Click on a letter or number to jump to listings of terms that correspond. [ 5 | A | B | C | D | E | F | G | H | I | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y ] Term Definition Demo Early Reflections Those sounds that arrive at a listener's ears after one reflection from a room boundary. Echo A reflected sound that arrives after a delay sufficient for a listener to distinguish it as a discrete event in time. In rooms this is modified by the reverberation time of the space. Edge-driven Dome Tweeter A tweeter that uses a voice coil wound around a voice coil former that has the same diameter as the tweeter's radiating area. Edge-driven tweeters often provide higher power handling than balanced, or W-Dome tweeters. Edgewound Ribbon Voice Coil A loudspeaker voice coil that is made from wire flattened into a metal ribbon and then wound on edge. This maximizes the amount of wire in the magnetic gap, improving the performance of a loudspeaker motor. EDTV See: Enhanced-Definition Television. Efficiency The measure of a device's ability to convert input power to work. Expressed as a percentage. See: Sensitivity Electrolytic Capacitor A common form of capacitor consisting of a conductive film in an electrolyte. Tends to be used for larger values of capacitance. Electromagnet A magnet consisting of wire wound around a soft iron core. It becomes an active magnet when current is passed through the wire, and it ceases to be a magnet when the current stops. See: Magnet Electronic Crossover An electrical filter designed to limit the band of frequencies that is sent to the input of an amplifier connected to a loudspeaker designed to reproduce only a certain band of frequencies, i.e. a subwoofer, midrange driver or tweeter. See also Crossover Electrostatic Commonly referring to loudspeakers in which a thin conductive membrane serves as the diaphragm driven by electrostatic forces generated between it and fixed perforated electrodes in front of and behind it. Requires a polarizing voltage, and high voltages to drive it. Electrically capacitive. Usually radiating a dipole sound field. Small maximum displacements limit low frequency output and necessitate large diaphragms, and consequent directivity issues. See: Dipole, Directivity. EMC EMC (Electromagnetic Compatibility) refers to electromagnetic disturbance that occurs when different electronic devices are connected. See EMI. EMI Electromagnetic interference created when a device radiates electromagnetic waves that are received by other devices. Some kinds of electric motors, car ignitions and computers are notorious for radiating EMI. AM radio is a common indicator of EMI. Enclosure The box, or other shape of volume, that accommodates the transducers in a loudspeaker system. Normally, its shape is dictated by the acoustical needs of the mid and high frequency drivers, and the volume is determined by the design chosen to complement the performance of the woofer. There are several options for low-frequency enclosures, closed, bass reflex, passive radiator, etc. See: Transducer, Driver, Woofer, Bass Reflex, Acoustic Suspension. Enhanced-Definition Television A broadcast system in which existing equipment is used to transmit an enhanced signal. It looks no different on standard television receivers but is enhanced when viewed on those with the extra feature. EQ See: Equalizer Equal Loudness Contours Graphs displaying contours of equal perceived loudness for single frequencies or narrow band sounds. Each contour is referenced to 1 kHz, and shows the variations in physical sound level required to maintain equal perceived loudness at all audible frequencies. There have been several determinations, for different sounds, under different listening conditions. Fletcher and Munson, Robinson and Dadson, and Stevens are among the best known investigators. See Phon. Equalization The process of using an equalizer to correct for problems in an audio system. The difficulty is to know what the problem is caused by, and whether it is the kind of problem correctable with an equalizer. Measurements are usually advised. Equalizer A device consisting of adjustable filters that can change the frequency response of an audio system. Equalizers can compensate for frequency response aberrations in loudspeakers, loudspeaker/room combinations, and also for adjusting the tonal balance of recordings. See also: Graphic Equalizer, Parametric Equalizer, Tone Controls. Excursion The in and out movement of a loudspeaker diaphragm. Extended Pole Piece A form of loudspeaker motor design in which the front of the pole piece is extended to improve the uniformity of the magnetic field within which the voice coil moves. This reduces distortion at large excursions.