker that makes use of two woofer drivers mounted in the same cabinet but facing in opposite directions. Wired out of phase from each other, this mounting technique allows the two to move in and out together, reducing even-order distortion products. The system is used in both full-range systems and subwoofers.
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- Q -

Q

In loudspeakers, a measure of directionality. At low frequencies, the Q will always be low. At higher frequencies, it gets larger, depending on the size of the drivers involved. Thus, Q is a measurement of frequency-dependent radiation pattern and polar characteristics. Q is also a measurement of the slope of any peaks in loudspeaker, equalizer, or microphone frequency-response curves.
 
Quadraphonic sound

The term used to describe any of several surround-sound systems developed in the 1970s. These days, the term surround sound is more popular.
 
Quantization

In a digital-audio signal, the number of possible values available to represent various levels of amplitude.
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- R -

 
RCA plug

The standard audio line level and video connecting plug found on amateur-grade equipment in the USA.
 
RF

Radio Frequency. A signal used to transmit audio and video information through the air or through cable. While virtually all receiver-equipped TV sets and VCRs can receive RF signals, all VCRs and some laser-video players can also transmit them through a cable to a TV set. The latter function results in picture and sound that is inferior to what is possible with direct video and audio hookups.
 
RFI

Radio Frequency Interference.
 
RGB input

Red/Green/Blue input. The separate-color professional-grade interface that some TV monitors employ to receive data-grade video. The result is a picture much improved over that delivered by regular direct-video or even S-Video inputs.
 
RIAA

Recording Industry Association of America. This group develops standards for recordings in this country. The RIAA "curve" is a record/playback compensation curve applied to LP records that allows them to have flat response with minimum distortion.
 
RMS

Root Mean Square. A common measurement of average power output in audio amplifiers.
 
RPM

Revolutions per minute.
 
RTA

See
Real-time analyzer.
 
Radiation pattern (R-P)

The polar response characteristics of a loudspeaker system at all frequencies. Along with power response, the R-P is what mainly determines the subjective impression of a loudspeaker. In a microphone, this might be called its radiation-pickup pattern. See also Polar response; Dispersion
 
Random noise

Any kind of hiss-like noise produced by special noise generators. Similar noise can also be heard when a TV or radio tuner is tuned to a channel that has no station transmitting. See also Pink noise; White noise.
 
Reactance

In passive or active AC circuits, a form of frequency-dependent resistance produced by an inductor. An inductor will let DC current pass through unaltered and will attenuate higher frequencies, depending on its reactance.
 
Real-time analyzer (RTA)

A device for measuring the amplitude of specific signals in the audio bandwidth. An RTA presents a continual readout of the signal amplitude in evenly divided spectral bands, with either music or test signals as a source. See also Frequency response
 
Real-time counter

On VCRs, DCC decks, and MiniDisc recorders, a device that measures play and record time in actual seconds, minutes, and hours instead of arbitrary numbers
 
Receiver

In audio, a component combining a tuner, preamplifier, and amplifier into one chassis. Most modern audio receivers also contain A/V switching abilities and surround-sound circuitry. In video, any component that can receive antenna or cable video signals.
 
Resistance

Commonly, the non-frequency-dependent resistance of current flow within an electrical circuit. See also Impedance.
 
Resonance

The tendency for a mechanical or electrical system to vibrate at specific frequencies. The most common problems with resonances in modern audio hardware involve loudspeaker systems and microphones.
 
Reverberant field

A technical term that defines the sound field that exists when the reflected sound in a listening or monitoring room predominates over the direct sound from the source (be it a loudspeaker or performers). Obviously, it is strongly effected by room layout, reflectivity, and size. See also Direct field.
 
Reverberant sound (reverb)

The amount of ambience and hall reflections captured during the recording process. Reverb can be recorded naturally, but many engineers add it synthetically to compensate for deficiencies in the recording environment.
 
Reverberation

The multiple sound reflections that result when sound is produced in an enclosed space. See also Ambience; Early reflections; Late reflections
 
Ribbon speaker

A design that uses a long, very thin narrow metal conductor suspended in a magnetic field. Ribbons are usually employed as tweeters or tweeter-midranges, because their design does not allow for good performance in the bass range. Ribbons usually have good horizontal and limited vertical dispersion. See also Line-source loudspeaker
 
Rolloff

Commonly, a gradual reduction of audio output above and below specific frequencies. Usually applied to loudspeaker or microphone performance, it can also be used to describe the sound of recordings at their frequency extremes.
 
