Guide to Troubleshooting Consumer Electronics Audio Circuits: Glossary

Amplitude --- The height of a waveform, either positive or negative.

Analog Filter---A filter system in the CD player that reduces and cancels out noise.

Acoustic Suspension---(AS) or air suspension speakers with low frequency reproduction enclosed in a solid box to produce natural, low-distortion bass output.

Air Suspension---Another name for an acoustic-suspension speaker.

Ambience Simulation---Refers to the sound environment of a given space in a room.

Amp---Abbreviation for amplifier.

ANRS --- A noise-reduction system operating similar to the Dolby systems.

Auto Eject --- The tape is automatically ejected at the end of the playing time in the cassette player.

Automatic Shutoff --- A switching arrangement that automatically shuts off a device, product or circuit.

Auto Record Level --- The automatic control of the recording level.

Auto Reverse The cassette player automatically reverses direction to play the other side of the tape in the auto tape player.

Azimuth --- The angle of the tape head. A low high frequency response is noted with improper tape head alignment.

Baffle---The board on which the speakers are mounted.

Balance --- A balance control equalizes the left and right channel audio output.

Bass Reflex---To improve the bass response, the sound waves are vented through a tuned vent or port.

Bias---A high-frequency signal switched to the tape head winding to prevent low distortion and noise on the tape during recording.

Block Diagram---A boxed diagram showing the various electronic circuits of a cassette and CD player, radio and amplifier.

Booster Amplifier---A separate amplifier connected between the main unit and the various speakers in the auto hi-fi system.

Bridging--- Combining both stereo speaker outputs to produce a monaural signal to almost double the normal car stereo amplifier.

Capstan---The shaft that rotates the tape at constant speed past the tape heads in a cassette player or VCR.

Cartridge---A component that holds the stylus or needle in the record player. The cartridge develops the voltage from movement on the record to the audio amplifier.

Cassette Radio---A combination of an AM/FM tuner, amplifier and cassette player in one cabinet.

CH The abbreviation for channel. The stereo amplifier has a right and left channel output.

Chip Devices---Many different chip SMD (surface-mounted devices) such as thick- film resistors, chip ICs, chip transistors, multi layer ceramic chip capacitors, and mini-mould chip diodes are found in today’s electronic chassis.

Clipping ---Clipping can occur if a stage is distorted or with too much volume is applied in the amplifier. Clipping can be seen on the oscilloscope.

Coaxial Speaker---A speaker with two speakers mounted in one frame. Usually, the tweeter is mounted ahead of the woofer speaker in the car radio system.

Compact Disc (CD) --- The compact disc player plays a small disc of digitally encoded music. Mount the rainbow-like surface on the disc holder. Place the disc label upwards.

CPU---A computer-type processor (central processing unit), used in micro, master or mechanism circuits of electronic products.

Crossover---A filter network that applies certain audio frequencies to each speaker. The highs to the tweeter and the low frequencies to the woofer speakers.

Crosstalk ---Crosstalk is leakage of one channel into the other caused by improper tape head alignment.

D/A Converter---The stage that separates the digital from the analog or audio signal.

DBX---Abbreviation of decibels in a noise-reduction system in which the program is compressed before being recorded and expanded in playback.

DC Direct current found in batteries or the low-voltage power supplies.

Decibel (dB)---A measure of gain; the ratio of output power or voltage with respect to the input.

Digital---Information expressed in binary terms.

Digital Filter---A low-pass filtering network.

Direct-Access Time --- A control feature that lets you simply touch a place in the volume scale to set it.

Dispersion --- The angle in which the speaker radiates the sound.

Distortion --- Distortion might appear as harmonics or multiples of the input frequency. Clipping of the audio waveform is a form of distortion. The deformation of an audio signal waveform.

DNR (Dynamic noise reduction) --- A noise-reduction system that reduces the high frequencies when the signal is at a low level.

Dolby Noise Reduction --- A type of noise reduction that by increasing the high- frequency sounds during recording and decreasing them during playback, returns the audio signal to the original level and eliminates hiss tape and other recorded noises.

Driver in a speaker system, each separate speaker might be called a driver.

Dual Capstan---Dual capstans and flywheels are found in auto-reverse cassette players.

Dynamic---A dynamic speaker has a voice coil that carries the signal current in a pm magnetic field. A pair of headphones operate in the same manner.

