Labels:text | screenshot | font | black and white | document OCR: Note: terms followed by an asterisk (*) have individual articles. acoustic feedback - In LP-record playing, an undesirable sound that is caused by vibrations from the loudspeaker creating extra vibrations in the cartridge stylus. acoustic suspension - A type of loudspeaker* in which the motion of the woofer cone is stabilized by air pressure within the sealed cabinet. AM (amplitude modulation*) - A method of broadcasting in which the desired audio or video signal modulates the amplitude of a "carrier" signal. antenna* - An array of metal rods or wires used to intercept radio waves and convert them into electrical currents. bandwidth - The range of frequencies over which a device operates effectively. bass - The lowest audible frequencies, between approximately 20 and 200 cycles per second. bass reflex - A type of loudspeaker whose low-frequency response is augmented by sound waves emerging from within the cabinet via a port or freely suspended cone. Also called a "ported " or "vented " speaker. bias - In tape recording, an ultrasonic signal that is mixed with the audio signal during recording. Bias reduces noise and distortion and affects the frequency response. binaural - Stereo recordings that are made with microphones mounted in a dummy head and intended for playback through headphones. cartridge (cartridge, stereo*) - The phonograph pickup, consisting of a stylus assembly and the miniature circuits that transform stylus vibration into an electrical signal. CD (compact disc*) - A digitally encoded record, aluminized to reflect light and played with a low-power laser. A 12-cm (4.7- in) CD contains up to 74 minutes of stereo sound. CD-I (compact disc-interactive) - A "multi-media "CD combining audio, video, still pictures, and text and used in conjunction with TV. CD-V (compact disc-video) - A variant form of CD containing up to 5 minutes of video and 20 minutes of digital audio. coaxial - Refers to devices having the same center. In a coaxial speaker, the tweeter is mounted in the center of the woofer. A coaxial cable consists of a central wire surrounded by insulation and an outer wire forming a cylindrical shield against interference. crossover - An electronic filter circuit that separates low from high frequencies and channels them to the woofer and tweeter, respectively. DAT - Digital audiotape, usually packaged in a cassette. DAT employs the same digital coding and provides the same sound quality as the compact disc. DBX - An audio equipment manufacturer and developer of noise-reduction systems used in tape recording and in stereo television sound. DCC - (Digital Compact Cassette) A cassette tape format that employs perceptual coding. digital - (1) A method of representing sound waves as a series of binary numbers. (2) A tuning method for radios, in which the desired frequency is set by digital calculation. (3) A numeric display of information. direct drive - A turntable drive system in which the spindle and platter are part of the motor itself. distortion - Changes in a signal that involve the addition of spurious tones at frequencies not present in the original sound. h "harmonic " distortion the spurious tones are at integral multiples of the original frequency. In "intermodulation " distortion, discordant tones appear at the sums and differences of two original frequencies. Dolby B, C, and S - Noise-reduction circuits for consumer tape recorders. Two other circuits, Dolby A and SR, are used in recording studios. Dolby Digital - A system of five-channel surround sound for motion pictures, based on Dolby AC-3 perceptual coding. Dolby Stereo - A system of noise-reduction, equalization, and surround sound, used for motion-picture sound tracks. dropout - A momentary loss of signal in a tape recording, usually caused by wear, dust, or a tape defect. dubbing - (1) The process of copying a recording to make a duplicate. (2) h motion-picture sound, replacing a foreignlanguage soundtrack with dialogue in the language of the audience. dynamic range - The ratio between the loudest and softest sounds that can be reproduced accurately by a recording medium. equalization - Changes in amplification at low or high frequencies, done to compensate for the limitations of a recording medium and to obtain equally accurate reproduction at all frequencies. flutter - Unwanted variation in the speed of a turntable or tape recorder. Slow flutter, or "wow, " causes musical sound to waver in pitch. FM ( frequency modulation*) - A method of broadcasting or recording in which the desired audio or video signal modulates ( varies) the frequency of a "camier" signal. FMX (Extended-range FM.) - A noise-reduction system that permits hiss-free reception of FM broadcasts at large distances or with small antennas. frequency response - The principal measures of the fidelity of any sound- reproducingdevice . graphic equalizer - A tone-control device whose amplification can be varied by octave, using slider controls whose positions provide an approximate visual graph of the frequency response.