Room response

The power response of a loudspeaker as measured in a given room. The measurement includes both the direct signal and the reflections from the room boundaries, minus the sound absorbed by the furnishings. See also Power response.
 
Rumble

The low-frequency mechanical noise that appears on some recordings, which can be caused by any number of things, including mechanical or stage noise at the recording source. In the old days, rumble was also caused by LP turntables feeding through to the speakers or from the sound made by the cutting lathe that made the record master.
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- S -

SAP

Second Audio Program. In video systems, the SAP channel can be used to provide an alternate soundtrack-especially helpful when there is a need to broadcast dialogue in a language different from what is being delivered by the main channels.
 
S-VHS

See
Super-VHS.
 
S-connector

The video hookup employed by S-VHS, ED Beta, and some laser-video players to keep the Y (luminance) and C (chrominance) signals separate. This hookup is sometimes called a Y/C connection. See also Super-VHS.
 
SLP

In VCR parlance, Super Long Play, the slowest play and record speed. Sometimes called EP, or Extended Play.
 
SMPTE

Society of Motion Picture and Television Engineers.
 
S/N ratio

See
Signal-to-noise ratio.
 
SP

In VCR parlance, Standard Play, the fastest play and record speed.
 
SPL

Sound-Pressure Level. See also dB.
 
Sampling rate

In digital systems, the rate in Hz at which the circuitry determines the signal amplitude. For CDs, this is 44.1 kHz; for RDAT recorders, it can be either 48, 44.1, or 32 kHz.
 
Saturation

A magnetic-recording term used to describe a condition whereby recording tape or tape heads are carrying all the signals that they can handle. Any additional input results in no additional storage or recording output levels.
 
Scan-velocity modulation

A feature on some TV sets that adjusts the rate of horizontal movement of the electron beam as it scans the picture. This results in a sharper picture
 
Sensitivity

A standardized speaker measurement that determines how loud a system will sound under controlled conditions. The standard procedure agreed upon by the industry is output, in dB at 1 meter with 2.83 volts applied, which will amount to 1 watt at 8 ohms (2 watts at 4 ohms). while sensitivity has little bearing on overall sound quality, it will be a factor in determining the required amplifier power.
 
Shadow mask

On a direct-view television picture tube, this is the perforated screen that is bonded behind the front glass surface, which limits color distortion (or blooming) and also improves contrast. See also CRT.
 
Signal-to-noise ratio (S/N ratio)

Often arbitrarily assigned, the S/N ratio should be the difference, in dB, between the noise floor of a playback component or sound recording and the loudest level it can achieve with inaudible distortion. The measurement is sometimes weighted as to audibility, because the ear is more sensitive to some frequencies than others. The most generous scale is dBA (A-weighted). In any case, the larger the S/N number, the better. See also dB; Noise floor.
 
Slew rate

See
TIM.
 
Slope

In audio, the rate of change that a frequency-response curve displays, normally stated in dB per octave. Among other things, slope can relate to crossover-point attenuation rates, woofer low-end rolloff rates, or equalizer control functions.
 
Software

Another term for audio or video recordings.
 
Solid state

Electronic circuits whose active elements are transistors and integrated circuits, rather than tubes.
 
Sound field

In audio-video circles, this term relates to the "totality" of the sound presented by the sound-system-recording combination. In audio-only recordings it will involve the direct sound of the players, the sense of envelopment, the reverberation and ambience of the studio or hall-and even the interaction of the recording with the playback system and its environment. In A/V performance, it will involve how well the sound of the system interacts with the material on the TV screen. While the quality of the source material is critical, the sound field will be greatly influenced by the quality of the playback system, its arrangement within the listening-viewing room, and whether it incorporates surround-sound hardware.
 
Sound power

The amount of energy radiated by an audio source, measured in joules per second, or watts. Its most common use is with loudspeakers, where power response is measured by how sound power varies with frequency.
 