Dynamic Range---The ratio between the maximum signal level and minimum level expressed in decibels (dB).

Efficiency---A percentage of electrical input power to a given speaker that is connected to audio energy.

Electrostatic---A electrostatic speaker, headphone, or meter that uses a thin diaphragm having voltage applied to it. The electrostatic field is created by the signal voltage, which moves the diaphragm to create sound.

Equalization (EQ)---Alteration of the frequency response so that the frequency balance of the output equals the frequency balance of the input. Equalization is also used to correct response deficiencies in speakers and tape player circuits.

Equalizer---A device to change the volume of certain frequency in relation to the rest of the frequency range.

Erase Head The erase head with applied voltage or current removes the previous recording on the tape. The erase head is mounted ahead of the play/record tape heads.

Fader --- A control in auto radios or cassette players used to control music between front and rear speakers.

Fast Forward (FF) ---The motor or the large idler pulley is engaged .to speed up the forward rotation of tape in the cassette player or VCR.

Filter---A circuit that attenuates certain frequencies, but not others. The large capacitor in the low voltage power supply might be called a filter capacitor.

Flutter---A change in fast speed of a tape transport. A low-speed change might be called wow.

Folded Horn Speaker---A system that forces the sound of the driver to take a difficult path to the listener.

Four Track Four separate parallel magnetic tracks can be recorded on regular tape width found in quad-tape players.

Frequency Response---The range of frequencies the amplifier can pass to the listener. The frequency response of a given amplifier might be 20 Hz to 20 kHz. The average listener can hear from 35 to 1 5-kHz.

Full-Range-Speaker---A speaker system with only one driver that reproduces the normal frequency range.

Gain---The amplification of a given signal in decibels (dB).

Gain Control---A control to adjust the volume or boost amount of signal.

Gap The distance between the pole pieces of a tape head. A gap with excessive tape oxide might result in a weak and distorted sound.

Graphic Equalizer---An equalizer with a series of sliders that provides a graphic display.

Ground---A common point of zero return for components within electronic circuits. The common ground can be a metal chassis in the amplifier or receiver.

Harmonics---A series of multiples of the fundamental frequency.

Harmonic Distortion---Harmonics is indicated by the amount of harmonic distortion. A tape player should have less than 1% distortion.

Head---A magnetic monaural or stereo tape head that picks up the signal from the moving magnetic tape.

Herb (Hz) --- The unit of frequency in cycles per second (cps).

Hiss---The annoying background noise in tape and cassette players. Defective transistors and IC components can produce a hiss or frying sound in the speakers.

Hum --- Hum noise originates from the power line. Pickup hum might result in poor solder input or ground terminals of audio components.

Idler---A wheel found in the cassette player to determine the speed of the capstan / flywheel.

IMD (inter modulation distortion) Distortion at frequencies that are the sum and differences of multiples of the input frequency.

Impedance --- The symbol is Z and the unit in ohms. The impedance of a speaker might be 4, 8, 10, 20, and 32 ohms. The impedance of a yaggi antenna is 300 ohms.

Infinite Baffle---A completely sealed box that encloses speakers.

Integrated Amp--- single component containing all amplifier components in one envelope.

Integrated Circuit (IC)---A single component with many internal parts. ICs are used throughout the stereo amplifier in the TV set.

Inter modulation Distortion (IMD)---The presence of unwanted frequencies that are the sum and differences of test signals.

IPS (inches per second)---The measurement of tape speed.

Jack---A female part of a plug and receptacle.

KHz (kilohertz; 1000 Hz or 1000 cycles per second).

LED (light emitting diodes)---These are found as optical readouts and displays or indicators within the electronic product.

Level---The strength of a signal. The alignment of a tape head.

Line --- Line input and output jacks are found in the amplifier, cassette deck and CD players.

Loading Motor ---The motor in the CD, VCR, camcorder or cassette player

Loading Way ---The tray that holds the compact disc during loading of the CD player.

Long Play (LP) --- A speed of the VCR that provides four hours of recording on a 120- minute VHS cassette.

Loudness The volume of sound. Loudness is controlled by the volume control.

Loudness Compensation --- A switch that boosts a low-level to compensate for the natural loss of sound at the human ear.

LSI (Large scale integration)---Many electronic components built inside one large chip with many terminals. ICs, processors and CPUs might be called LSI components.

Magnetic Metal Attraction---The magnetic pickup, tape head, VOM or VTVM have magnetic components.