Sound stage

In audio or video sound, this often vaguely defined term refers mostly to the left-right spread of the sound between the speakers in a playback system. It can also be used to define a sense of front-to-back depth. While the sound system layout can be critical, recording quality is also of great importance in influencing the sound stage.
 
Source

The signal that is played through an audio or video system. It may be something received over an antenna or cable system or be from an installed component like a VCR, videodisc player, CD player, or audiocassette deck.
 
Spaced-array microphones

A technique whereby the microphones recording a stereo program are placed some distance apart and in front of the ensemble or individual. This allows timing, as well as intensity, cues to be reproduced. Some critics think the technique results in a sense of direct-sound phasiness or diffuseness in the center image. Adding an additional center microphone may alleviate some of these negative characteristics. See also Coincident-microphone recording; Comb filtering; Phasiness; Monophonic.
 
Spatial averaging

An energy average over a given space around a loudspeaker system. Spatial averaging measures the effects of the speaker's radiation pattern but may include only small segments of the front hemisphere or sphere around a speaker. Its advantage as a measurement technique is that it limits the effects of acoustical interference while taking into account the amplitude irregularities caused by resonances within the speaker itself. See also Spectral averaging; Power response.
 
Speaker level

The moderate-voltage outputs of an amplifier or amplifier section of a receiver or integrated amplifier. While these are mainly designed to power loudspeaker systems, some subwoofers have speaker-level inputs to their built-in active or passive crossover networks. See also Line level.
 
Spectral averaging

An energy average over a given band of frequencies produced by a loudspeaker system. Thus, it will measure frequency response at specific, fixed angles around a system, as well as the power response. See also Spatial averaging.
 
Spectral balance

Relates to the ability of a speaker system to integrate its direct and reflected sound so that it sounds balanced, smooth, and transparent in a typical listening room.
 
Square wave

A waveform consisting of a fundamental and all the odd-numbered harmonics it produces. Because it consists of energy to at least the 20th harmonic, it can be used for frequency-response evaluation with electronic components. Any amplifier that can reproduce an exact 1-kHz fundamental square wave cleanly will be clean to 20 kHz.
 
Standing waves

These are irregularities (quite audible and unwanted in the bass range) that result when sounds reflected back and forth between the walls of a room interact with each other and with the direct sounds from the speaker systems that produced them to form alternate reinforcements (peaks) and nulls. The effect is dependent upon the size and shape of the room and the listening position and, to a smaller degree, on the positioning of the speakers. Standing waves can be detrimental to sound reproduction at lower frequencies in small and/or badly proportioned rooms, where their effects are often extreme.
 
StarSight

A proprietary subscription-activated menu system built into some TV sets and VCRs to aid in program selection and recording.
 
Steering

Most notably used in Dolby Pro Logic systems, the electronic manipulation of recorded audio signals from two-channel sources allowing encoded center-channel material that would ordinarily only be vaguely imaged to be positively routed to a center speaker and surround material to be similarly routed to the surround speakers. The goal of steering up front is to simulate three discrete-channel sources, with surround steering normally simulating a broad sense of space around the viewer.
 
Stereo

From the Greek for "solid"' In audio, it ordinarily refers to a recorded program that uses two speakers in front to recreate the left-right sound-stage image of a live performance. If done right, stereophonic reproduction can also lend a certain degree of depth to the sound. Surround- and ambient-effect sound systems, making use of more than the standard two "front" speakers, are also an advanced form of stereo. The latest incarnation for home audio-video is Dolby AC-3.
 
Stridency

A nontechnical term that usually refers to violin sound that is too close up, edgy, bright-sounding, or metallic. Many recording engineers get in close to those instruments with accent microphones, in order to capture their detail and allow them to compete with the much-louder brass section of the orchestra. However, even minimalist recording techniques may result in stridency, because they are often produced when the hall is nearly empty and there is no audience to absorb some of the excess high-frequency energy. See also Minimalist technique.
 
Stylus

The external moving part of a phonograph cartridge. Usually, it will included a jeweled tip (nearly always a diamond) and a cantilever or shank connecting the tip to the magnets or coils within the cartridge body.
 
Sublective testing

Judging audio or video gear by listening or viewing without using any measurement instruments. while some people can be quite sensitive to differences in audio or video quality, many are misled either by environmental factors or personal predispositions. See also Objective testing.
 
Subsonic filter

See
Infrasonic filter.
 
Subwoofer

An electronic or mechanical device that extends the deep-bass response of an audio system. The most common are add-on, large, conventional woofers, which must be careflilly aligned to work properly. Electronic-type "subwoofers" are actually equalizers that are dedicated to standard woofer systems and electrically boost the low-bass range to achieve smooth, flat low-bass response. Many add-on subwoofers incorporate electronic equalizers to flatten out the bottom of their ranges. See also Equalizer; Woofer.
 
Suckout

Bass-range reflections from nearby floor or wall boundaries that partially null the primary signal coming from the speaker itself. The suckout phenomenon differs from standing waves or higher-frequency reflections in that relocating the listening position or padding the walls is not a cure. Suckout involves only the bass, particularly the midbass (although it can also cause interactions in the low bass between two widely spaced woofer systems), and requires very careful speaker placement to correct. See also Standing waves.
 
SuperVHS

Also called S-VHS; the high-band, sharper-picture upgrade to standard VHS.
 
Supertweeter

A tweeter designed to reproduce the very highest frequencies above the 2-15 kHz range normally handled well by a good standard tweeter. Supertweeters are usually found in four- or five-way systems and are sometimes placed on the back of a cabinet, facing the wall behind the system. Note that a decent conventional tweeter should be capable of doing everything important that a supertweeter should do, because the highest frequency most people can hear distinctly (particularly if they are past the teen years) is about 15 kHz, and most music and film sound does not have significant energy past 12 to 13 kHz. The only way a supertweeter would offer an advantage would be if its radiating-surface diameter was very small-say one-half inch or less. This would result in improved dispersion above 10 kHz, compared with that of a typical 1-inch dome tweeter. Some supertweeters are said to have strong response to well above 20 kHz, but CDs, videodiscs, and videotapes do not reproduce that range, and nobody can hear up that high, anyway.
 
Surround sound

The matrixed, synthesized or discrete rear-, side-, or center-channel outputs that are integrated with the main channels of a stereophonic audio or audio-video system to enhance realism and ambience. Most modern versions have separate amplification for those channels. See also Dolby Surround; Ambisonic; Hafler circuit; Dolby Digital; DTS; Center Channel; DSP; Extraction processors; Synthesizing processors.
 
Surround speakers

The usually small speakers that are placed toward the sides or toward the rear in a surround-sound playback system and handle the decoded, extracted, or synthesized ambience signals. Some manufacturers refer to them as "rear-channel" speakers, a misnomer.
 
Sweet spot

The so-called "best" listening (or viewing) position for enjoying an audio (or audio-video) system. Usually, it is centered between the main speakers and about as far from their connecting axis as they are from each other. Sweet-spot listening is mandatory for good imaging with systems that employ only two speakers up front. See also Center channel
 
Synthesizing processors

These are surround-sound devices for home use that add their own preprogrammed hall ambience and reverberation to the sound of a recording. This "overlay" of ambience can greatly benefit some recordings, particularly those that are fairly dry sounding. However, the effect can muddy the sound of recordings that have a fairly large amount of reverberation to begin with. Recording engineers often employ synthesizing devices to add ambience to the recordings themselves. See also Ambience; Surround sound; Extraction processors.
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- T -

THD

See
Harmonic distortion.
 
THX

A LucasFilm Corporation performance certification program for A/V software and hardware, particularly dealing with Dolby Pro Logic and Dolby Digital behavior but also involving TV monitor and laser-video picture and sound quality. See also Dolby Pro Logic; Dolby Digital.
 
TIM

Transient Intermodulation Distortion. The intermodulation distortion caused by time lags in amplifiers operating at very high frequencies that have very high levels of negative feedback. Also called slew-induced distortion; an amplifier that is relatively immune to it is said to have a high slew rate. TIM can be controlled by an input that is rolled off above the audible frequencies so that signals too "fast" for feedback to handle will be nonexistent. See also Intermodulation distortion; Negative feedback.
 
Tape loop

On most preamplifiers, integrated amplifiers, and receivers, the switch-operated hookup that allows a tape deck to be properly integrated into the system. A tape loop will have an input for tape playback and an output for tape recording. See also EPL; Tape monitor.
 