Microprocessor---A large IC chip with many functions and terminals.

Megahertz --- 1 MHz equals 1,000 kHz or one million cycles per second.

Metal Tape --- The high-frequency response and maximum output level are greatly improved with metal tape.

Monitor---The scope and external audio speaker can monitor the intermittent audio circuit. To compare signals.

Monophonic One audio channel. Stereo sound has a right and left audio channel. MOSFET Metal-oxide semiconductor field-effect transistor.

Multiplex --- A demodulator or decoder circuit that converts a single carrier signal into two audio stereo channels.

Mute Switch---A switch that turns off the sound in the TV, CD player or large receiver.

Noise --- Any unwanted signal found in the reproduction of sound.

Noise suppressor --- A filter to reduce background noise.

NR --- Abbreviation for noise reduction.

Output Power --- The output power of an amplifier, rated in watts.

Oxide --- The magnetic coating compound on the magnetic tape that rubs off and becomes packed on the cassette tape head.

Passive Radiator---A second woofer cone that is added without a voice coil.

Pause Control The pause control stops the tape movement from the magnetic tape head in the cassette player or VCR.

PBX --- The noise-reduction system in which the program is compressed before being recorded and expanded in playback.

Peak --- The level of power or signal.

Phase---Sound waves in sync with one another that connect the speakers in phase with one other.

Piezoelectric Speaker A ceramic element that expands or bends under applied signal voltage in a speaker.

Playback Head --- The only head found in a playback only cassette player. The playback head might also be used as a P/R head in the cassette player.

PLL (phase-locked-loop)---A variable control oscillator (VCO) tied to the digital control processor.

Port --- An opening in a speaker enclosure for back-bass radiation. Power The output power of an amplifier is given in watts.

Preamplifier---The preamp is the first stage in the amplifier and is connected to the tape head winding within the cassette player.

Rated Power Bandwidth---The frequency range over which the amplifier supplies a certain minimum power factor (20 to 20,000 Hz).

Recording Power Meter---A meter that indicates how much audio signal is recorded on the tape.

Reject Lever---A lever that rejects or deletes a given track in a cassette player. Remote Control A means of operating a TV, VCR, compact disc, cassette player or receiver from a distance.

Ribbon Speaker---A high-frequency driver or tweeter that uses a ribbon material suspended in a magnetic field to generate audio sound.

Rumble---Low frequency vibrations that are transmitted or picked up by the audio system.

Self-Erase---A partial erasure of information on the magnetic tape.

Self-Powered Speaker---A speaker with a built-in amplifier.

Sensitivity---The sensitivity of a speaker is the measured output of the speaker in dB compared to the input.

Separation---The separation of two stereo audio channels.

Signal---A form of music or voice carried in electronic form.

Signal Processing---Converting the laser beam from digital to audio in the CD player.

Signal-to-Noise Ratio (SN)---The higher the signal-to-noise ratio, the better the sound. The ratio of the loudest signal to that of hiss or noise.

SMD---Surface mounted devices. Tiny electronic components that mount directly on the pc wiring.

Solenoid---A coil with an iron-core that switches in a cassette, CD player, or TV set. The for adjustment and Troubleshooting procedures.

Speaker Enclosure The cabinet or box in which the speakers are mounted.

Standard Play---The speed that a two-hour (T120) VHS cassette plays on a VCR.

Standing Waves A wave created of bouncing or reflected sound back to the original wave. Standing waves can cause distortion.

Subwoofer---A speaker designed to handle frequencies below 150 Hz.

Test Cassette ---Recorded signals on a test cassette used for adjustment and trouble shooting procedures.

Tone Control---A control circuit designed to increase or decrease the amplification of a specific frequency range.

Total Harmonic Distortion (THD)---The amplifier total distortion is to feed a signal in and measure the harmonic distortion at the output terminals.

Transducer---A device that converts energy into another form. The microphone converts sound into electrical energy.

Tweeter---A high-frequency driver speaker.

Vented Speaker System---A speaker cabinet with a port to let the back waves of the speaker to escape.

Voice Coil---A coil of copper wire attached to the cone of a speaker that converts electrical signal to movement of cone to create audible sound.

Watts---The measurement of power.

W/CH --- Watts per channel.

Woofer---The low frequency driver or largest speaker in the audio system.

Wow---A slow change in fluctuation or speed of tape. The fast speed variation is called flutter.

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