Tape monitor

The switch that inserts a tape loop into a circuit. With some recorders, this allows you to do an A/B comparison between the source material and the recording as it is being made.
 
Timbre

The quality given to a sound, particularly a musical sound, by its overtones. In audio, a popular term describing the basic tonal quality of a sound system, particularly the speakers.
 
They-are-here sound

A recording technique that tries to simulate the effect of a performer or performers on a recording actually being in the listening room, rather than having the listener subjectively transported to the hall itself. This is only viable when small-scale sound is being recorded, particularly that of solo instruments with limited volume capabilities, such as guitar, harp, and violin-or maybe a string quartet. In many cases, the effect is probably the accidental result of the engineer and/or performer simply trying to reproduce a small-hall effect. See also You-are-there sound.
 
Three-way speaker

A loudspeaker system that uses separate drivers for the high frequencies, midrange, and bass. Certain designs may have more than three speaker drivers, but because some are paired together to handle the same frequencies, they will still be three-way designs. See also Two-way speaker.
 
Time-base corrector

A circuit found in all analog LV players (advanced versions employ digital circuitry) and some VCRs that electrically corrects for small mechanical speed errors.
 
Time shifting

Setting a VCR to record a program for later viewing.
 
Tonality

A subjective term that refers to the clarity and accuracy of the sound of an instrument or group of instruments. It can also refer to those qualities in vocal reproduction.
 
Tone arm

The mechanism on an LP record player that holds the cartridge in proper position over the record.
 
Tone burst

A momentary sine-wave signal that is used to test the transient response of an audio component. While a tone burst can theoretically measure the tendency of a component, particularly a loudspeaker, to continue to oscillate after the input signal is cut off, a proper frequency-response sweep will do the same thing, because these resonances will show up as peaks or dips in the sweep curve. See also Frequency response; Transient response
 
Tone control

The control on a preamplifier, integrated amplifier, or receiver that boosts or cuts certain segments of the audible bandwidth. Bass and treble controls are the most common versions, but some units have midrange controls also. See also Equalizer
 
Tracking

The ability of a CD player, LV player, VCR, or LP phonograph stylus to follow the mechanical or electrical pattern on a tape or disc.
 
Tracking control

On a videotape recorder, the control that adjusts the "head-switching" network contained within the deck's electronic circuitry. Many modern decks have automatic tracking controls.
 
Transient response

The ability of an audio component to quickly respond to the signal being fed to it. Transient response is more critical in mechanical components like speakers, phono cartridges, and microphones. See also Tone burst.
 
Transparency

In audiophile circles, the ability of a sound system or recording to achieve a realistic sense of imaging, space, and clarity. Most commonly used to describe the capabilities of speaker systems.
 
Transponder

Used in video satellites to receive program material from ground-station uplinks and then retransmit it to properly aimed dish receivers back on the ground.
 
Transport

The mechanical part of an LP turntable, audio tape deck, CD player, LV player, or VCR that moves the disc or tape so that the signal can be reproduced.
 
Treble

The high-frequency range of the audible spectrum, running from 3 or 4 kHz on up to 15 or 20 kHz (less than three octaves).
 
Tuner

The component that receives the RF signals (radio, video, satellite) from an antenna or cable system. Audio tuners are sometimes stand-alone units but are usually configured as part of an audio or audio-video receiver. Video tuners are usually included as part of a TV set or VCR. A satellite receiver is a tuner designed to receive either analog or digital satellite-transmitted signals that are received by a dish antenna.
 
Tweak

To adjust an audio or video component so that it works at its very best. Also, a slang term for an audio extremist who dwells on the more mythical aspects of audio in preference to more rational beliefs that are substantiated by objective testing procedures.
 
Tweeter

The individual speaker unit (driver) designed to handle the treble range. See also Treble.
 
Two-way speaker

A speaker system that uses separate drivers for the high and low frequencies; the midrange frequencies are split between them. Two-way systems usually suffer from midrange dispersion problems, because the woofer, which must be robust enough to do decent work down low, is usually not small enough in diameter. Some two-way systems employ a nonpowered passive radiator to augment the deep bass. See also Three-way speaker; Passive radiator.
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